Coupling several spectral manipulations with isosbestic approach to resolve overlapped spectra for concurrent analysis of lamivudine/tenofovir combination: Evaluating environmental sustainability

Abstract

Acquired immunodeficiency syndrome (AIDS) is a chronic disease caused by the human immunodeficiency virus (HIV), which can severely damage the immune system. Recently, lamivudine (LAM) and tenofovir disoproxil fumarate (TDF) were co-formulated for the management of (AIDS). This work proposes three new UV spectrophotometric approaches based on the isosbestic point, namely: absorption subtraction method (AS), amplitude modulation method (AM) and amplitude summation method (A-Sum). The (AS) approach is based on the absorption factor method, and the two drugs can be determined at the isosbestic point in the range's zero order absorption spectra (224 nm). The (AM) method is utilizing normalized spectrum of LAM (1 μg/mL) as a divisor spectrum. After division, LAM and TDF can be determined at the isosbestic point that remained in the obtained ratio spectra at the same point even after division (224 nm). In (A-Sum) method, first order derivatization is done and the two drugs can be detected at the isosbestic point (276 nm) by using amplitude factor. The linear ranges for LAM and TDF were 5–30 μg/mL and 10–50 μg/mL, respectively. The limits of detection for LAM and TDF were 0.71–0.90 μg/mL and 0.56–1.09 μg/mL, respectively, indicating the sensitivity of these approaches. The two drugs were determined at the isospestic point without the requirement for a supplemental technique using the relevant unified regression equation. All methods were found to be accurate, repeatable, and selective based on ICH recommendations for linearity, accuracy, precision, and selectivity. The obtained results were statistically compared to the reported HPLC methods for LAM and TDF, which revealed no significant.