Formulation development and optimization of herbo synthetic lipospheres based on solidified reverse micellar solutions for therapeutic management of diabetes mellitus

Abstract

The therapeutic efficacy of bioactives from Anogessius leiocarpus, a medicinal plant widely used in folkloric medicine in Nigeria in the management of diabetes mellitus (DM), can be improved using novel drug delivery systems. The objective of this study is to evaluate the antidiabetic potentials of Anogessius leiocarpus root bark extracts and lipospheres delivery system loaded with A. leiocarpus root-bark methanol extract compared with glibenclamide, a standard antidiabetic. The root bark was powdered and then extracted using methanol, 95% ethanol, and a combination of 95% ethanol and trona using a Soxhlet extractor. Preliminary antidiabetic properties of A. leiocarpus root-bark extracts were determined in alloxanized rats, and thereafter the optimized methanol extract was formulated into lipospheres containing 1, 2 and 3%w/w of the extract by high-shear homogenization using 10%w/w lipid matrix composed of 30% Phospholipon® 90H in 70% beeswax. Physicochemical properties, in vitro drug release in simulated intestinal fluid (SIF, pH=7.4) and simulated gastric fluid (SGF, pH=1.2) and anti-diabetic properties were determined. The phytochemical screening revealed the presence of saponins, alkaloids, glycosides, steroids, reducing sugars, flavonoids and tannins. Spherical particles with particle size range 135±1.58 - 195±2.24μm, which were stable over four weeks were obtained. Higher drug release in SIF (up to 100%) than SGF (<50%) and a mixed order release mechanism were obtained. The formulations caused significant (P<0.05) reduction in blood glucose level which was comparable with that obtained with glibenclamide. Lipospheres are a potentially safer and cheaper alternative therapeutics for DM given the numerous side effects associated with conventional glibenclamide.