The stability of tetramine, morphine and meperidine in formalin solution

The stability of tetramine, morphine and meperidine in formalin solution is an important factor for drug analysis in forensic investigation. In this paper, the tissues (liver, kidney, lung and heart) from poisoned rabbits were immersed in 50 ml 10% formalin solutions for 4 months before examination. We compared the levels of tetramine, morphine, meperidine and the main metabolite normeperidine, measured by GC/NPD or GC-MS, in frozen rabbit tissues, formalin-fixed rabbit tissues, and formalin solution. There was a decrease in the levels of tetramine, morphine, meperidine in formalin-preserved tissues compared with the levels of these drugs in the frozen tissues. It is suggested that the formalin-fixed tissues and formalin solution should be analyzed at the same time to assure the accurate results.