Sustained-Release Glibenclamide-Loaded Solid Lipid Microparticles from Micellar Solutions of Homolipids

Fat from Capra hircus (goat fat) has been widely used for drug delivery. In this work, 1:1, 1:2, and 2:1 of goat fat and Softisan® 142 were melted together, cooled at room temperature, and the resultant matrix further modified with Phospholipon 90G (4:1) to obtain solidified reverse micellar solutions (SRMS). SRMS were used to prepare solid lipid microparticles (SLMs) loaded with or without glibenclamide, a poorly water soluble antidiabetic drug by hot melt homogenization. Particle size, morphology, thermal behavior, drug encapsulation efficiency, in vitro release study, and in vivo fate in diabetogenic rats were investigated. We report here an improved drug holding capacity (70.35%) of the lipid matrix of SRMS 2:1 due to imperfection of the lipid mixtures showing lower transition temperatures (117.0 °C) and enthalpies (−12.5 mW/mg). In vitro drug diffusion showed 66.98% drug release from SLM 2:1 exhibiting non-Fickian diffusion model (anomalous behavior) and almost zero-order kinetic. SLM 2:1 also gradually released 56.98% of glibenclamide under 16 h and maintained a steady state till 24 h; generally lowering blood glucose from 600 to 120 mg/dL unlike SLM 1:2 which showed burst glibenclamide release of 22.66% within 30 min with consequent rise in blood sugar. The 2:1 micellar solution (SRMS) of homolipids could deliver glibenclamide in a sustained form better than the conventional tablet form.