Physicochemical and dissolution studies of simvastatin solid dispersions with Pluronic F127.

Simvastatin (SIM) solid dispersions with Pluronic F127 (PLU) obtained by kneading and fusion methods were characterized by differential scanning calorimetry (DSC), X-ray powder diffraction (XRPD) and Fourier Transform Infrared Spectroscopy (FTIR). DSC studies demonstrate that the SIM/PLU solid dispersions formed a simple eutectic phase diagram. FTIR spectroscopy and XRPD studies of obtained mixtures showed no interaction between the components in the solid state and confirmed the absence of terminal solid solutions. Intrinsic dissolution studies of solid dispersions in 0.5% sodium lauryl sulfate solution (SLS) indicated that the dissolution rate markedly increased in these solid dispersions systems compared with pure SIM. The increase in dissolution rate strongly depended on ratios of drug to carriers and selection of the method of preparations of mixtures. The solid dispersions prepared in the weight ratios of 60.0/40.0% and 69.9/30.1% w/w of SIM/PLU by the kneading method showed the highest improvement in wettability and dissolution rate of SIM. Approximately 100% of the drug was dissolved from these mixtures in comparison to 3.84% of pure simvastatin within 120 min.