Dissolution Enhancement of Atorvastatin Calcium by Cocrystallization

To enhance the dissolution rate of the poorly soluble drug atorvastatin calcium (ATC) bycocrystallization with selected coformers. Enhancement of the dissolution rate and solubility of thedrug, which is classified as Class II of the Biopharmaceutical Classification System (BCS), is expectedto enhance the bioavailability.

Two methods were used for preparing the cocrystals, solvent drop grinding (SDG) andsolvent evaporation (SE) method using 1:1, 1:3, and 1:10 drug-coformer molar ratios. Glucosaminehydrochloride (GluN) and nicotinamide (NIC) were investigated as coformers. The cocrystals,their physical mixtures, and the raw ATC were characterized by fourier transform infrared (FTIRspectroscopy), differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), massspectroscopy (MS), scanning electron microscopy (SEM), solubility, and dissolution rate studies.

SDG and SE were effective in improving the dissolution rate of ATC with both coformers.Drug: coformer ratio 1:3 was optimum. The solubility values for ATC, GluN-, and NIC-cocrystals were26, to 35 and 50 μg/mL, respectively. The dissolution rate of ATC from cocrystals was > 90% after 5minutes, compared to 41% untreated ATC.

Cocrystallization significantly improved the solubility and dissolution, in comparison tothe untreated ATC.