Formulation Development and In-Vitro Evaluation of Extended Release Tablets Containing Losartan Potassium

The objective of the present work was to prepare and evaluate extended release matrix tablets of Losartan potassium. Losartan potassium, an Angiotensin receptor blocker used in the treatment of hypertension, has poor bioavailability (33%) and has elimination half-life of 2 hrs. So, it is best suited for extended release matrix formulation. The tablets were formulated to reduce the frequency of dose administration and to improve the patient compliance. Tablets were prepared by direct compression method, using hydrophilic polymers like natural (Xanthan gum, Guar gum) and synthetic (HPMC K100 M) as the release retarding polymers. The FTIR studies indicated the absence of drug polymer interaction. The formulated tablets were evaluated for weight variation, hardness, friability, drug content uniformity and swelling index. The In Vitro drug release of the tablets was carried out in pH 6.8 buffer for 24 hrs. The influence of different polymers like Xanthan gum, Guar gum and HPMC K100 M as well as their combinations on the drug release profile was studied. Based on the dissolution studies optimised formulae are F-12 and F-14. To analyze the mechanism of drug release from the tablets, the In-Vitro dissolution data of optimised formulations were fitted to zero order, first order, higuchi release model and korsmeyer-peppas model based on regression coefficient. The n values of the optimised formulations F-12 and F-14 were 0.585 and 0.599 respectively. This indicates the release of drug followed Non Fickian or anomalous transport.