The growing demand for safe, effective, and high-quality pharmaceutical formulations necessitates the development of reliable analytical methods for drug estimation and quality control. Nimesulide and Diclofenac are widely used non-steroidal anti-inflammatory drugs (NSAIDs) frequently formulated in combination to achieve enhanced therapeutic efficacy through synergistic action. The simultaneous estimation of these drugs in pharmaceutical dosage forms is therefore essential for ensuring product quality, safety, and regulatory compliance. This review focuses on UV–Visible spectrophotometric methods developed for the simultaneous estimation of Nimesulide and Diclofenac. UV spectroscopy is widely preferred in pharmaceutical analysis due to its simplicity, rapidity, cost-effectiveness, and minimal requirement for complex instrumentation. The technique is based on the absorption of ultraviolet radiation by drug molecules, following Beer–Lambert’s law, which establishes a direct relationship between absorbance and concentration within a defined linear range. Typically, Nimesulide exhibits maximum absorbance (λmax) around 390–395 nm, while Diclofenac shows λmax near 275–280 nm, enabling their simultaneous quantification. Various analytical approaches have been employed for simultaneous estimation, including the simultaneous equation method, absorbance ratio method (Q-analysis), and derivative spectrophotometry. The simultaneous equation method utilizes absorbance measurements at two selected wavelengths to calculate the concentration of each drug. The Q-analysis method involves the use of an isoabsorptive point along with the λmax of one component, offering improved accuracy and simplicity. Derivative spectroscopy enhances spectral resolution and selectivity, particularly in cases of overlapping spectra, thereby minimizing interference. Method validation is performed in accordance with International Council for Harmonization (ICH Q2(R1)) guidelines to ensure reliability and reproducibility. Key validation parameters include linearity, accuracy, precision, limit of detection (LOD), limit of quantification (LOQ), robustness, and specificity. Reported methods demonstrate excellent linearity within concentration ranges of 5–30 µg/mL, with correlation coefficients exceeding 0.999. Accuracy is confirmed through recovery studies (98–102%), while precision is indicated by relative standard deviation values below 2%. LOD and LOQ values confirm adequate sensitivity, and robustness studies indicate minimal impact of small variations in analytical conditions. A review of the literature reveals that UV spectrophotometric methods provide consistent, accurate, and reproducible results for routine analysis of Nimesulide and Diclofenac in pharmaceutical formulations such as tablets and capsules. Although these methods are less sensitive than advanced chromatographic techniques, their simplicity, rapid analysis, and cost-effectiveness make them highly suitable for routine quality control applications.
Gaurav Bhausaheb Gayakwad* (Mon,) studied this question.