Enhancement in Dissolution Rate of Atorvastatin Trihydrate Calcium by Formulating Its Porous Tablet Using Sublimation Technique

Objective Proposed study was aimed to formulate and evaluate atorvastatin trihydrate calcium porous tablet. Methods Since atorvastatin trihydrate calcium is highly unstable drug and is immensely susceptible to hydrolysis and oxidation process, sublimation technique is taken into account for preparing porous tablet by using direct compression technique. Excipient screening and pre-formulation study was conducted to evaluate the presence of drug-excipient compatibility. Formulation was optimised using central composite design (CCD) and optimized batch was further characterised by scanning electron microscopy (SEM) for identification of surface topography. Optimized formulation was also characterised with respect to FTIR, TGA analysis, compression analysis, in vitro drug release studies and stability studies. Results Hardness, friability, disintegration time and drug content of optimized porous tablets were found to be 3.46 kg/cm(2), 0.92%, 7.23 s and 97.00%, respectively. Compression analysis showed optimized formulation powder is soft and plastic in nature. Tensile strength studies revealed that the tensile strength increases with increase in compression pressure. SEM studies confirmed the presence of number of pores with less than 10 mu m pore size. FTIR and TGA studies confirmed that there is no change in chemical structure of drug even in porous tablet. Prepared porous tablets released 85.06 +/- 15.55% of drug in 25 min whereas immediate release marketed tablets and pure drug released only 59.13 +/- 4.78% and 11.36 +/- 2.90% of drug in a same time. The release of proposed dosage form was substantially greater than the marketed product. Preliminary profile of stability studies did not show any significant change (p > 0.05) in the results after 90 days. Conclusion Porous tablets improved release rate which confirmed that this approach may be useful to enhance the dissolution rate of atorvastatin trihydrate calcium.