Studies on enhancement of solubility and dissolution properties of rosiglitazone hydrochloride by solid dispersion technique

Abstract

Rosiglitazone HCl, a member of thiazolidinedione class of antidiabetic agent, improves glycemic control by improving insulin sensitivity. The maximum solubility of rosiglitazone was found at pH 1.2 and solubility decreases up to pH 4.0. At a pH 6.0 and higher pH, solubility reduces drastically. Suitable solid dispersion systems of rosiglitazone with maltodextrin and poloxamer were prepared by solvent evaporation and kneading methods at 1:1 and 1:3 drug: carrier. Drug content, saturation solubility, FTIR, XRD, DSC and In-vitro dissolution were studied. The drug content was uniform, solubility of the drug increased linearly as a function of the carrier concentration and method. The FTIR studies suggest possible interaction at molecular level further justified by XRD and DSC studies. The dissolution study suggests, the increase in drug release was dependent on type of method of preparation. The DP60 and DE60 values were significantly higher (P<0.05) in solid dispersion systems prepared by kneading method when compared to pure rosiglitazone, physical mixture and solvent evaporation method. The dissolution follows first order model and obeyed Hixson- Crowell’s cube root law.