Quantification of Common Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) in their Fixed-Drug Combinations (FDCs) with Paracetamol Using UV Spectrometry and Simultaneous Equation Method

NSAIDs (Non-Steroidal Anti-Inflammatory Drugs) are commonly prescribed analgesics, antipyretics and anti-inflammatory drugs. They are widely consumed in generic form both with and without prescriptions. Their quantification in supplied and marketed medications is important to ensure efficacy and avoid overdosage in patients. We used UV-Visible spectroscopy to quantify commonly used seven NSAIDs. 4 of the NSAIDs namely, aceclofenac, diclofenac, ibuprofen, mefenamic acid were also quantified in their fixed-drug combinations (FDCs) with paracetamol while aspirin and naproxen were quantified in laboratory prepared mixtures. All drugs exhibited a linear response in the range of 5-25 ppm. Linear regression studies were performed and R2 values were found to greater than 0.999. The LOD and LOQ values for all drugs were low enough to establish good method sensitivity. According to the repeatability studies, % RSD values for all drugs were less than 2% which is well within the ICH limits of % RSD ≤ 5%. For the simultaneous quantification of each NSAID with paracetamol, the mean % recovery values for each of the drugs in combination were found to be satisfactory and the performance of the method was evaluated through assays of marketed formulations of different brands of the drugs. The method effectively differentiated and quantified individual NSAIDs within their FDCs. It gave reliable results with acceptable linearity, sensitivity, precision, and accuracy. The method can be utilized in resource limited settings to perform quantification of these drugs in mixed formulations. Further, it can be modified and validated to analyse mixtures of drugs of other classes.