Distribution and stability of paracetamol in postmortem rat serum and tissues

Paracetamol is a common analgesic and antipyretic over the counter agent that frequently causes accidental and suicidal deaths. In legal cases, it is mandatory to show the acute poisoning in proper biological samples and to keep these samples which are analyzed toxicologically for the time defined by law in many countries as well as in Turkey. During this time, the amount of substance in the sample may be changed due to various reasons (storing conditions, not to use preservatives for storing purposes etc.)We aimed to investigate the stability of paracetamol in different storing conditions such as, serum samples stayed at +40C and -200C, whilst liver samples at -200C. We used solid phase extraction and GC/MS in samples of the paracetamol intoxicated Wistar Albino rats. We tried to show the distribution in postmortem serum, liver, kidney and brain tissues.42 Wistar Albino rats were intoxicated acutely by paracetamol, using the gavage method. The serum samples were stored for 30 days and evaluated for stability of paracetamol. We measured the values of paracetamol from the beginning of the experiment and repeated to measure it by the days one, two, three, ten, fourteen, twenty one and thirty. We observed that serum paracetamol concentrations had changed daily. We had observed statistical differences in various days (p<0.001).The values of various measurements are compared and we had noticed a significant difference (p=0.05) on the thirtieth experimental day. We had obtained that paracetamol serum levels were changing for the thirtieth day in various ratios, 66.30% and 33.78%, depending on the storing conditions respectively ?+4oC? and -20oC. The stability of paracetamol in liver stored at -20oC was also evaluated for 30 days. We also observed that the paracetamol concentration levels were changed as 30.26% on the first day and as 94.97% on the thirtieth day in the liver sample extractions. The distribution of paracetamol levels measured in various organs were as 2.68 mg/g, 1.11 mg/g, and 0.68 mg/g in liver, kidney and brain samples respectively.We had concluded that the amount of paracetamol in serum or liver samples in acute paracetamol poisonings did not show any meaningful differences during thirty days of storage in comparison to the starting values. Further studies can be of valuable and various studies should be performed in understanding the exact storage period of liver and serum samples in intoxication cases.