[Distribution of methadone in blood, cerebrospinal fluid, urine and organ tissues]

This study investigated the deposition of methadone in blood, liquor, urine and organ tissues, obtained from sheep after daily administration of methadone during 23 days. One sheep was killed two hours after methadone application, one sheep after 24 hours without methadone, and one sheep after seven days without methadone. The methadone determination was performed by radioimmunoassay. The concentrations measured represent the sum of methadone and its metabolites expressed in methadone equivalent/ml or g, respectively. The highest methadone levels were found in blood and liquor in the first 30 minutes. After seven days without methadone in blood, liquor and urine was methadone not more found. Only in the synovial fluid and vitreous humor measurable methadone levels were present.