Development and validation of spectrophotometric and spectrofluorimetric methods for determination of cilnidipine

Abstract

Purpose: To develop simple and reliable quantitative methods for the determination of cilnidipine (CLD) in pharmaceutical tablets. Methods: Two simple and sensitive methods (spectrophotometric and spectrofluorimetric) were developed for the determination of cilnidipine (CLD) in pure form and in a pharmaceutical preparation. Spectrophotometric method (A) is based on oxidation of CLD with a known excess amount of N-bromosuccinamide (NBS) in acidic medium, followed by addition of methyl orange indicator and absorbance measurement at 510 nm. The spectrofluorimetric method (B) is based on oxidation of CLD to cerium (IV), followed by measurement of fluorescence emission of Ce (III) at 350 nm. Factors that affect the performance of the two methods were studied and optimized. Results: The spectrophotometric and spectrofluorimetric procedures were successfully used for measuring CLD levels in pharmaceutical dosage form, in the ranges of 2.0 - 25.0 and 0.25 - 11.2 µg/mL, at detection limits of 1.05 and 0.13 µg/mL, respectively. There were no significant differences between the proposed methods and a standard reference method (p < 0.05). Conclusion: The developed methods provide simple and reliable procedures for quantitative measurement of CLD in bulk and tablet forms.