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Q: I have received several prescriptions for amphotericin B capsules to be compounded for patients with "systemic yeast infections." The prescriber specified "amphotericin B oral grade." I cannot find an "oral grade."
A: The question points to the increasing relevance of the US Pharmacopoeia/National Formulary (USP-NF) to the compounding pharmacist. The USP Convention makes available a USP-NF for pharmacists containing fewer drug substance monographs than the full USP-NF, emphasizing those most likely to be used in extemporaneous compounding. It also contains sections on "Compounding Support Information," "Safe Medication Practices," and others.
Chemicals labeled "USP," "NF," or "USP-NF" are suitable for use in humans in the United States. The route of administration is to be determined by the physician and the pharmacist, based on the indication and dosing. In the case of amphotericin B, USP29-NF24 2006 contains 5 different monographs besides a Reagent Standard: "Amphotericin B," "Amphotericin B Cream," "Amphotericin B for Injection," "Amphotericin B Lotion," and "Amphotericin B Ointment." No monograph entitled "Amphotericin B for Oral Use" or "Amphotericin B Oral Grade" is found. According to the "Amphotericin B" monograph, "Amphotericin B has a potency of not less than 750 μg of C47H73NO17 per mg, calculated on the dried basis."
The monograph "Amphotericin B for Injection" contains specific labeling (administration to hospitalized patients only), storage (protected from light and refrigerated), pH (7.2-8.0 in water), and administration conditions (protect from light).
For compounding a preparation for human administration, the USP monograph <795>, Pharmaceutical Compounding-Nonsterile Preparations, states that the USP or NF grade substance "is the preferred source of ingredients." If it is not available, the monograph gives alternatives. Your supplier should indicate that the powder is "for dermatological or oral use," but not that it is "oral grade," because the "grade" is USP, no matter into what form the product is to be incorporated.
It is important to note, also, that there is little to no absorption of amphotericin B when administered orally. This factor should be considered when administering amphotericin B to patients with systemic fungal infections.
Mr. Erickson is director of professional affairs at Gallipot Inc.
E-mail your compounding questions to firstname.lastname@example.org