Microencapsulation of minocycline hydrochloride using polylactide and polylactide-co-glycolide

Abstract

The present study was designed to develop sustained release microcapsules of minocycline hydrochloride by water-in-oil-in-water solvent evaporation technique. Effects of polymer type (poly (L-lactide), poly (DL-lactide), poly (DL-lactide-co-glycolide) 75:25, and poly (DL-lactide-co-glycolide) 50:50), stabiliser concentration (sodium carboxymethylcellulose), and core to wall ratio on yield, encapsulation efficiency, and release characteristic were investigated. Increasing sodium carboxymethylcellulose decreased encapsulation efficiency. The core to wall ratio of 1:5 gave the highest yield and drug entrapment. Microcapsules prepared by using poly (DL-lactide-co-glycolide) 75:25 gave high percent entrapment similar to poly (L-lactide). The release profile of poly (DL-lactide-co-glycolide) 75:25 was higher than poly (L-lactide), poly (DL-lactide), and poly (DL-lactide-co-glycolide) 50:50, respectively. The release kinetics followed first order. Microcapsules prepared by using poly (L-lactide), poly (DL-lactide), and poly (DL-lactide-co-glycolide) 50:50 had residual organic solvent conforming to the United States Pharmacopeia limits. Poly (L-lactide) and poly (DL-lactide) were suitable to prepare sustained release microcapsules of minocycline hydrochloride because they displayed extended release profile more than 48 hours.