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The introduced research presents a novel in vivo quantitative method for assay of mixtures of pregabalin and tramadol as a common combinations approved for treatment of neuropathic pain. Green analytical chemistry is a recently emerging science concerned with control of the use of chemicals harmful to the environment in various analytical methods. Consequently, a green high‐performance thin layer chromatography (HPTLC) method was achieved for determination of the mixture in human plasma and urine satisfying both analytical and environmental standards. The separation was achieved on HPTLC sheets using a separating mixture of ethanol–ethyl acetate–acetone–ammonia solution (8:2:1:0.05, by volume) as a mobile phase. The sheets were dried in air then scanned at two wavelengths. For tramadol, 220 nm was chosen; however, pregabalin is an unconjugated drug, so its determination was a challenge. Hence for pregabalin, the plates were sprayed with ethanolic solution of ninhydrin (3%, w/v), to obtain a conjugated complex, which could be assessed at 550 nm. Furthermore, the developed method fulfilled the US Food and Drug Administration validation guidelines, and proved to be useful in therapeutic drug monitoring of this combination. The Eco‐scale assessment protocol was implemented to determine the greenness profile of the applied method. [ABSTRACT FROM AUTHOR]

Membrane-selective electrodes were used to determine benazepril hydrochloride (BZ) and trandolapril (TR) in their binary mixtures with hydrochlorothiazide (HZ) and verapamil (VR), respectively. This method involves construction of four water insoluble ion-association complexes: benazepril-tetraphenyl borate (BZ-TPB), benazepril-reineckate (BZ-R), trandolapril-tetraphenyl borate (TR-TPB), and trandolapril-reineckate (TR-R). These complexes were used as electroactive materials in polyvinyl chloride (PVC) matrix membrane sensors in order to determine the two aforementioned drugs in their pharmaceutical formulations and in plasma. The performance characteristics of these sensors, evaluated according to IUPAC recommendations, revealed a fast, stable, and linear response for BZ and TR. The suggested procedures were checked using laboratory-prepared mixtures and were successfully used to analyze their pharmaceutical preparations. The results obtained using the proposed method were statistically analyzed and compared with those obtained using previously reported methods. [ABSTRACT FROM AUTHOR]