Variability of compounded topical 0.2% nifedipine formulations

Abstract

AbstractBackgroundThis aim of the study was to conduct a quality analysis of compounded formulations of topical nifedipine 0.2% obtained from retail compounding pharmacies.MethodsNifedipine preparations were purchased in triplicate (refills two weeks apart) from nine commercial compounding pharmacies and assessed for: (1) label and information in compliance with regulations; (2) content homogeneity, determined by content assessment of samples from the top, middle and bottom of each preparation and microscopic assessment of crystals; (3) prescription uniformity (i.e. determining the content of each of the refills compared with the first prescription dispensed); and (4) microbiological contamination.ResultsOnly two providers labelled the product as a compounded product, and only one compounder included a lot or batch number and storage instructions. Of the 81 samples (from nine pharmacies) analysed, only 22 complied with the US Pharmacopoeia standard for potency being 90–115% of label claim; the lowest potency detected was 48.5% and the highest was 157.5%.ConclusionPatients prescribed topical 0.2% nifedipine received compounded formulations that were incorrectly or inappropriately labelled and with considerable variability in potency and content uniformity.