Capillary Electrophoresis Methods for the Determination of Tramadol: A Review

Tramadol is a widely used opioid analgesic frequently prescribed for treatment of moderate to severe, acute and chronic pain. It has a complex mechanism of action, acting both as a central opiate agonist and as a norepinephrine and serotonin reuptake inhibitor. It is a chiral substance, having two chiral centers in its structure and it is used in therapy as a racemic mixture of two of its enantiomers, (S,S)-tramadol and (R,R)-tramadol. In the last 25 years, several analytical procedures have been published in the literature for the achiral and chiral determination of tramadol from pharmaceutical formulations and biological matrices. Among these methods, capillary electrophoresis techniques have proved to be an efficient, reliable and cost-effective solution. The purpose of the present review is to provide a systematic survey to present and discuss the electrodriven methods available in the literature for the achiral and chiral analysis of tramadol.