Animal Health Solutions

11 Q4 2021 | Animal Health Solutions Other USP updates New beyond-use date concepts and requirements introduced A beyond-use date (BUD) is the expiration date for compounds. A BUD is assigned based on different, more conservative criteria than expiration dates of manufactured drug products. A BUD must be assigned to every compounded drug to ensure the finished preparation maintains its accepted potency, purity, quality, and characteristics until that date. The compounder consults and applies drug-specific stability literature when available and considers its degradation mechanism, dosage, potential for microbial growth, packaging/container, storage conditions, and intended duration of therapy. Regardless of the active pharmaceutical ingredient within the compound, it is generally accepted that water-based mediums are at higher risk for growing bacteria as compared with oil-based ones; thus, oil-based compounds can have a longer shelf-life (eg, 90 days vs 14 days). 8 Compounding industry representatives have expressed concerns that the proposed USP updates for BUD classification and assignment are not sufficiently clear and may restrict therapeutic use of compounded drug products. 9 This will likely affect many compounds for animal use. A complete overview of BUD proposed changes can be found at usp.org/sites/default/files/usp/ document/our-work/compounding/usp-bud-factsheet. pdf. 8 The proposed USP changes would alter the microbial contamination risk levels of certain bases (ie, water- based, oil-based, or mixtures) and introduce the concept of water activity to classify compounded products as compared with the previous nomenclature, which categorized compounds as "nonaqueous" or "aqueous." The change results in shortened BUDs due to microbial risk recategorization. One change that would likely affect veterinary practice is the significantly shortened shelf-life of fixed oil suspensions. Veterinary compounders commonly make liquid oral compounds with an oil base because animals tolerate it well (much better than humans) and because a 6-month supply can be safely made, although it should be noted that BUDs vary by state. Using an oil base is labor- and cost-saving for the pharmacist and pet owner. However, according to the new USP changes, liquid suspensions would have a much more limited shelf-life. The change is substantial and confusing; a nonaqueous formulation used to be good for 180 days, but now the same formulation could only be used for 90 days. 8 BUDs for topical and dermal compounds are also changing. Currently, a water-containing topical/dermal compound has a 30-day BUD, but under the proposed changes, the same compound is only useable for 14 or 35 days, depending on the presence of a preservative. 8 The USP committee assures compounders and practitioners that the proposed changes are based on experience in performing stability studies and previous comments raised by some clinicians. 8 The compounding industry can be confusing and frustrating to navigate, but due to its indispensable role in veterinary medicine, it remains critical for veterinarians to stay abreast of its rules and regulations.

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