Development and Validation of Q-Absorbance Ratio UV Spectrophotometric Method for Simultaneous Determination of Bisoprolol Fumarate and Cilnidipine in Marketed Formulation Besicor C5

Abstract

Introduction: Cardiovascular disorders involve simultaneous administration of more than one drug; hence,
numerous combinations, including calcium channel blockers and beta-blockers, are available in the market and
are approved by various regulating authorities. Cilnidipine (CLD), a calcium-channel blocker, and Bisoprolol
fumarate, a β1-adrenergic receptor blocking agent are such combinations available on the market. This
combination is used in the treatment of hypertension and angina pectoris. Therefore, these drugs must be accurately
analyzed in various samples, including laboratory mixtures and marketed formulations. Methods: Simultaneous
estimation of Bisoprolol fumarate and CLD in marketed formulation Basicore C5 was carried out using the
UV spectrophotometric method in ethanol. The Q-Absorbance ratio method was selected for estimation. The
wavelengths used were 224.5 nm, λmax of Bisoprolol fumarate, and 232 nm, an iso-absorptive point of both
the drugs. Results: Beer’s law was obeyed in the concentration range between 2 and 10 μg/mL for both the
drugs. Recovery studies have validated the analysis results as per ICH guidelines. Accuracy was found between
99.3–99.75% and 99.48–100.06% for Bisoprolol fumarate and CLD, respectively. The limit of detection was
0.0943 and 0.0751 μg/mL for Bisoprolol fumarate, while 0.0355 and 0.1141 μg/mL for CLD at 224.5 and 232 nm,
respectively. The limit of quantifications was 0.2860 and 0.8983 μg/mL for Bisoprolol fumarate, while 0.1610 and
0.3457 μg/mL for CLD at 224.5 and 232 nm, respectively. Conclusion: The method was simple, reproducible,
rapid, and precise. Hence, it could analyze laboratory samples and marketed formulations containing these two
drugs.