Nifedipine in compounded oral and topical preparations

The purpose of this study was to evaluate nifedipine oral and topical compounding formulas and procedures. Topical preparations were compounded in Plastibase 50 W, using combinations of two drug sources and four types of light exposure. Oral preparations were compounded using combinations of two drug sources, two types of light exposure, and four suspending vehicles. Drug sources consisted of the contents of commercial nifedipine soft-gelatin capsules and nifedipine powder USP. Light exposures were ambient, red-shaded, gold-shaded fluorescent light. Topical formulations were assessed for potency, uniformity, and usability characteristics such as acceptable look and feel of the preparation. Oral formulations were assessed for potency, uniformity, and usability characteristics, such as acceptable look and taste of the preparation. Preparations which were compounded, in entirety, under gold-shaded fluorescent light with nifedipine powder USP as the drug source resulted in a potency of 90% to 110% of intended value. Preparations that were exposed to ambient or red-shaded fluorescent light at any time in the compounding procedure resulted in sub potent preparations. Nifedipine is sensitive to certain wavelengths of light resulting in rapid degradation. When exposed to fluorescent room light, significant degradation may occur in a time frame less than what may be required to compound a preparation, necessitating the need for compounding to take place under a spectrum of light that will not degrade the drug. Gold fluorescent lighting appears to prevent nifedipine degradation during compounding procedures. Concerning the drug source, the use of commercial nifedipine soft-gelatin capsules was problematic, while nifedipine powder USP is a suitable choice for the active pharmaceutical ingredient.