Development of new formulation and its evaluation by capillary electrophoresis of tablets containing tramadol hydrochloride and paracetamol.

A quick and efficient method to eliminate pain is combining complementary action and substances with synergic effect. Such an association is the one between tramadol hydrochloride and paracetamol, in which the rapid reaction time of the paracetamol is combined with the long-term effect of the tramadol hydrochloride. Our aim was to develop and characterize alternative tablet formulations containing tramadol hydrochloride 37.5 mg and paracetamol 325 mg with different excipients in different ratio, and also the development of a new electrophoretic method for the quantitative determination of the active substances. The tablets were evaluated for physical characteristics (weight, thickness, diameter, mechanical strength, friability, disintegration time), drug content and dissolution following Ph.Eur.7 and USP 35 guidelines. A new capillary electrophoretic method was developed for the determination of the two active substances. Capillary electrophoresis proved to be an efficient method for the determination of drug content and also for the dissolution profile. The two substances were separated based on the differences between their own electrophoretic mobilities, and determined in UV at two different wavelengths. Tablet formulation proved to be a significant factor in quality of tramadol hydrochloride/paracetamol tablets, as considerable differences between tablets containing different excipients were found; while capillary electrophoresis can be considered a useful alternative for the quantitative determination of tramadol hydrochloride/paracetamol combinations.