Use of avicel® ph-103 and selected binders in the tablet formulation of the deliquescent crude leaves extract of Vernonia galamensis (Asteraceae)

Abstract

A decoction of the leaves of Vernonia galamensis (Asteraceae) has been used in folk medicine for the treatment of diabetes mellitus. But because folkloric medicines have no standard dose or acceptable method of formulation, attempts have been made by some scientists to formulate crude plant extracts into tablets. The crude leaves extract of Vernonia galamensis is highly hygroscopic and deliquescent and is stored over silica gel crystals in a desiccator. In this study, the effect of a grade of microcrystalline cellulose; avicel PH-103 (FMC Corporation, USA), an efflorescent pharmaceutical powder of reduced moisture content, ideal for moisture-sensitive materials; and the comparative binding effects of maize starch, polyvinylpyrrolidone and gelatin were investigated in the tablet formulation of the deliquescent crude extract. Preparations of the binders at varying concentrations of 2.5, 5.0 and 7.5% w/v were used to produce the granules by wet granulation method and compressed into tablets at 26.25KN. Granule properties such as angle of repose, moisture content, bulk and tapped densities, Carr’s index, and tablet properties such as tablet thickness, friability, disintegration times, and dissolution rates using standard methods were investigated. An increase in binder concentration led to an increase in crushing strength, decrease in friability and increase in disintegration time of the tablets. Formulations using gelatin as binder produced the best quality tablets in terms of the CS/FR ratio, CSFR/DT ratio and dissolution rate. Gelatin can therefore be a useful binding agent in the formulation of the deliquescent crude leaves extract of V. galamensis when the efflorescent fumed silica is used as diluent.