STABILITY OF TRIHEXYPHENIDYL IN STORED-BLOOD AND URINE SPECIMENS

Trihexyphenidyl (THP) is an anticholinergic agent with forensic toxico logical interest. The stability of THP was studied in postmortem blood and urine samples at a concentration of 0.25 mu g/ml under different storage temperatures. After solid phase extraction (SFE), THP was meas ured by gas chromatography. On day zero and at intervals over a 6 mont hs period, there was no significant loss of THP at the storage tempera tures -20 degrees C and 4 degrees C in the spiked and authentic sample s. Blood and urine samples stored at 25 degrees C showed a maximum rec overy loss (about 14%) of THP after 3 months of storage. This loss was considered a significant change and corresponded to a P value < 0.046 . The study demonstrates that the analysis of blood and urine samples containing THP would produce consistent results when they are stored f or 6 months at -20 or 4 degrees C and for 3 months at 25 degrees C.