Abstract

ENHANCEMENT OF SOLUBILITY AND DISSOLUTION RATE OF ATORVASTATIN CALCIUM BY CO-SOLVENT EVAPORATION

A.Geethalakshmi*, V.Divya, K.Mahalingan, Neha Rao, Krishna Hari Pandey

Department of Pharmaceutics, The Oxford College of Pharmacy, Hongasandra, Bangalore-560068.

ABSTRACT

Hyperlipidemia is a condition of elevation of lipids in the bloodstream. Atorvastatin is a drug used for lowering blood cholesterol. Atorvastatin is practically insoluble in water. Therefore, the aim of present study was to enhance the solubility and dissolution rate of Atorvastatin calcium (ATC) by cosolvent evaporation technique. Hydrophilic polymers HPMC E5 LV and MCC were used to prepare solid dispersions (SD) of ATC by rota evaporation method in 1:1 and 1:2 ratio and by physical mixture in the ratio of 1:2. Solid dispersions obtained by both methods were characterized by solubility studies, scanning electron microscopy (SEM). SEM analysis inferred that the pure drug was crystalline while the drug in SD was in amorphous form. Drug release from SD prepared by solvent evaporation method was found increasing with increasing concentration of the polymer. Drug release from the SD of drug with MCC 1:1 and 1:2 ratio was 79.7% and 91.8% respectively and for SD of drug with HPMC 1:1 and 1:2 ratio was 86.4%, 98.3% respectively and for the dispersions prepared by physical mixture of drug and MCC, drug and HPMC in 1:2 ratio was 54.9% and 59.3% respectively. Tablets prepared by the SD of ATC and HPMC 1:2 ratio showed maximum percentage drug release (98.3%). By fitting the release data into various models, F4 batch was found to follow zero order release pattern. Stability study was performed as per ICH guidelines and all formulations were found to be stable. Optimized formulation compared with marketed product was found bioequivalent.

Keywords: Atorvastatin calcium, HPMC E5 LV, Solubility, Bioavailability, Rota