The Effect of Betacyclodextrin on the Solubility and Dissolution of Spironolactone Using Physical Mixing and Co-Evaporation Methods

Abstract

Spironolactone is a steroidal drug acting as a specific aldosterone antagonist used as potassium sparing diuretic. It shows variable absorption and bioavailability due to its poor solubility. The objective of this study was to investigate the effect of betacyclodextrin (BCD) on the solubility and dissolution of spironolactone using physical mixing and coevaporation methods. The physical mixtures of different w/w drug/carrier ratios (1:1, 1:2 and 1:3) were prepared by simple mixing. Also co-evaporate systems containing (1:1, 1:2 and 1:3) w/w drug/carrier ratios were prepared. The physicochemical characterization of the systems using differential scanning calorimetry (DSC) and powder X-ray diffraction was carried out to detect the interaction between the drug and the carrier, moreover, quantitative solubility and in-vitro dissolution studies of spironolactone alone and in physical mixtures or co-evaporates were studied in simulated gastric fluid (SGF) of pH 1.2 and in simulated intestinal fluid (SIF) of pH 7.5.