| Objective1. To establish a postmortem distribution model and a postmortem diffusion model of propafenone(PPF) in rabbits; To establish a decomposition kinetics model of PPF in preserved specimens of dogs.2. To study the postmortem distribution and postmortem diffusion of PPF in rabbits and decomposition kinetics of PPF in preserved specimens of dogs, and to provide a scientific evidence for the forensic identification of PPF poisoning death.Methods1. Postmortem distribution. Six rabbits were given an intragastric administration (ig) of PPF with a dose of 8 LD50 (440mg/kg). As soon as the blood pressure, respiration and ECG disappeared, the rabbits were dissected, and the specimens such as bile, lung, liver, kidney, spleen, urine fluid, heart blood, heart, brain, vitreous fluid, muscles of right lower limb were sampled immediately, in which the concentration of PPF was determined qualitatively by a high-performance liquid chromatography (HPLC)2. Postmortem diffusion. After being executed by an aeroembolism for 1 h, fifteen rabbits were given a dose of 8 LD50 (440mg/kg) by ig and placed at room temperature(20℃). Three animals were randomly dissected after postmortem administration of PPF at 4h,8h,12h,18h,24h respectively and the specimen such as heart blood, bile, urine, vitreous fluid, muscle of right lower limb, chest muscle, heart, liver, spleen, lung, left and right kidney and brain were sampled and stored at-20℃in refrigerator for detection, in which the PPF was determined by a high-performance liquid chromatography.3. Decomposition kinetics of PPF in preserved specimen of dogs. After being given an intragastric administration of PPF with a dose of 4LD50 (800mg/kg) for 1h,6 dogs were executed, and the heart-blood and liver of every dog were sampled and divided into three parts and preserved at -20℃,-4℃,20℃respectively, in which PPF was determined by a high-performance liquid chromatography at 0h,24h,72h,5d,7d,30d,60d,120d,180d,240d and 300d after the preservation. The mean C-T data of PPF in preserved blood and liver was manipulated by WinNorLin's pharmacokinetics software. The kinetic model was decided by AIC information criterion. The decomposition kinetic equation and parameter were estimated and calculated. 4. Statistics Data was expressed as mean±SD model and analysed statistically with SPSS 11.5 software by One-Way ANNOVA t test.Results1. Postmortem distribution. The concentration of PPF detected in bile(109.59±66.25μg/mL) of poisoning death rabbits with a 8LD50 dose was highest, followed by lung (78.60±37.82μg/g), liver (47.11±53.90μg/g),kidney(20.57±12.78μg/g), spleen (20.09±15.02μg/g), urine fluid(20.05±18.85μg/mL), heart blood (12.99±15.87μg/mL),heart (7.47±10.63μg/g), brain(5.62±5.99μg/g),vitreous fluid(2.10±3.51μg/mL), muscles of right lower limb (1.96±1.61μg/g).2. Postmortem diffusion. Except for in brain and vitreous fluid at 4h, PPF was detected in all other specimens sampled at 4h,8h,12h,18h and 24h after the postmortem administration of PPF in rabbits. PPF detected in liver, spleen, left and right kidney, urine fluid, right lower limb ascend and reached a peak value at 12 h after the postmortem administration death, then descended constantly. The concentration of PPF in vitreous fluid, bile, lung, brain, heart, heart blood, chest muscle ascended and reached a peak value at 18 h after the postmortem administration. The concentration of PPF in bile, brain, heart showed a time dependent increase progressively within 24h after the postmortem administration, and PPF in vitreous fluid, lung, heart blood, chest muscle showed a time dependent decrease constantly in more than 18h. Compared with PPF detected in poisoning death rabbits at a 8LD50 dose, the highest concentration of PPF detected in all of the specimen at 4-8h and in bile, liver, lung, brain and urine fluid at 12-18h after the postmortem administration was lower (P<0.05);while the highest concentration of PPF in spleen, left kidney, heart, heart blood, muscle and vitreous fluid at 12-18h was higher (P<0.05).3. Decomposition kinetics. The concentrations detected in preserved blood and the liver descended significantly in 10 monthes. There was not a significant change in the PPF concentration in blood and liver stored for 5d (P>0.05). The concentration of PPF in the liver and blood stored at 20℃,4℃and -20℃decreased from 100% at 0h to 37.77±5.93%,38.63±8.65%, 42.81±20.27%(P<0.05) and 22.39±10.25%,19.87±7.73% and 34.11±8.18%(P<0.05) at 7d respectively. The decomposition kinetics of PPF in blood and liver met the tow compartment open model with a first order kinetics, and could be expressed by Ct=Co-αt+Cte-βt. The fast decomposition half-lifes (t1/2α) of PPF in livers of poisoned dogs, which were stored at 20℃,4℃and -20℃, were respectively 3.6d (α=0.1907),2.2d (α=0.3223) and 9.6d (α=0.9629), and the slow decomposition half-life (t1/2β) were respectively 186.6d (β=0.0037),172.5d (β=0.0040) and 287.5d (β=0.0024); The fast decomposition half-life (t1/2α) of PPF in blood of poisoned dogs, which were stored at 20℃,4℃and -20℃were respectively 2.5 d (α=0.2763),4.2d(α=0.1638) and 10.7 d(α=1.0228), and the slow decomposition half-life (t1/2β) were respectively 215.Id (β=0.0028),242.1d (β=0.0024) and 285.2d(β=0.0023). The predicted values of mean PPF concentration calculated by Ct=Co-αt+Cte-βt were close to the observed values.Conclusion1. The postmortem distribution, and postmortem diffusion model of PPF(8LD50,ig)in rabbits and the decomposition kinetics model of PPF(4LD50,ig) in preserved samples dogs have been developed, and A HPLC methods for the quantitative analysis of PPF in biological material has been established, which can be applied to forensic identification and forensic toxicokinetics of PPF poisoning death case.2. The order of PPF contents detected in poisoning death rabbits was bile, lung, liver, kidney, spleen, urine fluid, heart blood, heart, brain, vitreous fluid, muscles of right lower limb. It was suggested that besides blood, bile, lung and liver should be sampled as specimen for analysis in the forensic identification of PPF poisoning death case.3. There was a postmortem diffusion of PPF in rabbits. Only in the early time after the postmortem administration, PPF was not detected in brain and vitreous of rabbits. The highest concentration of PPF detected in spleen, left kidney, heart, heart blood, muscle and vitreous fluid in rabbits after the postmortem administration may be higher than in poisoning death rabbits with the same dose of 8LD50. It should be taken into consideration that the postmortem diffusion and postmortem redistribution can affect the analysis of PPF in the forensic identification of PPF poisoning death case.4. PPF in preserved blood and the liver could be decomposed. The content of PPF in samples stored for 5d was relatively stable. PPF in samples stored for more than 7d showed a time-dependant descend. Specimen's being stored at low temperature could make the decomposition of PPF slow down. It suggests that the specimen for analysis of PPF should be submitted within 7d in the forensic identification of PPF poisoning death case, otherwise, samples should be frozen, submitted and analysed as soon as possible.5. The decomposition kinetics of PPF in stored blood and the liver meets the tow compartment open model with a first order kinetics. In the forensic identification of PPF poisoning death, the equation as Ct=Co-αt+Cte-βt and decomposition kinetics parameter can be used to estimated the PPF concentration in the specimens at sampled time, and provide a scientific evidence for the forensic identification of PPF poisoning death case. |
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