Optimization of dispersive liquid–liquid microextraction (DLLME) and spectrophotometric analysis of sodium diclofenac in pharmaceutical formulations using Box-Behnken design (BBD)

A green and efficient Dispersive Liquid-Liquid Microextraction (DLLME) method coupled with spectrophotometry was developed and validated for the determination of sodium diclofenac in pharmaceutical samples. The method is based on the formation of an ion-pair complex to facilitate extraction. Critical extraction parameters, including pH, type and volume of extraction/disperser solvents, and centrifugation parameters, were systematically optimized using a Box-Behnken Design (BBD). This BBD approach enabled a comprehensive evaluation of the influence of these variables on extraction efficiency. Under optimal conditions, the method demonstrated excellent linearity within the range of 1.0-16.0 mg/L (R² = 0.9982). The limits of detection (LOD) and quantification (LOQ) were determined to be 0.326 mg/L and 0.987 mg/L, respectively, indicating good sensitivity. Comparative validation against a standard HPLC method, assessed using F-test and T-test, showed no statistically significant difference, thereby confirming the proposed method's accuracy and reliability. Overall, the proposed DLLME method offers a simple, efficient, environmentally friendly, and cost-effective approach for the accurate quantitative analysis of sodium diclofenac in pharmaceutical formulations.