Spectrophotometric Determination of Bisoprolol Fumarate and Levobunolol Hydrochloride in Bulk and Pharmaceutical Forms

Abstract

A very simple, accurate and rapid spectrophotometric method was developed for estimation of bisoprolol fumarate and levobunolol hydrochloride excess using Ceric Ammonium Sulphate in sulphuric acid medium as oxidant. The unreacted Ce+4have been determined using two different dyes indigo carmine and methyl orang. The coloured solutions of indigo carmine and methyl orange have maximum absorbance at 610 nm and 504 nm respectively. Different factors are studied such as time, temperature, organic solvents and sequence of addition. The effect of excipients has also been studied with non-effect absorbance found to have no effect. The methods showed a good linearity in the concentration range of (8.8– 88) μg mL-1and (19.6-45.7) μg mL-1for bisoprolol and levobunolol hydrochloride with indigo carmine and (8.8-66) μg mL-1for bisoprolol and (19.6-45.7) μg mL-1for levobunolol hydrochloride with methyl orange, with molar absorptivity and Sandell’s 1.261 x 104 L mol-1 cm1 and 0.0350 μg cm-2 for bisoprolol, 8.166 x103 L mol-1 cm1 and 0.040 μg cm-2 for levobunolol. This method in terms of LOD, LOQ, %RSD, precision accuracy, robustness and ruggedness has been validated. The calibration curves were found useful for determination of pure drug and can be applied to pharmaceutical in bulk drug and pharmaceutical preparations.