Development and Validation of RP-HPLC method for simultaneous estimation of Methyldopa and Hydrochlorothiazide in Pharmaceutical Dosage Form

INTORDUCTION Methyldopa is (2S)-2-amino-3-(3, 4dihydroxyphenyl)-2-methylpropanoic acid (figure1a). Hydrochlorothiazide is 6-chloro-1, 1-dioxo-3,4dihydro-2H-1,2,4-benzothiadiazine-7-sulfonamide (figure1b). Methyldopa and Hydrochlorothiazide are official in Indian Pharmacopoeia and U.S. Pharmacopoeia, but there is no official method for the combination. Both drugs in combination of tablet dosage form in the ratio of 250:25 mg Methyldopa and Hydrochlorothiazide respectively. The formulation of Methyldopa and Hydrochlorothiazide is available with trade name Aldoril-25, the medication is used to treat high blood pressure (hypertension). Lowering high blood pressure helps in preventing strokes, heart attacks and kidney problems. Methyldopa works by relaxing blood vessels so blood can flow more easily. Hydrochlorothiazide is a "water pill" (diuretic), it increases the urine output and helps to relax the blood vessels so that blood can flow more easily. A few methods have been reported including response surface methodology [3], HPLC [4, 5]. With this present proposed method both Methyldopa and Hydrochlorothiazide estimates simple and economical in tablet formulation. EXPERIMENTAL 2.1 Chromatographic Conditions Waters e 2695 separation module with high pressure liquid chromatographic instrument provided with a Hypersil BDS C8 column (250 mm x 4.6 mm ; 5 μ ) and 2489 UV-Visible detector, auto injector, auto sampler with Empower 2 software from Waters corporation, Milford USA was employed in the study. 2.2 Chemicals and Reagents HPLC grade acetonitrile, and Potassium dihydrogen phosphate AR Grade, Potassium Hydroxide AR grade were purchased from SD Fine Chem Mumbai, India were used in the study, reference samples were obtained from M/s. Bio-Leo Analytical Labs India Pvt Ltd, Hyderabad, India, and the formulation samples were purchased from local market. 2.3 Preparation of Mobile phase Research Article