Mohammad Firoz Khan

Theoretically Guided Analytical Method Development and Validation for the Estimation of Rifampicin in a Mixture of Isoniazid and Pyrazinamide by UV Spectrophotometer

A simple, rapid, economic, accurate, and precise method for the estimation of rifampicin in a mixture of isoniazid and pyrazinamide by UV spectrophotometeric technique (guided by the theoretical investigation of physicochemical properties) was developed and validated. Theoretical investigations revealed that isoniazid and pyrazinamide both were freely soluble in water and slightly soluble in ethyl acetate whereas rifampicin was practically insoluble in water but freely soluble in ethyl acetate. This indicates that ethyl acetate is an effective solvent for the extraction of rifampicin from a water mixture of isoniazid and pyrazinamide. Computational study indicated that pH range of 6.0–8.0 would favor the extraction of rifampicin. Rifampicin is separated from isoniazid and pyrazinamide at pH 7.4 ± 0.1 by extracting with ethyl acetate. The ethyl acetate was then analyzed at λmax of 344.0 nm. The developed method was validated for linearity, accuracy and precision according to ICH guidelines. The proposed method exhibited good linearity over the concentration range of 2.5–35.0 μg/mL. The intraday and inter-day precision in terms of % RSD ranged from 1.09 to 1.70% and 1.63 to 2.99%, respectively. The accuracy (in terms of recovery) of the method varied from of 96.7 ± 0.9 to 101.1 ± 0.4%. The LOD and LOQ were found to be 0.83 and 2.52 μg/mL, respectively. In addition, the developed method was successfully applied to determine rifampicin combination (isoniazid and pyrazinamide) brands available in Bangladesh.

A Simple RP-HPLC Method Development and Validation for the Simultaneous Estimation of Naproxen and Rabeprazole

Article history: Received on: 06/10/2016 Revised on: 29/10/2016 Accepted on: 06/11/2016 Available online: 29/11/2016 A simple, economic, selective, accurate, precise reverse phase high performance liquid chromatographic method for the simultaneous estimation of naproxen and rabeprazole sodium in pure and pharmaceutical dosage forms was developed and validated. Naproxen and rabeprazole sodium were well separated using a phenomenex ODS C18 column of dimension 4.6 mm × 250 mm, 10 μm and mobile phase comprised of sodium dihydrogen phosphate buffer (pH 7.5±0.1) and acetonitrile in the ratio of 70:30 (v/v) at the flow rate 1 mL/min and the detection was performed at 275nm. The retention time for naproxen and rabeprazole sodium were found to be 3.33 ± 0.027 and 7.61 ± 0.043 min, respectively. The developed method was validated for specificity, linearity, precision and accuracy according to ICH guidelines. The proposed method is highly specific and linear over the concentration range of 2.0-60.0 μg/mL and 1.0-30.2 μg/mL for naproxen and rabeprazole sodium, respectively. The intraday precision (% RSD) of naproxen and rabeprazole sodium was in the range of 0.39 1.88% and 0.20 -1.51% while the interday precision ranged from 0.08 1.34% and 0.73 -0.87%, respectively. The accuracy (in terms of recover) of the method varied from 99.4-104.2% and 98.1-100.6% for naproxen and rabeprazole sodium, respectively. The LOD and LOQ of naproxen and rabeprazole sodium were found to be 0.6 and 0.1 μg/mL and 1.7 and 0.4 μg/mL, respectively. The sample solutions were stable for at least three hours. However, the developed method was successfully applied to assay naproxen and rabeprazole sodium brands available in Bangladesh.