الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Losartan potassium (LP) is an orally active, non-peptide angiotensin II receptor antagonist used for treatment of hypertension. It acts as a specific AT1 receptor blocker resulting in a reduction in the pressor impact of angiotensin II. It is also prescribed to control heart failure, especially in patients who suffer from cough with angiotensin converting enzyme (ACE) inhibitors. Moreover, it is used to minimize stroke risk in patients who have hypertrophy in the left ventricle, and in the remedy of diabetic nephropathy and myocardial infarction. Losartan potassium (LP) was considered as class III drug in accordance with the Biopharmaceutical Classification System (BCS). Drugs belonging to BCS class III show high solubility and low permeability. Since the rate of dissolution of these drugs is fast, permeability through biological membranes is the slowest step (rate limiting) for drug absorption. LP is well absorbed from gastrointestinal tract after oral administration with maximum plasma concentrations (Cmax) occur within 1-2 hours after taking an oral dose. The systemic bioavailability of orally taken LP is low and poor (23 to 30 %) which is attributed to that LP is extensively metabolized in liver. The oral delivery of Losartan Potassium shows some drawbacks which limit its application in therapy. The most popular drawbacks are poor and variable oral bioavailability, poor patient compliance particularly in geriatric patients, short elimination half-life (2hr) which requires repeated administration to keep its plasma concentration level within the required therapeutic range.