Stability of Compounded Topical Nifedipine in Cream, Gel, and Ointment Bases.

The objective of this study was to investigate the stability of compounded nifedipine cream in gel and ointment formulations dispensed in white plastic and glass amber jars. Extemporaneously compounded nifedipine cream (Glaxal Base), gel (K-Y Jelly), and ointment (Aquaphor) in white plastic and glass amber jars were stored at 4°C, 23°C, and 40°C. We determined potency on days 0, 7, 14, 30, 60, and 90, and subsequently assigned beyond-use-dates based on United States Pharmacopeia recommendations, organoleptic properties, and pH changes. Nifedipine potency in cream and ointment stored in white plastic jars was within ±10% of initial for 90 days (excluding day 14 for cream). In glass amber jars, potency was outside the acceptable range by day 14 at 23°C but within range for 90 days at 4°C (excluding day 30). Nifedipine potency was maintained for 90 days in both jars at 23°C and 4°C (excluding day 30) and in white plastic jars at 40°C, but 60 days stored in glass amber jars. The pH of formulations was stable with changes of less than 1-unit pH. At 40°C, a significant decrease in apparent viscosity of cream was evident on day 90. There was a decrease in apparent viscosity and phase separation of the ointment at 40°C and an increase in apparent viscosity (difficult to mix) at 4°C on day 14 onwards. Significant organoleptic changes were observed by day 7 at 40°C (decrease in apparent viscosity and abnormal odor by day 90), day 30 at 4°C (thicker consistency), and day 90 at 23°C (abnormal odor). Storage in white plastic jars at 23°C is recommended for compounded topical nifedipine cream and ointment (for 90 days), and for gel (60 days).