Abstract
In response to the increasing demand for sustainable and high-throughput analytical approaches, this study presents the development and validation of five innovative univariate spectrophotometric methods for the simultaneous determination of amoxicillin trihydrate and diclofenac sodium in both synthetic mixtures and combined pharmaceutical dosage forms. The proposed methods, comprising first derivative, second derivative, ratio difference, ratio derivative, and ratio subtraction techniques, were designed to address the challenge of overlapping UV spectra, offering enhanced selectivity without the need for complex instrumentation or prior separation. Each method was meticulously optimized and validated in accordance with ICH Q2(R1) guidelines, demonstrating excellent linearity, accuracy, precision, and robustness. The analytical performance affirms their applicability for routine quality control of the studied drugs in a variety of formulations. Moreover, the environmental footprint of the methods was rigorously assessed using three complementary greenness evaluation tools: the GAPI, NEMI and Analytical eco scale, all of which confirmed the eco-friendly nature of the protocols. These results position the developed methods as a cost-effective, rapid, and green alternative for quality assurance in pharmaceutical laboratories, striking a valuable balance between analytical reliability and environmental responsibility.