- Extemporaneous compounding is the on demand preparation of a drug product according to a physician's prescriptions, to meet the unique needs of an individual patient
- Compounding is regulated by individual state boards of pharmacy. Some states have their own regulations by many accept standards of the United States Pharmacopeia - National Formulary (USP-NF)
Regulations
- The pharmacist has the responsibility and authority to manage the compounding area
- Ingredients of USP-NF purity or better are to be used when compounding formulation
- A compounding record and formulation record are required for each compounded formulation
Stability and Beyond use dates
- Beyond use dates are required on compounded formulation
Compounding Considerations
- There are four area of considerations when compounding
- whether or not to compound
- before compounding
- during compounding
- after compounding
Equipment
- Class A torsion balances can weigh as little as 120mg of material with a 5% error
- When weighing an amount of ingredient that is less than 120mg, an aliquot or analytical balance can be used
Using a Balance
- Class A torsion balances and electronic balances need to be leveled before weighing ingredients
- Weighing papers or weighing boats should always be placed on the balance pans before weighing ingredient
Volumetric Equipment
- Liquid drugs, solvents, or additives are measured in volumetric glassware or plasticware such as graduated cylinders, syringes, and pipets
- Erlenmeyer flasks, beakers, and prescription bottles, regardless of markings, are not volumetric glassware
Measuring Liquids
- Always use the smallest device that will accommodate the desired volume of liquid
- When reading a volume of liquid against a graduation mark, hold the graduated cylinder so the meniscus is at eye level and read the mark at the bottom of the meniscus
Mixing Solids and Semisolids
- Trituration is the fine grinding of a powder. Levigation is the trituration of a powder drug with a solvent in which the drug is insoluble. Both techniques reduce the drug's particle size
- Geometric dilution must be used when mixing powders of unequal quantity
Compounding Select Dosage Forms
- Aqueous solutions are clear liquids (but not necessarily colorless) made most commonly with purified but which may also contain ethanol, glycerin, or propylene glycol
- Non-aqueous solutions include elixirs, tinctures, spirits, liniments, and oleaginous solutions
- Suspensions are a two phase system consisting of a finely divided solid dispersed in a liquid
- The flavor experience is a complex combination of taste, smell, texture, appearance, and temperature
- An emulsion is unstable system consisting of at least two immiscible (unmixable) liquids, one that is dispersed as small droplets throughout the other, and a stabilizing agent
- There are two major methods of compounding ointments:
- incorporating a drug into an ointment base
- forming the base as a part of the compounding process
- There are three classes of suppository bases defined by their composition and physical properties: oleaginous bases, water soluble or miscible bases, and hydrophilic bases
- When preparing capsules, the smallest capsule capable of containing the final formulation is used since patients often have difficulty swallowing large capsules
- Tablets are compounded in either molded, compressed, or rapid dissolve form
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