| Objective:1. To establish the simultaneous determination of 5 common local anesthetics in samples.2. To establish a tetracaine poisoning death, study the distribution of tetracaine in poisoned rat and concentration ratio in liver and blood. To get order concentration of tissues and body fluid and important data of toxicology.3. Compare the distribution character of tetracaine in organs and body fluids of rat model and provide science evidences for test materials collections, determinations, analysis, distinguish of death reason and forenic determination for cases of tetracaine poisoning.Methods:1. Qualitative analysisAfter adding lidocaine(internal standard), body fluids and tissues were acidified and extracted by diethyl ether. Qualitative analysis was based on retention time in the chromatographic system.2. Quantitative analysisStandard series of tetracaine and internal standard lidocaine were made up and all were determined by gas chromatography. Calibration regression were done while concentration of tetracaine as X and peak areas ratio of tetracaine to lidocaine as Y. The regression equation was Y=a+bX which was the base of quantitative analysis for concentration of tetracaine in samples.3. Model set up24 SD rats (female) were randomly divided into two experimental groups (each group 6 rats) and two parallel group (each group 6 rats). Experimental group one were given intravenous administration of tetracaine at dose 4 times of 10.39mg/kg, which was LD50 of rats, experimental group two were given sublingual administration of tetracaine at the same dose. And parallel group one were given intravenous administration of physiological saline, parallel group two were given sublingual administration of glucose. Rats in experimental group one died in 30 min and dissected after death as soon as possible. Rats in experimental group two twitch in ten min and executed by aeroembolism after 30 min. Brain, lungs, liver, kidney, blood, urine and cardiac blood were collected and kept at -20℃.Samples were extracted and determine as mentioned above.Results1. Determination results: The peak of 5 common local anesthetics is successively lidocaine, procaine, ropivacaine, tetracaine and bupivacaine. The linear range of tetracaine in blood and liver are 5.0～500.0μg/mL and 5.0～500.0μg/g. The limit of detection in blood and liver are 0.5μg/mL and 0.5μg/g(S/N≥3). The extraction recoveries are 101.7±4.1%, 99.6±5.4%, and 101.3±2.0%. The inter-day and intra-day relative standard deviation of precision are less than 5.2% and 2.7%.2. Symptoms: The rats in experimental group one showed the convulsion, respiratory depression after given intravenous administration of tetracaine within 1～5min, and died in 30 min. Rats in experimental group two showed the convulsion, excited and disturbed. Breathing decrescendo and frequency increase as time goes by. Returned to normal after 20 minutes.3. Distributions: Concentration of tetracaine in body fluids and organs of experimental group one were: cardiac blood>liver>stomach>lungs≈spleen>cardiac muscle>brain≈kidney. Concentration of tetracaine in body fluids and organs of experimental group two were: spleen>kidney>lungs>liver>cardiac muscle>cardiac blood>brain>stomach.Conclusion1. The analytical method could determine 5 common local anesthetics simultaneously. This method is high convenience and speed, efficiency and precise. It is suitable for forensic toxicological.2. The study has established the two distribution models. The data showed that concentrations of tetracaine in liver and blood were high in experimental group one, and concentrations of tetracaine in spleen and kidney were high in experimental group two.3. To cases caused by tetracaine poisoning, different ways leading to death will lead to different distribution. Compare the distribution character of tetracaine in organs and body fluids of rat model and provide science evidences for test materials collections, determinations, analysis, distinguish of death reason and forenic determination for cases of tetracaine poisoning. |
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