Abstract

PHARMACOLOGICAL ROLE AND DIFFERENT ROUTES OF SYNTHESIS OF KETAMINE: A GENERAL ANESTHETIC – A MINI REVIEW

Santanu Giri, Amitesh Chakraborty and Tushar Adhikari*

ABSTRACT

Ketamine, called (RS)-2-(2-Chlorophenyl)-2-(methylamino) cyclohexanone is a widely used dissociative anaesthetic. It elicits its Pharmacological action mainly by inhibition of NMDA receptor. The enantiomeric 2S isomer is more potent than 2R isomer. At a dose below the anaesthetic dose, it acts as mild sedative and pain reliever. Intravenous dose shows 100% bioavailability, but oral route of drug administration shows bioavailability of only 16 – 20%. It is rapidly metabolized to norketamine (major metabolite) which is NMDA receptor antagonist causing anaesthesia and Hydroxynorketamine (minor metabolite) which is an antidepressant. Multiple synthetic routes of Ketamine are used. This review deals with different developed, patented or hypothesized synthetic routes of Ketamine. Both conventional routes and Green Chemistry routes has been encompassed here. Among the ten different routes discussed here, it has been found that the route of Eschweiler–Clarke reaction of Ketamine synthesis had multiple advantages. It recorded highest yield because of its simple reaction, shorter time, higher atom economy and less by-product and yield.

Keywords: Ketamine; Chemical synthesis; Esketamine; N-Methylaspartate; Anesthetics.