Use of anhydrous calcium phosphate and selected binders in the tablet formulation of a deliquescent crude plant extract: Vernonia galamensis (Asteraceae)

In this study, the effect of anhydrous calcium phosphate, 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 of the leaves of Vernonia galamensis (Asteraceae). Materials used include; anhydrous calcium phosphate (BDH chemicals Ltd. Poole, England), maize starch and gelatin (May and Baker, Germany). Granule and tablet analyses were carried out according to standard procedures in the BP 2007. 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. The mechanical strengths and drug release properties of the designed tablets were assessed using the crushing strengthfriability, disintegration time ratio (CSFR:DT) and dissolution rate. An increase in binder concentration led to an increase in crushing strength, decrease in friability and increase in disintegration time of the tablets. Anhydrous calcium phosphate used as diluent along with polyvinylpyrrolidone as binder produced the best quality tablets in terms of the CSFR: DT ratio and dissolution rate as compared to the diluent used with maize starch and gelatin as binders.