Novel anti-ulcer phytosomal formulation of ethanol extract of pentaclethra macrophylla stem-bark

Abstract

Pentaclethra macrophylla, a medicinal plant widely used for ulcer treatment in Nigeria by herbal practitioners, is limited by poor lipid solubility, resulting in poor absorption and bioavailability. Phytosomes, a novel dosage form that are better absorbed and produce better results than conventional herbal extracts, could be employed to enhance its antiulcer activity. The objective of this study was to formulate Pentaclethra macrophylla stem-bark extract as phytosomes by forming complexes with phospholipid and compare the antiulcer activity with omeprazole, a standard anti-ulcer drug. Phytosomal formulations of ethanol extract of Pentaclethra macrophylla stem-bark and Phospholipon® 90G (P90G) (extract:P90G ratios of 1:1, 1:3, 1:5) were prepared following established method. Their physicochemical properties, in vitro drug release in simulated intestinal fluid (SIF, pH=7.4) and simulated gastric fluid (SGF, pH=1.2) and anti-ulcer properties on aspirin-induced ulcer using Wistar rats were determined and compared with omeprazole. Phytosomes with spherical smooth particles with size range 0.106-0.217 µm and good encapsulation efficiencies (range = 67.61-72.8%) were obtained. Drug release increased with time irrespective of phospholipid concentration or dissolution medium. The extract possessed antiulcer activity (23.33%) which was increased to 33.33, 43.33 and 56.67% by formulating it as phytosomal formulations containing extract:P90G ratios of 1:1, 1:3, 1:5, respectively. However, omeprazole and its formulations gave significantly (p<0.05) greater antiulcer activity when compared with both the ethanol extract and phytosomes. Pentaclethra macrophylla stem-bark possessed antiulcer activity, which was improved via phytosomal formulation. This would serve as potential safer and cheaper alternative therapeutics for ulcer given the side-effects associated with omeprazole.