Evaluation and Characterization of Losartan and Hydrochlorothiazide fixed dose as Gastroretentive bilayered floating tablets

Abstract

Losartan potassium (LSP) is a potent, highly specific angiotensin II type 1 (AT1) receptor antagonist with antihypertensive
activity. It is readily absorbed from the gastrointestinal tract with oral bioavailability of about 33% and a plasma elimination
half-life ranging from 1.5 to 2.5. Hydrochlorothiazide is a thiazide diuretic and is used in the treatment of mild to moderate
hypertension. It is very slightly soluble in water having plasma half life of 6h to 14h. Therefore an attempt was made to
increase oral bioavailability of Losartan and Hydrochlorothiazide fixed dose combination by retaining the dosage form in
stomach for longer period of time. This is achieved by developing gastroretentive floating drug delivery system. These tablets
were prepared to increase the bioavailability of the drugs by utilizing the drugs to full extent avoiding unnecessary frequency
of dosing and subsequently first pass metabolism.