engleski

LONG TERM STABILITY OF METHADONE AND EDDP IN CLINICAL BLOOD SAMPLES

Methadone is a synthetic opiate, widely used to help heroin addicts undergoing maintenance programs. Determination of methadone and its metabolites represents a routine procedure in forensic toxicology. Biological samples, according to legislation, should be stored at least six months after the first analysis. Storage conditions, combined with the stability of drugs, can significantly affect the interpretation of results. Due to these reasons, it was necessary to examine the time effect on the stability of methadone and its metabolite 2-ethylidene-1, 5-dimethyl-3, 3-diphenylpyrrolidine (EDDP) in biological blood samples stored for more than six months. The effect of long-term stability of methadone and EDDP was studied by a repeated quantitative analysis of the same samples after long-term storage at -20 °C. A total of 50 clinical blood samples were analysed, and 20 samples, in which the presence of methadone and EDDP was confirmed, were reanalyzed after long-term storage period. The first analysis was performed 1-3 days after sampling, and the repeated analysis was performed after 293-369 days of storage for each sample. GC/MS analysis of clinical blood samples preceded the LLE sample preparation, and results were compared. In the repeated analysis, all blood samples showed lower methadone concentrations (from 2.04% to 80.74%). Contrary to expectations, reanalysis of all blood samples showed absence of EDDP. Further experiments on methadone and EDDP stability in stored biological samples, at different storage conditions and in combination with other factors, should be undertaken to ensure the proper interpretation, reliability and reproducibility of the analysis results.

methadone, EDDP, blood samples, stability, GC/MS, toxicology

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