Simultaneous Determination of Amlodipine Besylate and Atorvastatin Calcium in Pharmaceutical Tablet Formulation by Derivative Spectrophotometric Method

Two simple, accurate and precise methods viz. first derivative zero crossing spectrophotometry (method 1) and derivative ratio spectra zero crossing method (method 2) have been developed for simultaneous determination of amlodipine besylate and atorvastatine calcium in pure and commercial formulation without any prior separation or purification. The linearity range was found to be 5–40 μg ml⁻¹ for both the drugs. The value of limit of detection and limit of quantification was 0.397 μg ml⁻¹ and 1.323 μg ml⁻¹ for amlodipine and 0.220μg ml⁻¹ and 0.735 μg ml⁻¹ for atorvastatine respectively for method 1 and 0.600 μg ml⁻¹ and 0.262 μg ml⁻¹ for amlodipine and 0.262μg ml⁻¹ and 0.874 μg ml⁻¹ for atorvastatine respectively for method 2. The method was satisfactorily validated in terms of accuracy and precision. The results of the study showed that the proposed spectrophotometric methods are useful for the routine determination of amlodipine and atorvastatin in its combined pharmaceutical tablet dosage form.