First-order derivative spectrophotometric method for simultaneous determination of brinzolamide and timolol maleate in ophthalmic formulation

Abstract

Multi-analyte determination techniques are favored over those that can only determine a single analyte at a time because they enable resource savings (cost, time, and solvents) and reduce generated waste and the number of samples required for analysis. This research presents a novel method for the simultaneous determination of brinzolamide (BRZ) and timolol maleate (TML) in pharmaceutical ophthalmic preparations using first-order derivative UV–Visible spectroscopy. The proposed approach is environmentally friendly and yet to be previously reported in the literature. In this approach, the peak amplitude of BRZ was quantified at the zero-crossing point of TML, i.e., 248.80 nm, whereas TML was determined by measuring absorbance at 297.60 nm. The developed method was validated according to the International Council for Harmonisation guidelines Q2(R1). The developed method was linear with excellent correlation coefficient values (R2 > 0.9998) in the range of 4 – 24 µg/ml for BRZ and 5 – 25 µg/ml for TML. The accuracy and precision results were within limits for both the analytes (%Relative standard deviation, RSD <2 %). The proposed method demonstrated LOD = 0.38 µg/mL for BRZ and 0.98 µg/mL for TML; LOQ = 0.91 µg/mL for BRZ and 2.99 µg/mL for TML), and was found to be selective, and robust. Lastly, the novel Analytical GREEnness (AGREE) metrics, the analytical eco-scale, and the green analytical procedure index (GAPI) were utilized to evaluate the developed technique's environmental sustainability and compare it to the HPLC method.