SIMULTANEOUS ESTIMATION OF AMLODIPINE BESYLATE AND INDAPAMIDE BY DUAL WAVELENGTH SPECTROPHOTOMETRIC METHOD FOR COMBINED PHARMACEUTICAL DOSAGE FORM

A simple, accurate, precise, rapid, economical UV spectrophotometry method, dual wavelength spectrophotometry, has been developed and validated for estimation of Indapamide (IND) and Amlodipine besylate (AML) in combined tablet dosage form and can be used in routine analysis. In this method, the absorbance at 360 nm and 256 nm of AML were same and no interference of IND at 360 nm. was observed. So, absorbance difference at 256-360 is used for estimation of IND and absorbance at 360 nm used for AML. The method was found to be linear in the concentration range of 3-18 μg/mL for IND (r2>0.99962) and 10-60 μg/mL for AML (r2>0.99969). Mean assay was found to be 99.32% and 101.34% for IND and AML respectively. In first order derivative spectrophotometry, the absorbance at 237.4 nm (ZCP of AML) and 241 nm (ZCP of IND) were used for estimation of IND and AML respectively. The method was found to be linear in the concentration range of 1.5-9 μg/mL for IND(r2=0.99983) and 5-30 μg/mL for AML(r2=0.99966). Mean assay was found to be 99.72% and 100.28% for IND and AML respectively.