Development of a method for analysis of ketamine and norketamine enantiomers in equine brain and cerebrospinal fluid by capillary electrophoresis.

This research focused on developing a procedure to analyze and measure the distributions of Ketamine and Norketamine compounds in horse brain and spinal fluid, using an adapted version of a previously established capillary electrophoresis based assay. The study found that these compounds enter the brain tissue and spinal fluid more readily than Norketamine metabolites.

Analysis Method of Ketamine and Norketamine Enantiomers

• Researchers adapted a previously developed enantioselective capillary electrophoresis (CE) assay, suitable for equine plasma, for the analysis of Ketamine and Norketamine in horse brain.
• An acidic pre-extraction method was used to eliminate interferences before the alkaline pH liquid/liquid extraction.
• The method allowed assay conditions for each enantiomer with limits of quantification (LOQs).’

Study Design and Sample Collection

• The study made use of samples from anesthetized horses as well as hose that were euthanized using an overdose of pentobarbital.
• The obtained samples included brain tissue, cerebrospinal fluid (CSF) and plasma.
• The method was therefore designed to be applicable to CSF much in the same way it applies to plasma.

Observations and Findings

• Results indicated that Ketamine and Norketamine enantiomers penetrate into the brain and CSF, but the transport of Ketamine enantiomers was found to be more favored than Norketamine.
• On the other hand, metabolites of Norketamine faced hindrance.
• These findings suggest that there may be stereoselective processes involved in the metabolism of Ketamine, as well as the transport of these metabolites from the blood into the brain tissue and CSF.

Future Research

• The researchers argue that more studies are needed to better understand the potential stereoselectivities of Ketamine’s metabolism and the transport of its metabolites from blood into brain tissue and CSF.