RP-HPLC.

A new simple fast accurate and economical reverse phase high performance liquid chromatographic method was developed for the determination of Ramipril and Olmesartan in bulk and tablet dosage form. The separation was eluted on a Inertsil C8 column (100 mm x 4.6 mm; 5µ) using a mobile phase mixture of mixed phosphate buffer 6.8 and acetonitrile in a ratio of 65:35 v/v at a flow rate of 1.0ml/min. The detection was made at 219 nm. The retention times were 2.28min for Ramipril and 3.76min for Olmesartan. Calibration curve was linear over the concentration range of 2.5-15 µg/ml for Ramipril and 10 to 60 µg/ml for Olmesartan. The propose method was validated as per the ICH guidelines parameters like Linearity, specificity, precision, accuracy, robustness and ruggedness. The method was accurate, precise, specific and rapid found to be suitable for the quantitative analysis of the drug and dosage form.

A reverse phase high performance liquid chromatographic method was developed for the determination of Mirabegron in bulk and Pharmaceutical dosage form. The separation was effected on a Waters ODS C18 column (150 mm x 3.9 mm;5µ) using a mobile phase mixture of buffer and acetonitrile in a ratio of 50:50 v/v at a flow rate  of 1ml/min. The detection was made at 249 nm. The retention time of Mirabegron was found to be 2.502 min.  Calibration curve was linear over the concentration range of 6.25-37.5 µg/ml of Mirabegron. The propose method was validated as per the ICH guidelines. The method was accurate, precise, specific and rapid found to be suitable for the quantitative analysis of the drug and dosage form.

A reversed phase high-performance liquid chromatographic method was developed and validated for the quantitative determination of two antiviral drugs viz. lopinavir and ritonavir. Chromatography was carried out by gradient  technique on a reversed-phase C18 Column, Phenomenex (250 x 4.6 mm, 5 µ) with mobile phase mixture of Buffer: Acetonitrile (45:55 v/v) was used as a mobile phase and the pH was adjusted into 4.5 by using with O-phosphoric acid, at a flow rate of 1.2 ml/min. The UV range was detected at 240nm for lopinavir and ritonavir respectively. The different analytical performance parameters such as linearity, precision, accuracy, and specificity, limit of detection (LOD) and limit of quantification (LOQ) were determined according to International Conference on Harmonization ICH Q2B guidelines. The linearity of the calibration curves for each analyte in the desired concentration range is good (r2 >0.9). The recovery of the method was between 102.1% and 100.1% for lopinavir and ritonavir respectively. Hence the proposed method is highly sensitive, precise and accurate and it successfully applied for the reliable quantification of API content in the commercial formulations of lopinavir and ritonavir. Key words: Lopinavir, Ritonavir, UV spectrophotometry, RP-HPLC.