In Vitro - In Vivo Evaluation Of E/R Trilayer Matrix Tablets Containing Solid Dispersion Of Atorvastatin

Investigation of  in vitro/in vivo  behaviour of extended release tablets containing solid dispersions of Atorvastatin is the focus of the present research work. Atorvastatin trilayer matrix tablets were prepared by direct compression method and consisted of middle active layer with different grades of hydroxypropylmethylcellulose (HPMC), ethyl cellulose and Carbopol 934P. Barrier layers are prepared with hydrophobic polymers carnauba wax and xanthan gum. Based on the evaluation parameters, drug dissolution profile and release order kinetics HF16 was found to be optimized formulation. The developed drug delivery system provided prolonged drug release rates over a period of 24 h. The release profile of the optimized formulation (HF16) was described by the Zero-order and best fitted to Higuchi model. FTIR confirmed that there was no chemical interaction between drug and excipients used in the formulation. . In vivo bioavailability studies were conducted for optimized formulation HF16 and reference standard. The optimized formulation of Atorvastatin trilayer matrix tablet was shown significant plasma concentration with extended release and maintained for 24 hrs with patient compliance by reducing the dosage frequency, when compared with reference standard.