Determination of Ketamine in Human Brain and Liver Tissues

Ketamine hydrochloride is administered as an anaesthetic for human and veterinary use. Several methods have been suggested for the estimation of ketamine. Conventional method for determination of ketamine hydrochloride is non-aqueous titration. Other methods available in the literature are direct UV-visible spectrophotometry, gas chromatography-mass spectrometry and liquid chromatography. The work presents determination of ketamine and its metabolite, norketamine, from liver and brain tissues along with pyrovalerone, another drug used during administration of anaesthesia. The development and validation of the new method for determination of unchanged ketamine from tissues incorporated the use of the internal standard phenacetin. The new method is fast and sensitive, and also enabled the qualitative determination of other drugs present in the matrix along with ketamine. The extraction procedure involved the modification of Stas-Otto method and the ammonium sulphate method used for extraction of basic drugs in the laboratories.