Ketamine is considered a dissociative anesthetic drug. The drug also has anesthetic properties that have been used in both human and veterinary medicine [1]. Along with anesthetic benefits, there are certain reactions to ketamine that make it appealing to illicit users [2].

In social situations ketamine is often used intranasally and orally and it can be injected, the rapid onset of effects from oral or nasal use makes it more convenient [1]. There are two isomers of ketamine: S(+) ketamine and R(-) ketamine. Ketamine metabolism is mediated by hepatic microsomal enzymes. Ketamine causes increased intracranial pressure, bronchodilation and stimulation of cardiovascular system. It is used for premedication, sedation, induction and maintenance of general anesthesia. Ketamine is an ideal anesthetic agent for trauma victims, patients with hypovolemic and septic shock, patients with pulmonary diseases [3]. Ketamine and its metabolites in biological samples (blood, urine, hair, and so on specimens) are determined and detected by different methods include GC, GC/MS, HPLC, etc [4].

Later on, it was being used by recreational users. The increase in illicit use prompted ketamine’s placement in schedule III of the United States controlled Substance act in August 1999 [5]. A new color test for the identification of ketamine is reported by treating ketamine with alkaline bromide produces a deep purple color [6]. There are very little studies on its electrochemistry except few. Ion-selective membrane electrode to the drug ketamine hydrochloride has been constructed using a modified PVC membrane which has ionic end-groups as ion-exchanger sites and which was cast using plasticized with ortho-nitrophenyloctyl ether (o-NPOE) as plastisizer. This drug electrode shows excellent Nernstian responses (59 mV per decade) in the concentration range 1×10^-5–1×10^-2 M with a detection limit of 5×10⁻⁶ M. Response time was about 10 s for ketamine concentrations between 1×10⁻⁵ and 1×10⁻² M. The response is not affected by pH between 4.0 and 8.5. Selectivity coefficients against various organic and inorganic cations were evaluated. The electrode was applied for determination of ketamine hydrochloride in pharmaceutical preparations using direct potentiometry. The drug electrode has also been used to study the interaction of bovine serum albumin with ketamine in buffer solution (phosphate, pH 7). The saturated quantities of ketamine binding were 114, 32 and 25 mol/mol in 0.01, 0.02 and 0.1% of protein, respectively. The Hill equations were applied to obtain co-operative drug bindings to bovine serum albumin at 27 °C [7].

The kinetics of methylamine oxidation at a gold electrode in contact with an alkaline electrolyte solution was studied. The adsorptive behavior of substrate molecules was determined by changes in the potential range of gold oxide layer formation. The general reaction pathways of methylamine oxidation on the gold electrode are proposed [8]. A series of alcohols and amines have been oxidized at oxide-covered nickel, silver, copper, and cobalt anodes in aqueous alkaline solutions. The kinetics of these electrode processes have been studied and it is shown that the mechanism of these oxidations involves hydrogen abstraction from the substrate by an oxide species rather than direct electron transfer to the anode. The mechanism put forward is compared with those commonly suggested for the chemical reactions of transition-metal oxides and for heterogeneous catalysis [9]. A liquid chromatography/atmospheric pressure ionization mass spectrometry has been developed for the determination of ketamine, norketamine, and dehydronorketamine in human urine. A separation of these analytes in urine samples without tedious pretreatment procedures has been achieved within 10 minutes linear calibration curves of these analytes with coefficients better than 0.998 have been obtained over a wide range from 12.5 to 200 ng/mL. The accuracy was between 2.1% and 7.2% with detection limits at levels of 0.02 ng/mL, 0.02 ng/mL and 0.93 ng/mL for ketamine, norketamine and dehydronorketamine, respectively. The results demonstrate the suitability of the liquid chromatography/atmospheric pressure ionization mass spectrometry approach to analyze trace ketamine, norketamine and dehydronorketamine in urine. Urinary ketamine and norketamine levels were relatively low at 4-24 hours intervals and were difficult to assay in a normal laboratory. In the present study, the determination of urinary dehydronorketamine levels at 2-24 hours appears to have a great potential for use in Schedule III controlled drugs management [10].