# I. Introduction rug is a substance that brings about a change in the biological functions through its chemical actions. Losartan are the first marketed blockers of the angiotensin II-type receptor (non peptide, orally active, and competitive antagonist of AT1 receptor) [1]. Its wavelength is 234nm which lies in the UV range i.e. 200-380nm. It is the prototypic ARB. Their pharmacologic effects are very similar to the ACE inhibitors, because they also produce the arteriolar and venous dilation and block aldosteron secretion, thus lower the blood pressure, decreases the salt and water retention. They have no effect on bradykinin levels and metabolism [2]. They decrease the nephrotoxicity of diabetes and making attractive therapy in hypertensive diabetics. They also provide benefit in patient with heart failure and chronic kidney disease. The adverse effects are also similar to ACE's inhibitors, but the risk of cough and angioedema is decreased because it has no effect on bradykinin levels ARB's are fetotoxic and should not be used by women who are pregnant, it is contraindicated during pregnancy [3]. Losartan belong to antihypertensive therapeutic class. It blocks the receptor also called angiotensin II receptor blocker (ARBs). Losartan is specific or selective type I angiotensin II receptor (AT1) antagonist. They block receptor as a result decrease in blood pressure (rennin-angiotensin-aldosteron system) RAAS [4]. Losartan inhibit the binding of angiotensin II to type I in tissue (kidney and adrenal glands). Losartan and its active metabolitesE-3174 is more potent then losartan inhibition (angiotensin II to type I) cause vasodilation (normally AT1?vasoconstriction + aldosteron) decrease sodium and water retention and increases excretion [5]. The formula of losartan is C 22 H 23 CIKN 6O .Losartan is given orally and it is well absorbed but undergo first pass metabolism. Systemic bioavailability is 33 after metabolism it is highly protein bound and while taking the food with medicine decreases its absorption. In healthy individual it distributes about 34l and its metabolite about 12l. It is metabolized in liver by an enzyme CYP450, 2C9 and 3A4 and converts into an active metabolite 5 carboxylic acid derivatives (E-3174). It is administered orally so 35% excreted in urine and about 60% excretion in feces. When administer by IV route then 45% of drug is excreted in urine and 50% drug in feces [6]. Protein binding of losartan is 99.7% (primarily albumin) and bioavailability is 25-35%. [7]. The appearance of losartan potassium is white to off white crystalline powder its melting point is between 263-265C and it is freely soluble in water. Molecular mass of losartan potassium is 462.01 [8]. Its indications are: mild to severe hypertension, diabeticnephropathy reducing risk of stroke in people with heart disease [9]. Its adverse effect include: losartan worsens the condition the patients who had a history of PD, in the form of several falls and episodes of freezing and severe bradykinesia. So, its combination with levodopa or carbidopa should be avoided [10]. Hypergranulosis and hyperkeratosis be developed during its treatment with losartan for arterial hypertension. Long term of losartan potassium develops angioedema. It triggers psoriasis and generalized bullous lesions and patients can develop Steven-Johnson syndrome and renal impairment during the treatment of hypertension with losartan [11]. Losartan potassium is contraindicated in pregnancy because it is fetotoxic and cancause mal formation of the fetus and even leads to death and it is also contraindicated for renal impaired function and bilateral renal artery stenosis [12]. Drug-Drug interactions of losartan potassium with fluconazol rises the plasma level of losartan, indomethacin blunt its antihypertensive effect, concomitant use of potassium supplement may lead to increase in serum potassium, rifamycin may reduce the antihypertensive effect, and increase in lithium may increase its adverse effects [13]. Drug food interactions of losartan potassium with grapefruit which decreases its active metabolites so reducing the efficacy, drinking alcohol can further lower B.P and may increase certain side effects [14] # II. Methodology a) Material Distilled water, losartan potassium tablets standard and sample, glass rod, mortar and pestle, measuring cylinder, tissue paper, weigh balance and UV visible spectrophotometer. # b) Method ? Wash the apparatus (beakers, glass rod, conical flask, mortar and pestle, measuring cylinder) and rinsed with freshly prepared distilled water.Dry all the apparatus.Now weight the tablets accurately.Crush the tablets in mortar and pestle.Transfer the 0.2mg of calculated amount of drug into 100ml of beaker andmake up the volume with freshly prepare distilled water.Note down the absorbance of standard solution and sample solution separately at 234nm wavelength by using UV visible spectrophotometer. ? Calculate the % assay with the help of formula [15]. Each tablet of 100mg or 0.1gm 0.1gm -----------------0.175gm 0.1gm ---------------0.2475gm 0.2gm -----------------0157×0.1/2=0.314gm 0.2gm ---------------0.2475×0. Losartan potassium # III. # Observations and Calculations # Standard # IV. Result We have performed the assay of losartan potassium by using UVvisible spectrophotometer, and the calculated % assay of losartan potassium is 98% [16]. # V. Discussion The aim of the study was to carry out the pharmaceutical assay on different brands of losartan potassium by using spectrophotometer. This results shows that absorbance is directly proportionto concentration so, it is obeys to Beers lambert law and assay of all brands are within range of USP and British pharmacopeia linearity given in figure1.We have done these types ofassay for different brand which helpful for selecting drugs [17]. ![Sample Weight of tablet 1=0.158gm Weight of tablet 1=0.248gm Weight of tablet 2=0.156gm Weight of tablet 2=0.247gm Average: 0.158+0.156/2=0.157 Average: 0.248+0.247/2=0.2475gm Each tablet of 100mg or 0.1gm](image-2.png "") © 2015 Global Journals Inc. (US) * Lippincott's illustrated reviews pharmacology MAClark RFinkel JARey Whalen K Lippincott Williams and Wilkins 2012 228 236 antihypertensive. wolters kluwer business. Edition (5 th * Basic and clinical pharmacology BGKatzung SBMasters ATrevor 2012 185 antihypertensive agent. Lange medical publications, e (12 th * pharmacoeconomics of angiotensin II antagonist in type 2 diabetic patients with nephropathy": implications for decision making CBoersma .JAtthobari RGansevoort DeJongvan Den Berg LDe Jong PDe Zeevw DEtal Pharmacoeconomics" 24 6 2006 * Pharm-d, wake forest university school of medicine JulienneKKirk Amfam physician 59 June 1999 II * Angiotensin II receptor antagonists role in arterial hypertension RafaelHernández-Hernández Apr 27. 2014 * Development and Validation of Kinetic Spectrophotometric Method for the Determination of Losartan Potassium in Pure and Commercial Tablets Journal of the Chinese Chemical Society Nafisur Rahman, Masoom Raza Siddiqui and Syed Najmul Hejaz Azmi June 2006 * A Review of its Pharmacology, Clinical Efficacy and Tolerability in the Management of Hypertension KarenLGoa AntonaJWagstaff Drugs 51 5 May 1996 * Formulation and Evaluation of Sustained Release Matrix Tablets of Losartan potassium SShanmugam RamyaChakrahari * KSundaramoorthy TAyyappan TVetrichelvan International Journal of PharmTech Research 3 1 Mar 2011 * MBarry MDBrenner EMark MDCooper DPh MDDick De Zeeuw DPh FWilliam * Effects of Losartan on Renal and Cardiovascular Outcomes in Patients with Type 2 Diabetes and Nephropathy MKeane The New England Journal of Medicine 345 Sep 2001 * A Review of its Pharmacology, Clinical Efficacy and Tolerability in the Management of Hypertension KarenLGoa AntonaJWagstaff Drugs 51 5 May 1996 * BGeorge Pylypchuk ACE Inhibitor-Versus Angiotensin II Blocker-Induced Cough and Angioedema 32 October 1998 Annal of Pharmacotherpy. * Angiotensin II receptor antagonist treatment during pregnancy, Clinical and Molecular Teratology SAlwan * JEPolifka JMFriedman 10.1002/bdra.v73:2/issuetoc February 2005 73 * Drug-interactions and adverse effects of losartan potassium, an angiotensin II receptor antagonist KYoshinaga Japanese Journal of Clinical Medicine 57 5 1999 * DomenicASica Clinical Pharmacokinetics of Losartan 44 8 August 2005 Clinical Pharmacokinetics * Zehra ashraf and Tasleem mukhtar, assay of different brands of cefadroxil by using spectrophotometric method Safila naveed 2015 14 * Assay of Pioglitazone HCL by Using UV Visible Spectrophotometer SafilaNaveed ZehraAshraf TasleemMukhtar British Journal of Research 2015 * Zehra ashraf and Muhammad tanweer alam, using UV spectrophotometric method to determine the linearity of vildagliptin brands Safila naveed 2015 * US) Guidelines Handbook Global Journals Inc 2015