R. Rambabu

The simple, sensitive, reliable and economically new method was developed for the estimation of Ramipril (RAM) and Telmisartan (TEL) by RP-HPLC in combined dosage form. After several trials with the different combinations and ratios of solvents, the present chromatographic parameters were optimized. It was found that potassium dihydrogenphosphate (pH 3.0): methanol: acetonitrile (30:20:50 v/v/v) was given satisfactory results. A C18 column (Agilent ODS UG 5 column) having dimensions of 4.5mmx250mm was used. The mobile phase was pumped at a flow rate of 1.0ml/min and the eluents were monitored at 210nm. System suitability was carried out by injecting six replicate injections of 100% standard concentration, number of theoretical plates, HETP(height equivalent Theoretical plate) and resolution were satisfactory. The optimized chromatograms confirm the presence of Ramipril and Telmisartan at Rt: 4.1 min and Rt: 5.11min respectively without any interference. The concentration range of 1-5µg/ml for RAM and 8-40µg/ml for TEL were linear with correlation coefficients 0.999 and 0.989 respectively. The percent recovery studies were found to be 99.5-99.88% and 99.93-99.99% w/w for RAM and TEL respectively which indicate method was accurate. The proposed method was precise and reproducible with %RSD of 0.93 for Ramipril and 0.41 for Telmisartan, respectively. The limits of detection and limits of quantification were 0.10µg/ml and 0.25µg/ml for Ramipril 0.32µg/ml and 0.78µg/ml for Telmisartan, respectively. The method was found to be robust and ruggedness and was well suitable for the estimation of commercial formulations of selected combinations.