A Novel, selective, accurate and rapid Reversed Phase High Performance Liquid Chromatographic (RPHPLC) method for the analysis of Efonidipine Hydrochloride Ethanolate and Telmisartan in binary mixture has been developed and validated. The chromatographic system consisted of a Phenomenex Kinetex ® 5µ C18 Size: 150 * 4.6mm column and the separation was achieved by using ambient temperature with a mobile phase containing mobile Phase Acetonitrile:25mM Phosphate Buffer pH 4.9 (45:55). The samples were monitored at 253 nm for detection at a flow rate of 1.0 mL/min and the retention time was about 7.77 and 4.10 mins for Efonidipine Hydrochloride Ehanolate and Telmisartan respectively. The calibration curve was linear over the concentration range 5-30 and 10-60 ?g/mL for Efonidipine Hydrochloride Ehanolate and Telmisartan respectively. The proposed method is accurate in the range of 99.75% - 100.10% recovery and precise (%RSD of intraday variation and % RSD of inter day variation were found to be within the acceptance criteria). Therefore, this method can be used as a more convenient and efficient option for the analysis of Efonidipine Hydrochloride Ehanolate and Telmisartan in Quality control laboratory.

Efonidipine hydrochloride ethanolate and telmisartan combination is used for to treat hypertension treatment and under clinical phase 4 study. It is necessary to develop suitable quality control methods for rapid and accurate determination of these drugs. Three simple, accurate, sensitive, precise and economical UV spectrophotometric methods (A, B &, and C) have been developed for simultaneous estimation of efonidipine hydrochloride ethanolate and telmisartan in their synthetic mixture. Method (A) is based on the first order derivative spectrophotometric method at zero crossing wavelength. In this method the zero crossing zero-crossing point of efonidipine hydrochloride ethanolate is 326 nm and for telmisartan is 272 nm. The linearity was obtained in the concentration range of 8-20 μg/ml for efonidipine hydrochloride ethanolate and 16-40 μg/ml for telmisartan using methanol as a solvent. Method (B) is based on absorbance correction method, method; it was performed at 347 nm for efonidipine hHydrochloride ethanolate and at 296 nm for telmisartan. Method (C) is based on dual wavelength method developed using absorbance difference at 242.5 nm and 257.5 nm for efonidipine hydrochloride ethanolate and 244.5 nm and 287 nm for telmisartan. The accuracy and precision of the methods were determined assessed and validated statistically. All the methods showed revealed good reproducibility and recovery. The three methods were compared using one way ANOVA. All methods were found to be rapid, specific, precise and accurate and these methods require no preliminary separation and found no interferences from the tablet excipients so it can be used for routine analysis of both drugs in quality control laboratories.

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