A precise and accurate method for the analysis of antihypertensive drug combination nifedipine and valsartan was developed using the HPTLC method. The stationary phase used was a precoated silica gel G60-F 254 aluminium sheet and the mobile phase was acetonitrile: methanol: n-butanol: acetic acid (6:2:2:0.1, v/v/v/v). The detection of spots was carried out densitometrically using a UV detector at 230 nm in the absorbance mode. The Rf values of valsartan and nifedipine were found to be 0.25 and 0.65, respectively. The calibration curve was found to be linear in the range of 120-320 ng/band and 900-2400 ng/band for nifedipine and valsartan, respectively. Forced degradation studies were performed using stress conditions like acid and base hydrolysis, photolytic, thermal and oxidative stress degradation to develop the stability indicating method. The degradation study indicated that nifedipine was susceptible to acid-base hydrolysis, oxidative stress degradation and photolytic degradation, while valsartan was susceptible to acid-base hydrolysis and oxidative stress degradation.

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A specific, accurate, precise, and reproducible liquid chromatographic method has been developed and validated for the estimation of acamprosate calcium and baclofen in combination. The separation was achieved using stationary phase Phenomenex C18 column (150 mm× 4.6 mm.) in isocratic mode, with mobile phase containing 0.05 M potassium dihydrogen orthophosphate buffer (pH 7) : acetonitrile (10:90 V/V), at a flow rate of 1.0 mL/min and effluents were monitored at 210 nm. The retention time of acamprosate calcium and baclofen were found to be 1.9 min and 5.3 min, respectively. The linearity for acamprosate calcium and baclofen were in the range of 2-64 µg/mL and 1.2- 38.4 µg/mL, respectively. The method was validated as per ICH guideline. The recoveries of Acamprosate calcium and baclofen were found in the range of 98.90 - 100.13 % and 98.60 -100.02 %, respectively. The method was successfully applied for the determination of both the drugs in combination.