THE STUDY OF TRICYCLIC ANTIDEPRESSANTS IN FORMALIN-FIXED HUMAN LIVER AND FORMALIN SOLUTIONS

The stability of amitriptyline, nortriptyline, desipramine and imipram ine in formalin-fixed human liver tissue and formalin solutions was in vestigated. The levels of the tricyclic and its primary demethylated m etabolite in the frozen liver were determined and compared with levels obtained in the formalin-fixed liver and formalin solutions in which the liver was stored. It was obvious that some methylation of the seco ndary amine, nortriptyline, to the corresponding tertiary amine, amitr iptyline, and of desipramine to imipramine took place in the formalin environment. Nortriptyline was not detected in most cases, suggesting that it may degrade more rapidly than desipramine. There was no consis tent ratio between the concentration of the drug in the frozen fiver t issue versus formalin-preserved tissue or versus formalin solution. Th e methylation rates of the secondary amines could not be quantitated. Storage of the liver tissue in formalin at room temperature resulted i n leaching of the drugs into the formalin solution. The drugs tested m ay be detected for up to 22 months in the formalin-fixed liver and in the formalin medium.