HPLC-fluorescence detection for assay of tramadol binary mixtures with ibuprofen or chlorzoxazone in tablets and plasma: Analytical Eco-Scale and GAPI tools for green assessment

Abstract

Abstract Tramadol, a strong pain killer known for its addictive problems is either co-administrated or co-formulated with other analgesics or muscle relaxants. The power of fluorescence detection in HPLC is tested to resolve such mixtures in plasma matrix to reach the required sensitivity with simple sample treatment using just protein precipitation. The aim of this work was to develop an eco-friendly and sensitive HPLC method with fluorimetric detection for analysis of Tramadol in its two binary mixtures with Ibuprofen (mixture 1) and Chlorzoxazone (mixture 2) in two combined dosage forms and spiked plasma. Separation was done using a C18 column with mobile phase of acetonitrile and water (pH 3.5) in gradient elution and 1 mL/min flow rate. Detection was carried out with λ excitation/λ emission of 220 and 307 nm, respectively. The method was applied to detect the two binary mixtures in real plasma samples after invivo application to rats, to assure that the drugs’ metabolites do not affect the sensitivity or selectivity of the assay. Evaluation of greenness of the proposed method was done using semi-quantitative Eco‐Scale and new Green Analytical Procedure Index which showed that this method can be a greener alternative with higher sensitivity for analysis of both mixtures. The method (15 min-assay) was linear over concentrations of 0.1–10 μg/mL and 0.1–33 μg/mL in plasma. In addition, the proposed method was validated per ICH as well as FDA bioanalytical methods’ validation guidelines.