The Postmortem Diffusion Of Ketamine In Rabbits

ObjectiveThe aim of this study is to investigate postmortem diffusion of ketamine in acute poisoned rabbits and the mechanism of postmortem redistribution of ketamine in animals. The research results could provide a reference basis for sampling and analysis results evaluation in ketamine poisoning cases. It could also provide an evidence to identify ketamine delivery before or after the death.Methods1. The analysis method of ketamine:The samples of body fluids and tissues were alkalified and extracted by diethyl ether after adding SKF525A(internal standard). The extracts were qualitative analyzed by GC/MS and quantitative analyzed by GC-NPD with internal standard and working curve methods.2. The postmortem redistribution of ketamine in rabbits after being i.g. administration of ketamine and remove stomach:The rabbits in experimental group were given i.g. administration of ketamine with a dose of150mg·kg-1. The rabbits were executed by hypoxia method and removed stomach after2hours. The rabbits body were preserved at room temperatures (19℃-24℃) in the supine position. Cardiac muscle, liver, spleen, lungs, kidney, brain, upper limb muscles, cardiac blood, peripheral blood, urine, bile and vitreous humor of rabbits were taken out to detect ketamine at different times after death (Oh,3h,6h,12h,24h,48h,72h,96h). Rabbits in control group were given i.g. administration of physiologic saline. The body fluid and tissues were taken out correspondingly as blank check.3. The postmortem diffusion of ketamine in rabbits:The rabbits in experimental group were executed by hypoxia method, then given i.g. administration of ketamine with a dose of150mg·kg-1. The rabbits body were preserved at room temperatures (19℃-24℃) in the supine position. Cardiac muscle, liver, spleen, lungs, kidney, brain, upper limb muscles, cardiac blood, peripheral blood, urine, bile and vitreous humor of rabbits were taken out to detect ketamine at different times (3h,6h,12h,24h,48h,72h,96h). Rabbits in control group were given i.g. administration of physiologic saline. Body fluid and tissues of rabbits were taken out correspondingly as blank check. Results1. The rabbits executed by hypoxia method after being given i.g. administration of ketamine with a dose of150mg·kg-1for2hours later. The ketamine content in rabbits was as follow:urine> kidney> brain> liver, lungs> cardiac muscle, spleen> upper limb muscles> bile> cardiac blood, peripheral blood> vitreous humor (P<0.05). The concentration of ketamine in cardiac muscle, liver, lungs, upper limb muscles, urine, cardiac blood and bile of rabbits which were removed stomach after being given i.g. administration of ketamine had no significant difference from0h to96h(P>0.05).2. The rabbits which were executed by hypoxia method then being given i.g. administration of ketamine with a dose of150mg·kg-1preserved in the supine position. Ketamine in brain, vitreous humor, urine, upper limb muscles of the rabbits could not be detected from3h to96h after rabbits body being preserved. While ketamine in cardiac muscle and blood of rabbits body could be detected at24h after rabbits body being preserved, the change of ketamine content in cardiac muscle and blood of rabbits had no significant difference from24h to96h (P>0.05). The ketamine concentration in cardiac blood was higher than that in peripheral blood, the ratio of cardiac to peripheral blood concentration (C/P) was1.73(1.48-2.03). The ketamine in spleen, lungs and liver of rabbits body could be detected at48h after rabbits body being preserved, ketamine content in spleen, lungs and liver of rabbits body increased with time (P<0.05). The content of ketamine in lungs and liver was correlated with the distance to stomach. The nearer is, the faster it spreads, and the higher content it is, and vice versa.ConclusionThe organs which has rich blood supply, such as cardiac muscle, liver, lungs and spleen, have less effects on postmortem redistribution of ketamine when exclusive the effects of high concentration of ketamine in stomach on postmortem redistribution of ketamine in animals.Ketamine has postmortem diffusion in rabbits. Ketamine in stomach plays an important role in postmortem redistribution because of its postmortem diffusion with concentration gradient to the other neighboring tissues or organs. The change of ketamine content in tissues depends on the distance between tissues and stomach. Ketamine in brain, vitreous humor, urine, upper limb muscles of the rabbits body cannot be detected during96h after postmortem i.g. administration of ketamine to rabbits. The study results can provide an evidence to identify drug delivery before or after the death.