Enhancement of Aqueous Solubility and Dissolution Profile of Atorvastatin Calcium: In vitro Evaluation of Solid Dispersion

Abstract

Purpose: The objective of the present study was to formulate solid dispersions (SD) of Atorvastatin calcium to improve the aqueous solubility and dissolution rate to facilitate faster onset of action. Atorvastatin calcium is a lipid lowering agent belonging to BCS-II having low solubility and high permeability.

Methods: In the present study, Solid Dispersions of Atorvastatin calcium was prepared by Kneading  and Solvent evaporation method with different polymers. SD’s were characterized by % practical yield, drug content, Solubility, FT-IR, DSC (differential scanning calorimetry), PXRD (Powder X- ray diffractometry), SEM (Scanning electron microscopy), in vitro dissolution studies and Stability studies. 

Results: The percent drug release of prepared solid dispersion of ATC by kneading method (KMP4 and KMG5) in 1:4 and 1:5 ratios was found 73.00+0.24 and 63.00+0.46 respectively. The percent drug release of solid dispersion of ATC by solvent evaporation method (SEP2 and SEG3) in 1:2 and 1:3 ratios was found 82.80+0.35 and 77.56+0.45 respectively. DSC studies revealed that there was no interaction between drug and carrier where as the PXRD demonstrated that there was a significant decrease in crystallinity of pure drug present in the solid dispersions, which resulted in an increased aqueous solubility and dissolution rate of Atorvastatin calcium.

Conclusion: The significant increase in aqueous solubility and dissolution rate of Atorvastatin was observed in solid dispersion as the crystallinity of the drug decreased after addition of P188 and Guar Gum.