IMPROVEMENT SOLUBILITY OF ATORVASTATIN CALCIUM USING SOLID DISPERSION TECHNIQUE

This study focused on an investigation of dissolution property of solid dispersion system consisting of drug, exipients, and carrier. The purpose of this study was to enhance the dissolution of Atorvastatin Calcium, a practically water-insoluble drug by preparation of solid dispersion using hydrophilic polymers and a carrier PEG 6000. Solid dispersion formulations were prepared by using The Melt Solvent and physical mixing method. Physical mixtures (PMs) of atorvastatin and hydrophilic polymer Kollicoat IR and PVK 30 were prepared at 1:0.5, 1:1 and 1:2 ratios. Melt Solvent method was used to prepare solid dispersion of atorvastatin, PVK 30 and kollicoat IR at 1:2 ratio. Solid dispersions were characterized by differential scanning calorimetry, scanning electron microscopy and dissolution tests. Characterization studies revealed that solid dispersion of Atorvastatin prepared by Melt Solvent methods showed better dissolution compare to Physical mixing and pure atorvastatin  due to the conversion of atorvastatin into a less crystalline and/or amorphous form. The order of dissolution enhancement was Kollicoat IR > PVK30 in solid dispersions as well as in physical mixtures. Improvement of dissolution was significantly greater in solid dispersions prepared by Melt solvent method than in physical mixtures. The differential scanning calorimetric studies indicated that a decreased crystallinity of the solid dispersions obtained revealed that a portion of Atorvastatin was in an amorphous state. This was because of Kollicoat IR and PVK 30 affected the crystallinity of the drug could be considered as an important factor in enhancement the dissolution rate. It is known that amorphous drug represents the most ideal case for fast dissolution.