Atorvastatin–cyclodextrin systems: Physiochemical and biopharmaceutical evaluation

The aim of the present investigation was to enhance the solubility and dissolution of atorvastatin, a poorly water soluble drug with cyclodextrins (CDs) for improving its bioavailability. The binary system of atorvastatin with CDs was prepared by different techniques. The in-vitro and in-vivo characterization was carried out to determine the effectiveness of solid complex on bioavailability. The phase solubility diagram with both cyclodextrins was classified as AN – type (nonlinear) isotherm, which indicates the non ideality effects or of self association by the ligand. The dissolution rate was remarkably increased in binary system, compared with the physical mixture and pure drug. The presence of new solid phase and the stronger interaction with the CDs are an evident from the solid state analysis. Furthermore, the binary systems with HPβCD using freeze drying method at drug: carrier ratio of 1:5 showed the superior effect on solubility and dissolution. The developed tablet formulation showed better dissolution rate than that of marketed product. Moreover, the optimal formulation performed better than pure drug in both pharmacokinetic and pharmcodynamic aspect. This could be primarily recognized to the enhancement of drug dissolution associated with stronger interaction of HPβCD.

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