Development and Validation of Novel Simultaneous Equation and Absorbance Ratio Method for Simultaneous Estimation of Telmisartan and Azelnidipine for Bulk and Pharmaceutical Dosage form using UV Spectrophotometry

The telmisartan and azelnidipine are the drugs used in combination for the treatment of hypertension. Telmisartan is an angiotensin II receptor blocker and azelnidipine is a calcium channel blocker, together in combination they reduce the augmentation index. For this combination, the author developed novel analytical methods like the simultaneous equation method and absorbance ratio (Q) method for simultaneous estimation of telmisartan and azelnidipine by UV spectrophotometry using methanol: distilled water (50:50) as a solvent. The maximum absorption was found 295±1 nm and 255±1nm for telmisartan and azelnidipine respectively; the isosbestic point was found at 275±1nm. Both methods were linear in the range of 2-12µg/ml for telmisartan and 6-16µg/ml for azelnidipine. Different validation parameters of both methods were validated as per the International Conference on Harmonization guidelines. The results found were statistically analyzed and validated which were found within the range (%RSD ≤ 2). These developed and validated methods were found to be reliable and reproducible. Hence it can be used for simultaneous estimation of telmisartan and azelnidipine in bulk and combined dosage form.