Solidified Reverse Micellar Solution-Based Lipid Microparticles of Miconazole Nitrate: Formulation Design, Biopharmaceutical Characterization, and Dissolution Studies

Abstract

The present work was aimed at formulating solidified reverse micellar microparticles (SRMMs) using templated lipids (Softisan 154, stearic acid, and Phospholipon ®90H) for improved biopharmaceutical performance, dissolution of miconazole nitrate. SRMMs containing miconazole nitrate (MN) (1, 2, and 3% w/w) were formulated using Softisan® 154 (SOFT) and stearic acid (ST) and their combinations, containing Phospholipon® 90H (P90H) by melt homogenization employing Polysorbate 80 as the surfactant. The microparticles were freeze-dried, characterized, and optimized batches evaluated for in vitro dissolution in methanolic HCl and antifungal activity. The average SRMM yield was 70%. Entrapment efficiency and loading capacity determination showed that the lipid matrix composed of Softisan® 154 and Phospholipon® 90H (7:3) possessed greater entrapment than the other matrices with the 5% SOFT + P90H matrix containing 3% MN entrapping 98.48% of the drug. Preliminary anticandidal evaluation of the formulations showed significant activity of all the formulations containing drug. DSC analysis of the lipid excipients and matrices showed slight modifications in the physical nature of the excipients. Further analysis using X-ray diffraction showed retention of drug form in the formulations though with slight alterations in d-spacings of the X-ray diffractograms. In vitro dissolution studies of the optimized batches revealed a significant (p < 0.05) increase in dissolution rates of optimized SLM batches compared with pure MN. Kinetic modelling of the in vitro dissolution data revealed that most of the matrix systems evaluated best fitted the Korsenmeyer-Peppas model. SRMMs improved the in vitro dissolution and antifungal activity of MN.