Drug-release Assessment of Compounded Topical Nifedipine and Diltiazem in Commonly Used Bases for Wound Healing

The objective of this study was to determine release profiles of extemporaneously compounded nifedipine and diltiazem in commonly used bases in pharmacy practice. Release of nifedipine 0.2%, 2%, and 10% (w/w) from Glaxal Base, K-Y Jelly, and Aquaphor Healing Ointment, and of diltiazem 2% (w/w) from GlaxalBase, hydroxyethyl cellulose-based gel, and white petrolatum was quantified using the Franz-cell diffusion system. The cumulative release was determined at 0.5 hour, 1 hour, 1.5 hours, 2 hours, 3 hours, 4 hours, and 6 hours. Two-way ANOVA with Tukey's posthoc test was used for statistical analyses, with a P-value of <0.05 considered significant. At a 0.2% concentration, cumulative nifedipine release was highest from Glaxal Base. At 2% and 10% concentrations, nifedipine release was highest from K-Y Jelly, although this was only significantly different from Glaxal Base at 6 hours and 1.5 hours, 4 hours, 6 hours (P<0.05), respectively. Diltiazem release from Glaxal Base and white petrolatum was significantly lower than the gel (P<0.05). No significant difference in diltiazem release from Glaxal Base at 0.5 hour was observed versus white petrolatum (P>0.05). Nifedipine and diltiazem release both followed Higuchi's mathematical model with the highest coefficient of determination (R2) for all formulations. Of the bases studies, Glaxal Base is the recommended base for compounding topical nifedipine (0.2%). For higher concentrations of nifedipine (2% and10%), both Glaxal Base and K-Y Jelly are suitable options for base selection. A hydroxyethylcellulose-based gel is recommended for topical diltiazem (2%).