Effects Of Ethanol On The Toxicokinetics Of Ketamine In Rabbits

Objective 1. To develop a qualitative and quantitative method for the simultaneous determination of ketamine and its main active metabolite norketamine in serum and urine by GC and GC/MS. 2. To compare the toxicokinetic profiles of ketamine alone with coadministration of ethanol in serum and urine. 3. To observe the changes of vital signs of rabbits during the whole procedure after administrated.Methods 1. Gas Chromatography/Gas Chromatography-Mass Spectrometry (GC/MS): After adding SKF_525A (Internal Standard, IS), serum and urine samples were alkalized and extracted with ethyl acetate. Analysis was performed with a GC equipped with a NPD and a GC-MS. Qualitative analysis was based on retention time in the chromatographic system coupled with the ion fragmentation spectrum in the mass spectrometer. Quantitative analysis was based on an internal standard method. 2. Toxicokinetic study: ketamine-HCl of 0.15g·kg^-1 was administered orally to the rabbits of the ketamine-treated group. Ethanol of 3.0g·kg^-1 and ketamine-HCl of 0.15g·kg^-1 were administered orally to those of the ethanol- coadministration group. The serum and urine samples were collected before administration and at different time points after drug administration. The concentrations of ketamine and norketamine were determined by GC. Compartment model and toxicokinetic parameters were assessed by WinNorLin program. 3. Record of vital signs: Changes of important vital signs, such as electrocardiogram, blood pressure and respiration rate , etc. were recorded during the entire experiment by BL-5 biological functional experiment system.Results 1. The linear range for ketamine and norketamine in serum and urine by GC/MS was 0.2～40μg·mL^-1 and 5～400μg·mL^-1, respectively. The limit of detection was 0.05μg·mL^-1. The overall extraction recoveries of the analytes in serum and urine were more than 75% ; The analytical recovery was 96.31%～107.94%; The inter- and intra-day relative standard deviations of precisions were less than 10.0 %. 2. The mean serum concentration-time profile of ketamine after oral administration to rabbits was fitted to a two-compartment open model with first order kinetics and not affected by in combination with ethanol. For the model of ketamine, K₁₀,AUC, βand T_max in combination with ethanol changed increasely to those of ketamine administered alone .But T_1/(2K10),T_1/2β, A and C_max changed decreasingly to those of ketamine administered alone There was significant difference between two groups. For the model of norketamine, K₀₁ A, B and C_max changed increasingly to those of ketamine administered alone .ButT₍1/(2K01) and T_max changed decreasingly to those of ketamine administered alone There was significant...