THE APhA COMPLETE REVIEW FOR PHARMACY, 7th Ed

5. Sterile Products - Laura A. Thoma, PharmD

5-1. Parenteral Products

Introduction

Parenteral products are products that are administered by injection and that, therefore, bypass the gastrointestinal tract. Parenteral products must be sterile and free of pyrogens and particulate matter. Drugs that are destroyed, are inactivated in the gastrointestinal tract, or are poorly absorbed can be given by a parenteral route. Parenteral routes of administration may also be used when the patient is uncooperative, unconscious, or unable to swallow. This route is also used when rapid drug absorption is essential, such as in emergency situations.

Parenteral Routes of Administration

Intravenous route

An intravenous (IV) medication is administered directly into the vein. The IV route gives a rapid effect with a predictable response. It is used for irritating medications because the medication is rapidly diluted. This route does not have as much volume restriction as other parenteral routes.

bolus is an injection of solution into the vein over a short period of time. A bolus is used to administer a relatively small volume of solution and is often written as "IV push" (IVP).

An infusion refers to the introduction of larger volumes of solution given over a longer period of time. A continuous infusion is used to administer a large volume of solution at a constant rate. Intermittent infusions are used to administer a relatively small volume of solution over a specified amount of time at specific intervals.

Intramuscular route

An intramuscular (IM) medication is injected deep into a large muscle mass, such as the upper arm, thigh, or buttocks. The medication is absorbed from the muscle tissue, acting more quickly than when given by the oral route, but not as quickly as when given by the IV route. Up to 2 mL may be administered intramuscularly as a solution or suspension given in the upper arm, and 5 mL may be given in the gluteal medial muscle of each buttock. A sustained-release-type action can be achieved with certain drugs that have low solubility because they are released from muscle tissue at a slow rate. IM injections are often painful, and reversing adverse effects from medications given by this route is very difficult. Antibiotics are often given by this route.

Subcutaneous route

Subcutaneous (SC) injections of solution or suspension are given beneath the surface of the skin. Medications administered by this route are not absorbed as well as and have a slower onset of action than medications given by the IV or IM route. The volume of solution or suspension that can be injected subcutaneously is 2 mL or less. Drugs often given by this route include epinephrine, heparin, insulin, and vaccines.

Intradermal route

An intradermal injection is injected into the top layer of the skin. The injection is not as deep as an SC injection. Medications used for diagnostic purposes, such as a tuberculin test or an allergy test, are often administered by this route. The volume of solution that can be administered intradermally is limited to 0.1 mL. The onset of action and the rate of absorption of medication from this route are slow.

Intra-arterial route

An intra-arterial injection is injected directly into an artery. It delivers a high drug concentration to the target site with little dilution by the circulation. Generally, this route is used only for radiopaque materials and some antineoplastic agents.

Other routes

• Intracardiac: An injection is made directly into the heart.

• Intra-articular: Administration by injection is made into a joint space. Corticosteroids are often administered by this route for the treatment of arthritis.

• Intrathecal: An injection is made into the lumbar intraspinal fluid sacs. Local anesthetics are frequently administered by this route during surgical procedures. Preservative-free drugs should be used for intrathecal administration.

5-2. Definitions for Compounding of Sterile Preparations

Introduction

• Admixture: Parenteral dosage forms that are combined for administration as a single entity.

• Antearea: An International Organization for Standardization (ISO) Class 8 or better area where personnel hand hygiene and garbing procedures, sanitizing of supplies, and other particulate-generating activities are performed. The area contains a line of demarcation separating the clean side from the dirty side.

• Aseptic processing: The separate sterilization of a product and its components, containers, and closures, which are then brought together and assembled in an aseptic environment. The primary objective of aseptic processing is to create a sterile preparation.

• Aseptic technique: Performance of a procedure or procedures under controlled conditions in a manner that will minimize the chance of contamination. Contaminants can be introduced from the environment, equipment and supplies, or personnel (see the section on ISO classification).

• Buffer area: The area where the primary engineering control is located.

• Compounding aseptic containment isolator (CACI): An isolator that protects workers from exposure to undesirable levels of airborne drugs while providing an aseptic environment during the compounding of sterile preparations.

• Compounding aseptic isolator (CAI): An isolator that maintains an aseptic compounding environment within the isolator throughout the compounding and material transfer process during the compounding of sterile preparations.

• Critical site: Any opening or surface that can provide a pathway between the sterile product and the environment.

• Hypertonic: A solution that contains a higher concentration of dissolved substances than the red blood cell, thereby causing the red blood cell to shrink.

• Hypotonic: A solution that contains a lower concentration of dissolved substances than the red blood cell, thereby causing the red blood cell to swell and possibly burst.

• Isotonic: A solution that has an osmotic pressure close to that of bodily fluids, thus minimizing patient discomfort and damage to red blood cells. Dextrose 5% in water and sodium chloride 0.9% solutions are approximately isotonic.

• Primary engineering control (PEC): A device or room that provides an ISO Class 5 environment for the exposure of critical sites when producing compounded sterile preparations (CSPs). These devices could include a laminar airflow workbench, a biological safety cabinet, CAIs, and CACIs.

• Sterilizing filter: A filter that, when challenged with the microorganism Brevundimonas diminuta at a minimum concentration of 107 organisms per cm2 of filter surface, will produce a sterile effluent. A sterilizing filter has a nominal pore size rating of 0.20 or 0.22 micron.

• Tonicity: Osmotic pressure exerted by a solution from the solutes or dissolved solids present.

• Validation: Establishment of documented evidence providing a high degree of assurance that a specific process will consistently produce a product meeting predetermined specifications and quality attributes.

ISO Classification

The ISO Classification of Particulate Matter in Room Air is the standard for clean rooms and associated environments. Limits are expressed in particles 0.5 micron and larger per cubic meter. In contrast, the limits from Federal Standard 209E are expressed in particles 0.5 micron and larger per cubic foot (1 cubic meter = 35.31 cubic feet).

ISO class 5 area

The air in an ISO class 5 area has a count of no more than 3,520 particles 0.5 micron or larger per cubic meter of air. This area is equivalent to a class 100 area under Federal Standard 209E, where the air has a count of no more than 100 particles 0.5 micron or larger per cubic foot of air. This class is the quality of air provided by the PEC and required for sterile product preparation.

ISO class 7 area

The air in an ISO class 7 area has a count of no more than 352,000 particles 0.5 micron or larger per cubic meter. This area is equivalent to a class 10,000 area under Federal Standard 209E, where the air has a count of no more than 10,000 particles 0.5 micron or larger per cubic foot of air. This class is the quality of air usually required in the buffer area.

ISO class 8 area

The air in an ISO class 8 area has a count of no more than 3,520,000 particles 0.5 micron or larger per cubic meter. This area is equivalent to a class 100,000 area under Federal Standard 209E, where the air has a count of no more than 100,000 particles 0.5 micron or larger per cubic foot of air. The antearea should have ISO class 8 air or better.

5-3. Sterile Product Preparation Area

Introduction

The following are examples of PECs that provide the ISO class 5 area for compounding of CSPs.

Horizontal Laminar Flow Workbench

The horizontal laminar flow workbench (HLFW) works by drawing air in through a prefilter. The prefiltered air is pressurized in the plenum for consistent distribution of air to the high-efficiency particulate air (HEPA) filter (

Figure 5-1).

The prefilter protects the HEPA filter from prematurely clogging. Prefilters should be checked regularly and changed as needed. A record of these checks and changes of the prefilter must be kept.

[Figure 5-1. Horizontal Laminar Flow Workbench]

The plenum of the hood is the space between the prefilter and the HEPA filter. Air is pressurized here and distributed over the HEPA filter.

Laminar flow is the air in a confined space moving with uniform velocity along parallel lines. The term unidirectional flow has taken the place of laminar flow in more recent publications. Unidirectional flow is airflow moving in a single direction in a robust and uniform manner and at sufficient speed to sweep particles away from the critical processing area. Inside the HLFW is an ISO class 5 area (class 100 area).

Vertical Laminar Flow Workbench

The vertical laminar flow workbench (VLFW) works like a HLFW in that the air is drawn in through the prefilter and is pressurized in the plenum for distribution over the HEPA filter. However, the air is blown down from the top of the workstation onto the work surface, not across it (

Figure 5-2).

Working in vertical laminar flow requires different techniques than does working in horizontal laminar flow. In vertical laminar flow, an object or the hands of the operator must not be above an object in the hood. In horizontal laminar flow, an object or the hands of the operator must not be in back of another object. The hands of the operator must never come between the HEPA filter and the object.

A biological safety cabinet, CAI, and CACI also use vertical unidirectional airflow to provide an ISO class 5 environment and are other examples of PECs.

[Figure 5-2. Vertical Laminar Flow Workbench]

The HEPA Filter

The HEPA filter consists of a bank of filter media separated by corrugated pleats of aluminum. These pleats act as baffles to direct the air into laminar sheets. The HEPA filter is 99.97% efficient at removing particles 0.3 micron and larger.

Certification of the HEPA filter

The velocity of air from the HEPA filter is checked with a velometer or hot wire anemometer. ISO 14644 recommends that the average air velocity should be > 0.2 m/second.

Integrity of the HEPA filter: The dioctyl phthalate (DOP) test

The integrity of the HEPA filter is checked by introducing a high concentration of aerosolized Emery 3004 (a synthetic hydrocarbon) upstream of the filter on a continuous basis, while monitoring the penetration on the downstream side of the HEPA filter.

The aerosol has an average particle size of 0.3 micron. An aerosol photometer is used to check for leaks by passing the wand slowly over the filter and the gasket. None of the surfaces shall yield greater than 0.01% of the upstream smoke concentration. Any value greater than 0.01% indicates that a serious leak is present and must be sealed. All repaired areas must be retested for compliance. At one time, DOP was used to generate the aerosol. However, because DOP is a carcinogen, Emery 3004 is now used. An electronic particle counter cannot be used to certify the integrity of the HEPA filter. The particle counter is used to determine room classification.

Buffer Area (Controlled Area)

The PEC is the cleanest area and provides an ISO class 5 (class 100) area. It must be located in a controlled environment, away from excess traffic, doors, air vents, or anything that could produce air currents greater than the velocity of the airflow from the HEPA filter. Air currents greater than the velocity of the airflow from the HEPA filter may introduce contaminants into the hood. It is very easy to overcome air flowing at 90 feet per minute.

The buffer area should be enclosed from other pharmacy operations. Floors, walls, ceiling, shelving, counters, and cabinets of the controlled area must be of nonshedding, smooth, and nonporous material to allow for easy cleaning and disinfecting. All surfaces shall be resistant to sanitizing agents. Cracks, crevices, and seams shall be avoided, as should ledges or other places that could collect dust. The floor of the buffer area shall be smooth and seamless with coved edges up the wall.

The walls of the buffer area can be sealed panels caulked with silicone or, if drywall is used, painted with epoxy paint, which is nonshedding. The corners of the ceiling and the walls shall be sealed to avoid cracks. A solid ceiling may be painted with epoxy paint, or nonshedding washable ceiling tiles that are caulked into place may be used.

Light fixtures shall be mounted flush with the ceiling and sealed. Anything that penetrates the ceiling or walls shall be sealed.

Air entering the room shall be fresh, HEPA filtered, and air conditioned. The room must be maintained in positive pressure (0.02-0.05 inches of water column) in relation to the adjoining rooms or corridors. If the buffer area is used for compounding of cytotoxic drugs, 0.01 inches of water column negative pressure is required. At least 30 air changes per hour shall occur, with the PECs allowed to provide up to 15 of the 30 required air changes per hour.

People entering the buffer area shall be properly scrubbed and gowned. Access to the buffer area shall be restricted to qualified personnel only.

Controlling the traffic in the buffer area is a critical factor in keeping the area clean. Only items required for compounding shall be brought into the buffer area. These items must be cleaned and sanitized before being taken into the buffer area. Items may be stored in the buffer area for a limited time. However, the number of items stored in the buffer area shall be kept to a minimum. All equipment used in the buffer area should remain in the room except during calibration or repair.

Because they can harbor many organisms, refrigerators and freezers should be located out of the buffer area. Computers and printers should be located outside of the buffer area because they generate many particles. However, if they are required to be in the buffer area, monitor the environment and evaluate their effect on the environment. Cardboard boxes shall not be stored in the buffer area. The items shall be removed from the boxes on the dirty side of the antearea and sanitized and transferred to the clean side of the antearea or to the buffer area for storage. Vials stored in laminated cardboard may be stored in the buffer area. Sinks or floor drains shall not be in the buffer area because potable water contains many organisms and endotoxins.

Preparation of Operators

An operator must be trained and evaluated to be capable of properly scrubbing and garbing before entering the buffer area. This requirement is critical to the maintenance of asepsis. The greatest source of contamination in a clean room is the people in the area. A seated or standing person without movement releases an average of 100,000 particles greater than 0.3 micron in diameter per minute. A person standing with full body movement releases an average of 2,000,000 particles per minute greater than 0.3 micron in diameter, and if moving at a slow walk, he or she releases an average of 5,000,000 particles. The garb is designed to help contain the particles that are being shed.

Before entering the antearea, an operator must remove all cosmetics and all hand, wrist, and other visible jewelry or piercings. Artificial nails or extenders are prohibited while working in the sterile compounding environment, and natural nails must be kept neat and trimmed. Garb is donned in an order proceeding from that considered dirtiest to that considered cleanest. Shoe covers, head and facial hair covers, and facemask or eye shields are donned before performing hand hygiene. Hands and forearms are then washed for 30 seconds with soap and water in the antearea, and hands and forearms are dried using a lint-free disposable towel or an electric hand dryer. While still in the antearea, an operator must don a nonshedding gown that zips or buttons up to the neck, falls below the knees, and has sleeves that fit snugly around the wrists. After entering the buffer area, an operator must use a waterless alcohol-based surgical hand scrub with persistent activity to again cleanse the hands before putting on sterile gloves. Sterile contact agar plates must be used to sample the gloved finger tips of compounding personnel after garbing to assess garbing competency. For successful completion of this competency, no colony-forming units can be found on any of the agar plate samples. Three consecutive, successful garbing and gloving exercises must be completed before sterile compounding is allowed. Routine application of sterile 70% isopropyl alcohol (IPA) must occur throughout the compounding process and whenever nonsterile surfaces are touched. After this initial evaluation, the entire process is repeated at least once a year for low- and medium-risk compounding and semiannually for high-risk compounding during any media-fill test procedure. The colony-forming unit action level for gloved hands will be based on the total number of colony-forming units on both gloves, not per hand.

Validation of the Operator

media fill or media transfer is when a growth promotion media is used instead of the drug product, and all the normal compounding manipulations are done. It is critical that the process mimic the actual compounding process as closely as possible and represent worst-case conditions. Usually, the medium used is soybean-casein digest, which is also known as trypticase soy broth. This medium will support the growth of organisms that are likely to be transmitted to CSPs from the compounding personnel and environment. A media fill is used to check the quality of the compounding personnel's aseptic technique. It is also used to verify that the compounding process and the compounding environment is capable of producing sterile preparations.

Initially, before an operator can compound low- or medium-risk sterile injectable products, he or she must successfully complete one media fill using sterile fluid culture media such as soybean-casein digest medium. Media fill units must be incubated at 20-25°C for a minimum of 14 days or at 20-25°C for a minimum of 7 days and then at 30-35°C for a minimum of 7 days. A successful media fill is indicated by no growth in any of the media fill units. The media fill shall closely simulate the most challenging or stressful conditions encountered during the compounding of low- and medium-risk preparation. The compounding personnel shall perform a revalidation at a minimum of once a year by successfully completing one media fill. The media fills shall be designed to mimic the most challenging techniques the operator will use during a normal day. Validation for high-risk compounding focuses on ensuring that both the process and the compounding personnel are capable of producing a sterile preparation with all its purported quality attributes. Revalidation must be done on at least a semiannual basis. An example of a high-risk operation is the compounding of a sterile preparation from nonsterile drug powder. To mimic this operation, the compounder must use commercially available soybean-casein digest medium made up to a 3% concentration and perform normal processing steps, including filter sterilization. All media fills must occur in an ISO class 5 environment and must be completed without interruption.

5-4. Working in the Laminar Flow Workbench

Items not in a protective overwrap shall be wiped with a lint-free wipe soaked with sterile 70% IPA before being placed in the hood. Containers and packages should be inspected for cracks, tears, or particles as they are decontaminated and placed in the hood. Items in a protective overwrap, such as bags, should be taken from the overwrap at the edge of the hood (within the first 6 inches of the hood) and placed in the hood with the injection port facing the HEPA filter. The overwrap should not be placed in the hood, because doing so would introduce particles and organisms into the hood.

When working in the HLFW, an operator shall arrange supplies to the left or right of the direct compounding area (DCA). The critical site must be in uninterrupted unidirectional airflow at all times. The compounder must be careful not to place an object or hand between the HEPA filter and the critical site because doing so would interrupt the airflow to the critical site. and potentially cause particles to be washed from the hand or object onto the critical site.

All work performed in the HLFW must be done at least 6 inches inside the hood. The unidirectional airflow is blowing toward the operator, who acts as a barrier to the airflow, causing it to pass around the body and create backflow. This turbulence can cause room air to be carried into the front of the hood.

Items placed in the HFLW disturb the unidirectional airflow. The unidirectional airflow is disturbed downstream of the item for approximately three times the diameter of the object. If the item is placed next to the sidewall of the hood, the unidirectional airflow is disturbed approximately six times the diameter of the object. Air downstream from the nonsterile objects is no longer bathed in unidirectional airflow and may become contaminated with particles. For these reasons, it is very important that a direct path exists between the HEPA filter and the area where the manipulations will occur.

With the VLFW, supplies in the hood should be placed so that the operator may work without placing a hand or object above the critical site. An operator can place many more items in the VLFW and still work without compromising the unidirectional airflow. One must remember that within 1 inch of the work surface the air is turbulent. The unidirectional air, which is coming down from the HEPA filter, strikes the work surface and changes direction to move horizontally across the work surface. Therefore, all work in the VLFW should be done at least 1 inch above the work surface. During the compounding of sterile preparations, all movements into and out of the hood must be minimized to decrease the risk of carrying contaminants into the DCA. This can be achieved by introducing all items needed for the aseptic manipulation into the work area at one time and by waiting until the procedure is completed before removing used syringes, vials, and other supplies from the PEC.

5-5. Syringes, Needles, Ampuls, and Vials

Syringes

The basic parts of the syringe are the barrel, plunger, collar, rubber tip of the plunger, and tip of the syringe. Syringes are sterile and free of pyrogens. They are packaged either in paper or in a rigid plastic container. Syringe packages must be inspected to ensure that the wrap is intact and the syringe is still sterile. Syringes have either a Luer-Lok tip, in which the needle is screwed tightly onto the threaded tip, or a slip tip, in which the needle is held on by friction (

Figure 5-3). Syringes are supplied with and without needles attached and are available in a variety of sizes. Care must be taken not to let the syringe tip touch the surface of the hood.

Calibration marks are on the barrel of the syringe. These marks are accurate to one-half the interval marked on the syringe. The critical sites on the syringe are the tip of the syringe and the ribs of the plunger. The ribs of the plunger go back inside the syringe on injection of the fluid from the syringe and could potentially contaminate the syringe.

[Figure 5-3. Types of Syringes]

Needles

The basic parts of a needle include the hub, needle shaft, bevel, bevel heel, and tip of the needle (

Figure 5-4).

Needles are sterile and are wrapped either in plastic with a twist-off top or in paper. This wrap must be inspected for integrity before the needle is used. The gauge of the needle refers to its outer diameter. The larger the number, the smaller the bore of the needle. The smallest is 27 gauge, and the largest is 13 gauge. The length of the needle is measured in inches, and some common lengths are 1.0-1.5 inches.

The critical sites on the needle are the hub of the needle, the entire needle shaft, and the tip of the needle.

[Figure 5-4. Needle]

Ampuls

Ampuls are single-dose containers. Once ampuls are broken, they are an open-system container; air can pass freely in and out of the ampul. Any solution taken from an ampul must be filtered with a 5-micron filter needle or filter straw, because glass particles fall into the ampul when it is broken. Before breaking the ampul, one shall wipe the neck of the ampul with a sterile 70% IPA prep pad.

Vials

A vial is a molded glass or plastic container with a rubber closure secured in place with an aluminum seal. It may contain sterile solutions, dry-filled powders, or lyophilized drugs, or it may be an empty evacuated container. Vials may be single-dose or multiple-dose containers.

A single-dose container usually contains no preservative system to prevent the growth of microorganisms if they are accidentally introduced into the container. A single-dose vial punctured in an environment worse than ISO class 5 air must be used within 1 hour. A single-dose vial continuously exposed to ISO class 5 air may be used up to 6 hours after initial needle puncture. When the vial is first used, it should be labeled with the date, time, and initials of the person using the vial so the length of time that the vial has been in the hood can be determined.

A multidose vial contains preservatives, and these vials can be entered more than once. The pharmaceutical manufacturer has done studies to prove that the preservative system will remain effective and the closure will reseal after penetration by the needle. Therefore, the beyond-use date for opened or entered multidose containers is 28 days, unless otherwise specified by the manufacturer.

5-6. Biological Safety Cabinets

Introduction

A class II biological safety cabinet (BSC) should be used to prepare cytotoxic and other hazardous drugs. Four different types of class II BSCs exist. Types A1 and A2 exhaust 30% of HEPA-filtered air either into the room or to the outside through a canopy connection. Type A1 mixes the supply air in a common plenum and may have ducts and plenum under positive pressure. Type A2 has all contaminated ducts and plenum under negative pressure or surrounded by negative pressure. Type B1 exhausts 70% of total air through a dedicated exhaust duct and must be hard ducted. Type B2 exhausts 100% of total air to the outside without any recirculation and must be hard ducted also. With types B1 and B2, all the ducts and the plenum are under negative pressure and are surrounded by negative pressure.

Preparation of Hazardous Drugs

When working with hazardous drugs, personnel must wear appropriate protective equipment, including gowns, face masks, eye protection, hair and shoe covers, and double sterile chemotherapy-type gloves. Personnel must handle all hazardous drugs with caution at all times, using appropriate chemotherapy gloves, not only during preparation, but also during receiving, distribution, stocking, inventorying, and disposal.

It is imperative that positive pressure not be allowed to build up in the vial. Proper training on the use of a chemotherapy-venting device, which uses a 0.2 micron hydrophobic filter or the negative pressure technique to prevent the build up of positive pressure within the vial, must be done before preparing hazardous drugs and on an annual basis. When a closed system transfer device (one that allows no venting or exposure of hazardous substance to the environment) is used, it shall be used within the ISO class 5 environment of a BSC or CACI.

When compounding, syringes and IV sets with Luer-Lok fittings must be used if possible. Use a large enough syringe so that the plunger does not separate from the barrel of the syringe when filled with solution. Syringes should be filled with no more than 75% of their total volume. When possible, attach IV sets and prime them before adding the hazardous drug. Wipe the outside of the bag or bottle to remove any inadvertent contamination. The use of nonshedding plastic-backed absorbent pads is also conducive to keeping the BSC as clean as possible.

The PEC shall be located in an ISO class 7 area physically separated from other preparation areas and maintained under negative pressure of not less than 0.01 inch water column to the surrounding area.

5-7. Overview of the Standard of Practice Related to Sterile Preparations: The United States Pharmacopeia (USP) 32/National Formulary (NF) 27

Introduction

Chapter 797, Pharmaceutical Compounding—Sterile Preparations in USP 32/NF 27, became official June 2008. Chapter 797 has three microbial risk levels of compounded sterile preparations. The risk levels are determined on the basis of the potential for the introduction of microbial, chemical, or physical contamination into the product. The chapter covers topics such as validation of sterilization and of the aseptic process, environmental control and sampling, end-product testing, bacterial endotoxins, training, and a quality assurance program.

Low-Risk Compounding

Compounding is classified as low risk when all of the following conditions prevail:

• Commercially available sterile products, components, and devices are used in compounding within air quality of ISO class 5 or better.

• Compounding involves few aseptic manipulations, using not more than three commercially manufactured sterile products and not more than two entries into any one sterile container.

• Closed-system transfers are used. Withdrawal from an open ampul is classified as a closed system.

• In the absence of passing a sterility test, the storage periods for the compounded sterile preparations cannot exceed the following time periods before administration:

• Storage for not more than 48 hours at controlled room temperature

• Storage for not more than 14 days at a cold temperature of 2-8°C

• Storage for not more than 45 days in a solid frozen state between -25°C and -10°C.

Medium-Risk Compounding

Medium-risk CSPs are those compounded under low-risk conditions when one or more of the following conditions exist:

• Compounding involves pooling of additives for the administration to either multiple patients or to one patient on multiple occasions.

• Compounding involves complex manipulations other than a single volume transfer.

• The compounding process requires a long time period to complete dissolution or homogeneous mixing.

• In the absence of passing a sterility test, the storage periods for the CSPs cannot exceed the following time periods before administration:

• Exposure for not more than 30 hours at controlled room temperature

• Storage for not more than 9 days at a cold temperature

• Storage for not more than 45 days in a solid frozen state between -25°C and -10°C.

High-Risk Compounding

High-risk compounds are compounded under any of the following conditions and are either contaminated or at high risk to become contaminated with infectious microorganisms:

• A sterile preparation is compounded from nonsterile ingredients.

• Sterile ingredients or components are exposed to air quality inferior to ISO class 5 for more than 1 hour, including storage in environments inferior to ISO class 5 of opened or partially used packages of manufactured sterile products with no antimicrobial preservative system.

• Nonsterile water containing preparations are exposed for more than 6 hours before being sterilized.

• No examination of labeling and documentation from suppliers or direct determination that the chemical purity and content strength of ingredients meet their original or compendia specification occurs.

• Compounding personnel are improperly garbed and gloved.

• In the absence of passing a sterility test, the storage periods for the CSPs cannot exceed the following time periods before administration:

• Storage for not more than 24 hours at controlled room temperature

• Storage for not more than 3 days at a cold temperature

• Storage for not more than 45 days in a solid frozen state between -25°C and -10°C.

5-8. Sterilization Methods

Filtration

Filtration works by a combination of sieving, adsorption, and entrapment. Care must be taken to choose the correct filter to sterilize the preparation. Membrane filters generally are compatible with most pharmaceutical solutions, but interactions do occur—often because of sorption or leaching. Sorption is the binding of drug or other formulation components to the filter, which can occur with peptide or protein formulations. There are filters that have little or no affinity for peptides or proteins. Leaching is the extracting of components of the filter into the solution. Surfactants are often added to the filter to make it hydrophilic, and they may leach into the product. Large-molecular-weight peptides may be affected by filtration. Their passage through a filter with a small pore size may cause shear stress and alter the three dimensional structure of the peptide. Solvents in the parenteral formulation may also affect filters. All filter manufacturers have compatibility data on their membrane type and can be a great source of information when choosing a membrane.

Filter choice

Choose the appropriate size and configuration of filtration device to accommodate the volume being filtered and permit complete filtration without clogging of the membrane. A 25 mm syringe disk filter should filter no more than 100 mL of solution. If the solution being filtered has a heavy particulate load, a 5 micron filter should be used before the 0.2 micron filter to decrease the particulate load to the 0.2 micron filter. The filter membrane and housing must be physically and chemically compatible with the product to be filtered and capable of withstanding the temperature, pressures, and hydrostatic stress imposed on the system.

A pharmacy may rely on the certificate of quality provided by the vendor. Certification shall include microbial retention testing with Brevundimonas diminuta at a minimum concentration of 107 organisms per cm2, as well as testing for membrane and housing integrity, nonpyrogenicity, and extractables.

Hydrophobic and hydrophilic filters

Hydrophilic membranes wet spontaneously with water. They are used for filtration of aqueous solutions and aqueous solutions containing water-miscible solvents. Hydrophobic filters do not wet spontaneously with water. They are used for filtering gases and solvents.

Filter integrity

A sterilizing filter assembly should be tested for integrity after filtration has occurred. The bubble point is a simple, nondestructive check of the integrity of the filtration assembly, including the filter membrane. The basis for the test is that liquid is held in the capillary structure of the membrane by surface tension. The minimum pressure required to force the liquid out of the capillary space is a measure of the largest pores in the membrane.

A bubble point test is performed by wetting the filter with water, increasing the pressure of air upstream of the filter, and watching for air bubbles downstream to indicate passage of air through the filter capillaries. The typical water bubble point pressure of a sterilizing filter with a pore size rating of 0.2 micron is > 50 pounds per square inch gauge (psig). As pore size decreases, the bubble point increases. Remember that the bubble point given on the certificate of quality from the filter manufacturer is usually the water bubble point. Many drug formulations have a lower surface tension than water and will have a lower bubble point. Bubble points are also often given for 70% IPA and water. Use the alcohol test for a hydrophobic filter.

After the solution is filtered and before the integrity of the filter membrane is checked, the filter should be flushed with water to wash as much of the product off the membrane as possible. The integrity test may then be performed.

Heat Sterilization

Moist-heat sterilization (autoclave)

Moist-heat sterilization is one of the most widely used methods of sterilization. Saturation of steam at high pressure is the foundation for the effectiveness of moist-heat sterilization. When steam makes contact with a cooler object, it condenses and loses latent heat to the object. The amount of energy released is ~524 kcal/g at 121°C. Most sterilization cycles are at 121°C at 15 psig for a minimum of 15 minutes. Moist-heat sterilization is faster and does not require as high a temperature as dry-heat sterilization. Biological indicators of Bacillus stearothermophilus and temperature-sensing devices shall be used to verify the effectiveness of the steam sterilization cycle.

Dry-heat sterilization

Dry-heat sterilization is usually done as a batch process in an oven designed for sterilization. It provides heated filtered air that is evenly distributed throughout the chamber by a blower. The oven is equipped with a system to control the temperature and exposure period. Dry-heat sterilization requires higher temperatures and longer exposure times than does moist-heat sterilization. Typical sterilization cycles are 120-180 minutes at 160°C or 90-120 minutes at 170°C. Biological indicators of Bacillus subtilis and temperature-sensing devices shall be used to verify the effectiveness of the dry-heat sterilization cycle.

Depyrogenation by dry heat

Dry heat can also be used for depyrogenation of glass and stainless steel equipment and of vials. The pyrogens are destroyed when the equipment is kept at 250°C for 30 minutes. The effectiveness of the dry-heat depyrogenation cycle shall be verified by using endotoxin challenge vials to determine whether the cycle is adequate to achieve a 3-log reduction in endotoxins.

Beyond-Use Date

Each compounded sterile preparation must have a label that specifies the correct names and amount of ingredients, the total volume, the storage requirements, route of administration, and beyond-use date (BUD). The BUD is the date after which a compounded preparation is not to be used and is determined from the date the preparation is compounded. In the absence of passing the sterility test, the CSPs must comply with the microbial BUD. If the lot of CSP has met the requirements of the sterility test, then the BUD may be based on chemical and physical stability. When assigning a BUD, compounding personnel should consult and apply drug-specific and general stability documentation and literature where available. They should consider the nature of the drug, its degradation mechanism, the container in which it is packaged, the expected storage conditions, and the intended duration of therapy.

5-9. Stability

Introduction

Stability refers to physical, chemical, and microbial stability.

Instability usually refers to chemical reactions that are incessant and irreversible and result in distinctly different chemical entities. These new chemical entities can be therapeutically inactive and possibly exhibit greater toxicity.

Incompatibility usually refers to physicochemical phenomena such as concentration-dependent precipitation and acid-base reactions that occur when one drug is mixed with others to produce a product unsuitable for administration to the patient. An incompatibility could cause the patient not to receive the full therapeutic effect, or it could cause toxic decomposition products to form. A precipitated incompatibility may irritate the vein or cause occlusion of vessels.

There are three categories of incompatibilities: therapeutic incompatibility, physical incompatibility, and chemical incompatibility.

Therapeutic Incompatibility

Therapeutic incompatibility occurs when two or more drugs administered at the same time result in undesirable antagonistic or synergistic pharmacologic action.

Physical Incompatibility

Physical incompatibility is the combination of two or more drugs in solution, resulting in a change in the appearance of the solution, a change in color, the formation of turbidity or a precipitate, or the evolution of a gas. Physical incompatibilities are related to solubility changes or container interactions rather than to molecular change to the drug entity itself.

Six major areas of concern about physical incompatibility

Compatibility or incompatibility of two or more drugs mixed in the same syringe

For example, preoperative medications—a combination of a narcotic, an analgesic, an antiemetic, and an anticholinergic—are mixed in the same syringe to save the patient from multiple IM injections.

Compatibility of two or more drugs given through the same IV administration line

This concern is common in intensive care units, where patients are often on a number of IV medications and could also be fluid restricted. For example, dopamine HCl 800 mg in 500 mL D5W (5% dextrose in water) is prescribed. The nurse wants to push 2 amps of sodium bicarbonate through the IV line. The pH of dopamine is 3.0-4.5, and that of NaHCO3 is approximately 8.0. If this push is done, a color change occurs because of decomposition of the product. The pH of the bicarbonate is too high for dopamine stability.

Compatibility of two or more drugs placed in the same bottle or bag of IV fluid

KCl, the most common additive, is a neutral salt composed of monovalent ions that are not likely to produce compatibility problems. Therefore, if a drug is compatible in a neutral salt, it is probably compatible in KCl.

Parenteral nutrition solutions can be especially difficult. The number of components, the long duration of contact time, and exposure to ambient temperature and light enhance the potential for an adverse compatibility interaction to occur. The interaction of Ca and PO4 to form CaPO4, which appears as fine white particles that create a milky solution, is a problem.

Some ways to decrease the risk of injury follow:

• Calculate the solubility of the added calcium from the volume at the time when calcium is added. Flush the line in between the addition of any potentially incompatible components.

• Add the calcium before the lipid emulsion. Therefore, if a precipitate forms, the lipid will not obscure its presence.

• Periodically agitate the admixture, and check for precipitates. Train patients and caregivers to visually inspect for signs of precipitation and to stop the infusion if precipitation is noted.

The following factors enhance formation of precipitate of calcium and phosphate:

• High concentrations of calcium and phosphate

• Increases in solution pH

• Decreases in amino acid concentrations

• Increases in temperature

• Addition of calcium before phosphate

• Lengthy time delay or slow infusion rates

• Use of the chloride salt of calcium.

Do not exceed 15 mEq of Ca with up to 15 mL PO4 per 1000 mL of solution.

Compatibility of the additive with the composition of the IV container itself

Nitroglycerin readily migrates into many plastics, especially polyvinylchloride (PVC). Insulin adsorbs to IV tubing, filters, and both glass and plastic containers.

Compatibility of the additive with the additional equipment used to prepare or administer the IV admixture

Cisplatin interacts with aluminum by forming a black precipitate when coming in contact with it.

Stability of the drug after admixture

Ampicillin sodium is stable for 72 hours when refrigerated and 24 hours at room temperature in normal saline. However, if it is added to D5W, it is stable for only 4 hours when refrigerated and 2 hours at room temperature.

Other potential sources of physical incompatibilities

Concentration

A drug will remain in aqueous solution as long as its concentration is less than its saturation solubility.

Cosolvent system

Drugs that are poorly water soluble are often formulated using water-miscible cosolvents. Examples of water-miscible cosolvents include ethanol, propylene glycol, and polyethylene glycol. Dilution of drugs that are in a cosolvent system often causes precipitation of the drug. A good example is diazepam injection. Dilution of the drug results in precipitation in some concentrations, but sufficient dilution to a point below diazepam's saturation solubility results in a physically stable admixture.

pH

The greatest single factor in causing an incompatibility is a change in acid-base environment. Solubility of drugs that are weak acids or bases is a direct function of solution pH. The drug's dissociation constant and pH control the portion of drug in its ionized form and the solubility of the un-ionized form. A drug that is a weak acid may be formulated at a pH sufficient to yield the desired solubility. Sodium salts of barbiturates, phenytoin, and methotrexate are formulated at high pH values to achieve adequate solubility.

Sodium salts of weak acids precipitate as free acids when added to IV fluids having an acidic pH. If the pH of these drugs is lowered, the drug's solubility at the final pH may be exceeded, resulting in possible precipitation. Drugs that are salts of weak bases may precipitate in an alkaline solution.

Ionic interactions

Large organic anions and cations may also form precipitates, such as the precipitation that occurs when heparin (anionic) and aminoglycoside antibiotics (cationic) are mixed. These heparin salts of the cationic drug are relatively insoluble in water.

Sorption phenomena

The intact drug is lost from the solution by adsorption to the surface or absorption into the matrix of container material, administration set, or filter.

Adsorption to the surface can result from interactions of functional groups within the drug's molecule to binding sites on the surfaces.

Absorption of lipid-soluble drugs into the matrix of plastic containers and administration sets, especially those made from PVC, does occur. The substantial amount of phthalate plasticizer used to make the PVC bag pliable and flexible allows the lipid-soluble drugs to diffuse from the solution into the plasticizer in the plastic matrix. Plastics such as polyethylene and polypropylene, which contain little or no phthalate plasticizer, do not readily absorb lipid-soluble drugs into the polymer core. Leaching of the phthalate plasticizer into the solution may also occur, especially if surface-active agents or a large amount of organic cosolvent is present in the formulation.

Chemical Incompatibility

Chemical incompatibilities are interactions resulting in molecular changes or rearrangements to different chemical entities. Most chemical interactions are not observable by the unaided eye.

Chemical degradation pathways

Hydrolysis is a common mode of chemical decomposition. Water attacks labile bonds in dissolved drug molecules. Functional groups labile to hydrolysis are carboxylic acid and phosphate esters, amides, lactams, and imines.

Oxidation is an electron loss that causes a positive increase in valence. Many drugs are in the reduced form, and oxygen creates stability problems. Steroids, epinephrine, and tricyclic compounds are sensitive to oxygen. For control of the stability problem, oxygen can be excluded, pH can be adjusted, and chelating agents or antioxidants can be added.

Reduction is when an electron is gained, causing a decrease in valence and the addition of halogen or hydrogen to the double bond. β-lactam antibiotics can produce reducing aldehydes on hydrolysis.

Photolysis is the catalysis by light of degradation reactions such as oxidation or hydrolysis. Examples of drugs that are light sensitive are amphotericin B, furosemide, and sodium nitroprusside. The reaction rate depends on the intensity and wavelength of light. Sodium nitroprusside in D5W has a faint brownish cast, but exposure to light causes deterioration, which is evident by a change in color to blue caused by the reduction of the ferric to ferrous ion.

Extreme pH can be a catalysis of drug degradation. Drug reaction rates are generally less at intermediate pH values than at high or low ranges. A buffer system is often used to ensure the maintenance of the proper pH.

Effects of temperature may be evident. Usually, but not always, an elevation in temperature may increase reaction rates.

An increase in drug concentration will usually increase the degradation rate exponentially. However, this rule does not always apply. Some drugs appear to have a lower rate of decomposition at a high concentration, such as the reduced hydrolysis of nafcillin in the presence of aminophylline. Greater buffer concentration at higher nafcillin concentrations protects the drug from aminophylline's high pH and slows the hydrolysis.

Expiration dates and removal of the IV bag overwrap are important. The overwrap protects against evaporation of the solution, desiccation of the container, drug oxidation, and photochemical inactivation of the drug. Substantial moisture loss may occur, increasing drug concentration. With ready-to-use dopamine or dobutamine injections, removal of the overwrap can allow oxygen to enter the container, thereby reducing drug stability. After removal of the overwrap, the expiration date should be changed at once.

5-10. Sterile Products Compounded from Nonsterile Drugs

Introduction

When a sterile preparation is compounded from a nonsterile component, several concerns arise: how to sterilize the drug, how to sterilize the container and closure, and how to ensure that the drug and components are sterile. Every sterilization process must be verified, whether it is terminal sterilization of the CSP in the final container or aseptic processing of the CSP. Sterility testing must be done on all high-risk compounded sterile preparations if they are prepared in groups of more than 25 single-dose packages or in multidose vials for administration to multiple patients. Such testing must also be done if prior to sterilization the preparations are exposed longer than 12 hours to temperatures of 2-8°C or longer than 6 hours to temperatures warmer than 8°C. If the high-risk CSPs are dispensed before the results of the sterility test are known, a method must be in place requiring daily observation of the test specimens and immediate recall of the CSP if there is evidence of microbial growth in the test sample.

Sterility Testing

There are two methods of sterility testing: direct inoculation and membrane filtration. The USP states that, when possible, membrane filtration should be performed and that two culture media are required: fluid thioglycollate medium (FTM) and trypticase soy broth (TSB), which is also known as soybean-casein digest medium.

Media suitability test

Before beginning the test, one must confirm that the medium being used is sterile and will support the growth of microorganisms.

Sterility

Confirm the sterility of each sterilized batch of medium (1) by incubating a portion of the batch at the specified incubation temperature (TSB, 20-25°C; FTM, 30-35°C) for 14 days or (2) by incubating uninoculated containers as negative controls during a sterility test procedure. When purchasing a new batch of sterile media from a vendor, one should incubate a portion for several days to ensure that it did not become contaminated during shipment.

Growth promotion test

Each lot of ready-prepared medium and each batch of dehydrated medium bearing the manufacturer's lot number must be tested for its growth-promoting qualities. Separately inoculate, in duplicate, containers of each medium with fewer than 100 viable microorganisms of each of the strains listed in the next paragraph. If visual evidence of growth appears in all inoculated media containers within 3 days of incubation in the case of bacteria and 5 days of incubation in the case of fungi, the test media is satisfactory. The test may be conducted simultaneously with testing of the media for sterility.

The organisms to be used for the growth promotion test of FTM are Staphylococcus aureus (Bacillus subtilis may be used instead), Pseudomonas aeruginosa (Micrococcus luteus may be used instead), and Clostridium sporogenes (Bacteroides vulgatus may be used instead). The test organisms for soybean-casein digest media are Bacillus subtilis, Candida albicans, and Aspergillus niger. Soybean-casein digest media are incubated at 20-25°C, and FTM are incubated at 30-35°C, both under aerobic conditions for a minimum of 14 days.

Validation test: Bacteriostasis and fungistasis test

The bacteriostasis and fungistasis test must be done on each product to determine if the product itself will inhibit the growth of microorganisms. This test needs to be done only once for each product tested. The organisms used are the same as those used for growth promotion. The test uses two sets of containers. One set is inoculated with the drug product and microorganisms, and the other set is inoculated with just the microorganisms. Both sets will be incubated at the appropriate temperature for no more than 5 days. The same amount of growth should be seen in both sets. If the drug is inhibiting the growth of the microorganisms, the conditions of the test must be modified so the drug will not inhibit growth. The modifications made will now become the method for performing the sterility test on the drug preparation.

Number of articles to test

The minimum number of articles to be tested in relation to the number of articles in the batch are as follows:

• For up to 100 articles, test 10% or 4 articles, whichever is greater.

• For more than 100 but not more than 500 articles, test 10 articles.

Interpretation of results

No growth

At days 3, 5, 7, 10, and 14, examine the media visually for growth. If no microbial growth is seen, the article complies with the test for sterility. Lack of growth of the media does not prove that all units in the lot are sterile.

Observed growth

When microbial growth is observed and confirmed microscopically, the article does not meet the requirements of the test for sterility. If there is no doubt that the microbial growth can be ascribed to faulty aseptic techniques or materials used in conducting the testing procedure, the test is invalid and must be repeated.

An investigation must occur, and the organism must be identified down to the species. All records must be reviewed, including all employee training procedures and records, aseptic gowning practices, equipment maintenance records, component sterilization data, and environmental monitoring data.

Visual inspection

Every unit compounded in the pharmacy should be subjected to a physical inspection against a white background and a black background. Any container whose contents show evidence of contamination with visible foreign material must be rejected.

Pyrogens

A pyrogen is a substance that produces fever. An endotoxin is a type of pyrogen.

Gram-negative bacteria produce more potent endotoxins than do Gram-positive bacteria and fungi. The lipopolysaccharide (LPS) portion of the cell wall causes the pyrogenic response. The LPS can be sloughed off, and the bacteria do not have to be living for the LPS to be pyrogenic.

Some of the effects caused by pyrogens in the body are an increase in body temperature, chills, cutaneous vasoconstriction, a decrease in respiration, an increase in arterial blood pressure, nausea and malaise, and severe diarrhea.

The official endotoxin limits are 5 endotoxin units (EU)/kg per hour or 350 EU/total body per hour for drugs and biologicals. Drugs for intrathecal use have a much lower endotoxin limit of 0.2 EU/kg.

Water is the primary source of endotoxins because Pseudomonas, a Gram-negative bacterium, grows readily in water. Other sources of endotoxins or pyrogens are raw material, equipment, processing, and human contamination. It is very important to use good-quality raw materials and request a certificate of analysis with each lot of material when compounding. Endotoxins can be destroyed by dry heat. Three to five hours at 200°C will depyrogenate glass vials and beakers. The endotoxin concentration can be reduced by rinsing with sterile water for injection. When a sterile preparation is compounded from a nonsterile product, any equipment that can withstand the heat of 200°C should be depyrogenated. An article that is depyrogenated is also sterile. Endotoxins are not completely removed by filtration, and steam sterilization reduces endotoxin levels by only a small amount.

Pyrogen test (rabbit test)

The pyrogen test is designed to limit, to an acceptable level, the patient's risk of febrile reaction in the administration—by injection—of the product concerned. The test involves measuring the rise in temperature of rabbits following the IV injection of a test solution, and it is designed for products that can be tolerated by the test rabbit in a dose—not to exceed 10 mL/kg—injected intravenously within a period of no more than 10 minutes.

The rabbit test has several limitations. It is an in vivo method, it is an expensive and time-consuming test, and it is not a very sensitive test. Drugs that have pyretic side effects or that are antipyretics cannot be tested using the rabbit test. The test is not quantitative, and the pyrogenic response is dose dependent, not concentration dependent.

Bacterial endotoxin test (limulus amebocyte lysate test)

The bacterial endotoxin test (BET) provides a method for estimating the concentration of bacterial endotoxins that may be present in, or on the sample of, the article to which the test is applied using limulus amebocyte lysate (LAL) reagent. Because the blood cells of the horseshoe crab are sensitive to endotoxin and form a gel in its presence, LAL reagent is made from the lysate of amebocytes from the horseshoe crab.

There are two types of techniques for this test: the gel-clot technique, which is based on the formation of the gel, and the photometric technique, which is based on either the development of turbidity or the development of color in the test sample.

The routine gel-clot test requires 0.1 mL of test sample to be mixed with 0.1 mL of LAL reagent. This mixture is incubated for 1 hour at 37°C. A positive reaction is confirmed by formation of a firm gel that remains intact when the tube is slowly inverted 180 degrees.

The BET is 5-50 times more sensitive, more simple and rapid, and less expensive than the pyrogen test. However, the clotting enzyme is heat sensitive, pH sensitive, and chemically related to trypsin. It is dependable for detection of only pyrogens originating from Gram-negative bacteria. Also, some drugs can inhibit the reaction, and other drugs can enhance the reaction. The BET does not determine the fever-producing potential of the bacterial endotoxins.

The photometric technique requires the establishment of a standard regression curve. The endotoxin content of the test material is determined by interpolation from the curve. The test can be either an endpoint determination, in which the reading is made immediately at the end of the incubation period, or a kinetic test, in which the absorbance is measured throughout the reaction period.

All high-risk CSPs (except those for inhalation and ophthalmic use) that are prepared in groups of 25 or more individual single-dose units or in multidose vials for administration to multiple patients, or that are exposed longer than 12 hours to temperatures of 2-8°C and longer than 6 hours to temperatures warmer than 8°C before sterilization, must comply with the BET.

5-11. Key Points

• A sterilizing filter (0.2 micron) is required to filter sterilize a CSP. The integrity of the filter must be tested before the preparation may be released. The test is often referred to as the bubble point test.

• The high-efficiency particulate air filter is 99.97% efficient at filtering out particles 0.3 micron and larger. Certification of the HEPA filter involves testing the velocity of airflow from the filter and the integrity of the filter.

• The air in an ISO class 5 area has no more than 3,520 particles 0.5 micron and larger per cubic meter of air. The laminar flow workbench provides an ISO class 5 area.

• The critical site is any opening or pathway between the CSP and the environment. The larger the critical site is and the longer it is exposed to the environment, the greater the risk of contamination of the preparation.

• The bacterial endotoxin test is designed to detect the level of bacterial endotoxin from Gram-negative organisms in the CSP. All bacterial endotoxins are pyrogens, but not all pyrogens are bacterial endotoxins.

• The sterility test and the BET should be performed on all high-risk compounded sterile preparations intended for administration by injection into the vascular or central nervous system that are prepared in groups of more than 25 identical individual single-dose packages or in multidose vials for administration to multiple patients. The BET must be performed before the CSP can be dispensed.

• Any pharmacist preparing CSPs must have training in aseptic technique. One way to validate aseptic technique is by performing media fills. The growth medium most often used is trypticase soy broth, also known as soybean-casein digest medium in the USP.

• The laminar airflow in a horizontal laminar flow workbench flows toward the operator. The operator must never put his or her hands in back of an object, between the HEPA filter and the critical site. Never break first air.

• The laminar airflow in a vertical laminar flow workbench flows down onto the work surface.

• A biological safety cabinet should always be used for preparing cytotoxic drugs. All biological safety cabinets have vertical laminar airflow.

• The hot air oven is used to depyrogenate items used in compounding and to sterilize compounded preparations that cannot be sterilized by steam.

• Moist-heat sterilization is a common way to sterilize equipment used in the compounding process. Only items that can be moistened by steam can be sterilized by autoclaving.

5-12. Questions

1.

Which of the following tests does not have to be completed on a high-risk compounded sterile preparation that will be administered by intravascular injection and is prepared in a lot size of 30 single-dose vials before release to a patient?

A. Bacterial endotoxin test

B. Visual inspection

C. Sterility test

D. Verification of the sterilizing filter integrity

E. LAL test

 

2.

Which of the following is correct concerning certification of a laminar flow workbench?

A. The particles introduced into the plenum of the hood must be approximately 0.5 micron.

B. Airflow from the HEPA filter must be 120 ft/min.

C. A leak greater than 0.01% of the upstream smoke concentration through the filter is considered a serious leak.

D. A total particle counter can be used to check the integrity of the HEPA filter.

E. If a HEPA filter leaks, it cannot be patched; it must be replaced.

 

3.

The bacterial endotoxin test is used to determine

A. the amount of pyrogens.

B. the level of pyrogens from Gram-negative bacteria.

C. the fever-producing potential of bacterial endotoxins from Gram-negative bacteria.

D. the level of bacterial endotoxin from Gram-positive bacteria.

E. the amount of live bacteria present in the drug solution.

 

4.

Which of the following is correct concerning USP media transfers?

A. An operator must successfully complete one media fill before compounding any CSPs.

B. An operator who passes a written exam may compound sterile preparations until the chief pharmacist finds time to watch his or her aseptic technique.

C. An operator who has successfully completed a media fill must requalify semiannually if he or she is preparing low-risk CSPs.

D. When an operator successfully completes one media fill for high-risk compounding, he or she needs to revalidate quarterly by completing one media fill.

E. Fluid thioglycollate media are used for media transfers.

 

5.

For a transfer of product into the controlled area,

A. bottles, bags, and syringes must be removed from brown cardboard boxes before being brought into the buffer area.

B. vials stored in laminated cardboard may not be brought into the controlled area.

C. stainless steel carts may be used to transfer items into the controlled area directly from the storage area.

D. large-volume parenteral bags of IV solution must be removed from their protective overwrap before being brought into the controlled area.

E. the refrigerator should be placed next to the laminar flow hood for easy access.

 

6.

Which of the following is correct concerning a vertical laminar flow hood?

A. It is always a biological safety cabinet.

B. In vertical laminar flow, the hands of the operator must not be behind an object.

C. A vertical laminar flow hood has turbulent airflow within 1 inch of the work surface.

D. A vertical laminar flow hood has the laminar airflow blowing at the operator.

E. The operator works in a vertical flow hood and a horizontal flow hood in the same manner.

 

7.

Certain factors may increase the risk of microbial contamination of a CSP. Which of the following would not be a risk factor?

A. Very complex compounding steps

B. Lengthy exposure of a critical site during compounding

C. Use of appropriate aseptic technique

D. Batch compounding without preservatives for multiple patients

E. Preparation of a CSP from nonsterile powders

 

8.

Which of the following is correct concerning the USP risk levels of compounded sterile preparations?

A. Preparations intended for administration over 3 days would be classified as low risk.

B. A high-risk sterile preparation that has met the requirements of the sterility test can be stored for not more than 24 hours at a controlled room temperature.

C. The storage time for a medium-risk preparation under refrigeration is no longer than 9 days.

D. A CSP that will be administered to multiple patients or to a single patient multiple times is classified as a high-risk CSP.

E. After meeting the requirements of the sterility test, a sterile preparation can be stored indefinitely.

 

9.

Which of the following is correct?

A. For work done in a horizontal laminar flow workbench, arrange items in the hood so that your hand is never between the HEPA filter and an object.

B. For work done in a horizontal laminar flow workbench, vials that are not being used should be stacked up along the side of the hood to increase workspace in the hood.

C. Before each shift, 70% isopropyl alcohol is used to sterilize the laminar flow workbench.

D. An object placed in the horizontal laminar flow workbench disturbs the airflow downstream of the object equal to two times the diameter of the object.

E. Syringes and IV bags are placed in the hood in their protective overwrap.

 

10.

Which of the following is correct concerning the necessity that operators in the buffer area be properly gowned?

A. Operators don gowns because they shed particles, and the nonshedding gowns keep them sterile.

B. Sterile gloves are used to avoid contamination of the CSP in case the operator accidentally touches a critical site during compounding of the preparation.

C. Frequent sanitization with sterile 70% isopropyl alcohol is essential to keep the operators' hands sterile during the compounding process.

D. Nonshedding garb and sterile gloves help to contain the particles shed from the operators.

E. Operators must don gowns before working at the laminar flow workbench but not before entering the buffer area.

 

11.

Which of the following is correct concerning placement of items and work performed in the laminar flow workstation?

A. Items should be placed in a horizontal flow hood to the right or left of the work area.

B. Items in a vertical laminar flow hood should be placed so that an operator's hand never goes over the top of a critical site while the operator is working in the hood.

C. An object placed in a horizontal laminar flow hood disturbs the airflow downstream of the object equal to three times the diameter of the object.

D. When working in a horizontal laminar flow workstation, an operator must perform all work at least 6 inches inside the hood.

E. All of the above are correct.

 

12.

Which parts of the syringe are considered critical sites?

I. The ribs of the plunger

II. The collar of the syringe

III. The tip of the syringe

A. I only

B. II only

C. I and III only

D. II and III only

E. I, II, and III

 

13.

Which parts of the needle are considered critical sites?

I. The hub

II. The needle shaft

III. The bevel and bevel tip of the needle

A. I only

B. II only

C. I and III only

D. II and III only

E. I, II, and III

 

14.

Which of the following are correct concerning ampuls?

I. Ampuls are single-dose containers.

II. Ampuls must have the neck wiped with a sterile alcohol pad before being broken.

III. Ampuls can be left in the hood and used for several days once opened.

A. II only

B. I and III only

C. I and II only

D. I, II, and III

E. None of the above

 

15.

Which of the following are correct concerning the steps taken to protect an operator when working with cytotoxic agents?

I. Preparation of cytotoxic drugs must occur in a biological safety cabinet.

II. Syringes with Luer-Lok tips should be used when compounding cytotoxic CSPs.

III. It is very important that positive pressure not be allowed to build up inside the vial when one is working with cytotoxic preparations.

A. I only

B. II only

C. I and III only

D. II and III only

E. I, II, and III

 

16.

Which of the following is correct?

A. Filter integrity testing of the filter membrane is done to determine at what pressure the filter will break.

B. The manufacturer of the filter membrane determines the bubble point of the membrane; this value is always the same, no matter what solution has been filtered.

C. As the pore size of the filter membrane decreases, the pressure at which the air can be pushed from the largest pore increases.

D. The bubble point test is a destructive test.

E. It is not necessary to perform the bubble point test if a certificate of quality from the filter manufacturer is provided.

 

17.

Which of the following factors should be considered when choosing a sterilizing filter?

A. The volume of solution to be filtered

B. The compatibility of the membrane with the solution to be filtered

C. Whether the solution to be filtered is hydrophobic or hydrophilic

D. The compatibility of the filter housing with the product to be filtered

E. All of the above

 

18.

Which of the following is correct concerning the USP sterility test?

A. The validation test must be done on each CSP to determine if the article to be tested adversely affects the reliability of the test.

B. The growth promotion test does not require that the test organisms listed in the USP be used.

C. After inoculation, the media must be incubated for 14 days or fewer at the appropriate temperature.

D. No growth on the sterility test proves that the aseptically produced product is sterile.

E. Trypticase soy broth is incubated at 30-35°C, and fluid thioglycollate is incubated at 20-25°C.

 

19.

Which of the following is correct?

A. Gram-negative bacteria must be alive to cause a pyrogenic response.

B. The lipopolysaccharide portion of the cell wall of Gram-negative bacteria causes the pyrogenic response.

C. Endotoxin can be removed by a 0.2 micron filter.

D. Steam sterilization will depyrogenate an object just as well as the hot air oven.

E. An article that is depyrogenated is not necessarily sterile.

 

20.

Which of the following is correct?

A. The rabbit test and the LAL test are the same test.

B. LAL reagent will determine the fever-producing potential of the pyrogens.

C. There are two types of techniques for the BET: the gel-clot technique and the photometric technique.

D. The CSP being tested has no effect on the test.

E. All CSPs may be tested using the rabbit test.

 

21.

Which of the following is correct?

A. The rabbit test is the most sensitive because it can detect pyrogens from all sources.

B. The rabbit test is an in vitro test.

C. Some drugs may inhibit the formation of a gel in the BET.

D. No drug will enhance the formation of the gel in the BET.

E. The pyrogen test is a quantitative test.

 

22.

The plenum in a laminar flow workbench is the area

A. where the air is prefiltered.

B. where air is pressurized for distribution over the HEPA filter.

C. where compounding takes place.

D. that serves no purpose.

E. directly above the HEPA filter in a horizontal laminar flow hood.

 

23.

Calcium and phosphate can interact to form a precipitate in parenteral nutrition solutions. Of the following situations that could enhance precipitate formation, which one would not do so?

A. High concentration of calcium and phosphate

B. Increase in solution pH

C. Decrease in temperature

D. Use of the chloride salt of calcium

E. A slow infusion rate

 

24.

Of the following potential sources of physical or chemical incompatibilities, which is not a source?

A. Dilution of a drug in a cosolvent system into an aqueous system

B. Addition of a drug solution with a high pH into a solution with a low pH

C. Adsorption of a lipid-soluble drug into the matrix of a polypropylene container

D. A photosensitive drug such as sodium nitroprusside in 5% dextrose in water exposed to light

E. Leaching of phthalate plasticizer into the solution from a polyvinyl chloride container

 

5-13. Answers

1.

C. The bacterial endotoxin test (LAL test), visual inspection test, and bubble point test should all be completed before the CSP is dispensed. Because the sterility test takes 14 days, the preparation may be dispensed before the results are known. However, a system to recall the CSP must be in place if it does not meet the test's requirement.

 

2.

C. Any leak greater than 0.01% of upstream smoke concentration is a serious leak. The smoke particles are 0.3 microns. The airflow from the HEPA filter should be 90 ft/min, plus or minus 20%. A total particle counter is used to classify the environment, not to certify the integrity of the HEPA filter. The HEPA filter can be patched.

 

3.

B. The BET determines the level of bacterial endotoxin from Gram-negative bacteria only. The BET cannot determine fever-producing potential of the endotoxins. The Gram-negative bacteria do not have to be alive for the endotoxin to produce an effect.

 

4.

A. The operator must successfully complete one media fill before compounding a sterile preparation. Once validated for low- or medium-risk compounding, the operator must revalidate annually. For high-risk compounding, the operator must revalidate semiannually. Passing only a written exam does not allow the operator to compound a CSP. Trypticase soy broth is the medium most often used in media fills.

 

5.

A. Cardboard must be kept out of the buffer area. Vials stored in laminated cardboard may be stored in the buffer area. No items should be brought into the buffer area without being sanitized. Large-volume parenteral bags should be removed from their overwrap just before being used. The refrigerator should not be in the buffer room because it is a source of contamination.

 

6.

C. There are several types of vertical laminar flow hoods, of which the biological safety cabinet is one. The operator must never work over the top of items in the hood, and all work should be done at least 1 inch above the work surface.

 

7.

C. Use of good aseptic technique is one way to ensure a good preparation.

 

8.

C. A medium-risk CSP may not be stored longer than 9 days at cold temperature. USP 797 does not address administration at all; it applies only up to the time of administration. Once a CSP has met the requirement of the sterility test, the storage periods specified under the risk levels no longer apply. However, the beyond-use date based on chemical stability always applies. A CSP that will be administered to multiple patients or to a single patient multiple times is a medium-risk CSP.

 

9.

A. In an HLFW, never put your hand behind an object, and in a VLFW, never put your hand above an object. In an HLFW, a vial disturbs the laminar airflow equal to three times the diameter of the object. If the vial is next to the side wall, the airflow is disturbed equal to six times the diameter of the object. Syringes and IV bags should be taken from their overwrap at the edge of the hood.

 

10.

D. Operators in the buffer area should wear clean, nonshedding gowns and gloves to help contain the particles that they shed. The sterile gloves are no longer sterile once they are out of the package. Proper aseptic technique must always be used.

 

11.

E. All of the statements are correct concerning placement of items and work performed in the laminar flow workstation.

 

12.

C. The ribs of the plunger and the tip of the syringe are critical sites of the syringe.

 

13.

E. The hub, the needle shaft, and the bevel and bevel tip of the needle are all critical sites.

 

14.

C. Once an ampul is opened, it must be used immediately.

 

15.

E. When working with cytotoxic agents, an operator must take the following steps for protection: (1) preparation must occur in a biological safety cabinet, (2) syringes with Luer-Lok tips must be used, and (3) positive pressure must not be allowed to build up inside the vial.

 

16.

C. The bubble point test is not a destructive test, and the value depends on the solution being filtered. When a CSP is filter sterilized, the bubble point test must be done before the preparation may be dispensed.

 

17.

E. All of the factors should be considered.

 

18.

A. The validation (bacteriostasis and fungistasis test) must be completed one time for each CSP. The growth promotion organisms listed in the USP are used for the validation test and for the growth promotion test.

 

19.

B. Endotoxin will pass through a 0.2 micron filter. Steam sterilization will not depyrogenate an article. Bacteria do not have to be alive to be pyrogenic.

 

20.

C. The pyrogen test, also known as the rabbit test, determines the fever-producing potential of the pyrogens. The BET is also known as the LAL test. The drug product can inhibit or enhance the gel formation in the BET.

 

21.

C. The pyrogen (rabbit) test is an in vivo test and is not as sensitive as the BET. It is not a quantitative test.

 

22.

B. The plenum is the area behind the HEPA filter in an HFLW that allows air to be pressurized for even distribution over the filter.

 

23.

C. An increase in temperature could enhance precipitate formation.

 

24.

C. Absorption of a lipid-soluble drug into the matrix of polyvinylchloride containers does occur. Polypropylene and polyethylene contain little or no phthalate plasticizer.

 

5-14. References

Akers MJ, Larrimore D, Guazzo D. Parenteral Quality Control: Sterility, Pyrogen, Particulate and Package Integrity Testing. 3rd ed. New York: Marcel Dekker; 2003.

American Society of Health-System Pharmacists. ASHP guidelines on quality assurance for pharmacy-prepared sterile products. Am J Hosp Pharm. 2000;57:1150-69.

Anderson RA. The status of environmental control: Practical approaches to the safe handling of anticancer products. Proceedings of a symposium in Mayaguez, Puerto Rico, November 2-5, 1983.

Buchanan C, McKinnon B, Scheckelhoff D, Schneider P. Principles of Sterile Product Preparation. Bethesda, Md.: American Society of Health-System Pharmacists; 2002:50.

General Services Administration. Federal standard 209e: Clean room and work station requirements, controlled environments. Washington, D.C.: U.S. Government Printing Office; 1992.

McKinnon B, Avis K. Membrane filtration of pharmaceutical solutions. Am J Hosp Pharm. 1993; 50:1021-36.

Trissel LA. Handbook on Injectable Drugs. 15th ed. Bethesda, Md.: American Society of Health-System Pharmacists; 2009.

United States Pharmacopeial Convention. Bacterial endotoxin test. In: United States Pharmacopeia, 32nd Revision: National Formulary. 27th ed. Rockville, Md.: United States Pharmacopeial Convention; 2009:93-96.

United States Pharmacopeial Convention. Compounded sterile preparations. In: United States Pharmacopeia, 32nd Revision: National Formulary. 27th ed. Rockville, Md.: United States Pharmacopeial Convention; 2009: 318-41.

United States Pharmacopeial Convention. Pyrogen test. In: United States Pharmacopeia, 32nd Revision: National Formulary. 27th ed. Rockville, Md.: United States Pharmacopeial Convention; 2009: 124-25.

United States Pharmacopeial Convention. Sterility tests. In: United States Pharmacopeia, 32nd Revision: National Formulary. 27th ed. Rockville, Md.: United States Pharmacopeial Convention; 2009: 80-86.