Abstract:
The study was aimed at evaluating the antidiabetic potentials of Anogeissius leiocarpus DC Guill and Perr root bark methanol, ethanol and ethanol plus trona extract; and preparing, characterizing and evaluating lipospheres as drug delivery system loaded with A.leiocarpus root bark methanol extract.
400 mg/kg of methanol,ethanol and ethanol plus trona extracts of the A.leiocarpus root bark extracts were used in preliminary evaluation of antidiabetic effect of this plant root bark extracts in alloxan induced diabetic albino rats. Phytochemical analysis and spectral characteristics of the methanol root bark extract was done using UV Vis spectrophotometer. The methanol extract was further used to formulate lipospheres using lipid matrix composition chosen based on previous experience with 30% w/w Solid Lipid Nanoparticles, SLN, prepared and evaluated in our laboratory. Hot homogenization technique was used in the preparation of the lipospheres containing 1, 2, 3%w/w of A.leiocarpus methanol extract., and 1.6%w/w of glibenclamide lipospheres.
Some properties of the drug loaded lipospheres evaluated included particle size, morphology, pH and drug content. The in vitro drug release from the lipospheres was evaluated using Simulated Intestinal Fluid without pancreatin (SIF, pH=7.4) and Simulated Gastric Fluid without pepsin (SGF, pH=1.2). The blood glucose reduction after oral administration of the formulations to alloxan induced diabetic rats was determined using glucometer.
Results showed spherical particles with sizes in the range of 135± 1.58μm to 195 ± 2.24 μm. The pH analyses showed stable preparations without significant changes in pH which remained within the acidic region. There was significant (P<0.05) reduction in the blood glucose level from the initial level up to 60% reduction. The formulated lipospheres containing A. leiocarpus 1% -3% w/w when compared with glibenclamide 1.6% showed no significant (p > 0.05) differences in reduction of the initial blood glucose level of the diabetic rats, after 8 hrs of oral administration. Drug release profile was high in SIF, up to 100% and low in SGF (< 50%). Evaluation of the mechanisms of drug release revealed mixed order of release, Higuchi and Ritger Peppas in SIF and predominantly Higuchi in SGF. This suggests that the mechanisms of drug release from the lipospheres were dissolution and diffusion dependent.
This study has shown that Anogeissius leiocarpus DC Guill and Perr root bark has antidiabetic properties. Formulation of its methanol extracts as lipospheres increased its oral bioavailability and its efficacy in the reduction of blood glucose levels of the alloxan induced diabetic rats. This also shows that plant extracts with poor water solubility can be formulated into lipospheres as drug delivery carrier to facilitate their therapeutic effects.
