Drug deposition in adipose tissue and skin: evidence for an alternative source of positive sweat patch tests

In a series of licit and illicit drug-related deaths, qualitative and quantitative analyses on extracts of adipose tissue and skin were performed by GC/MS. In all cases, the adipose tissue was found to contain drugs at concentrations lower than, approximately equal to, or even greater than the concentrations of the same analytes found in the blood, which may reflect a consequence of long-term chronic exposure, or acute intoxication, or some combination of both. Approximately one cubic inch of skin with adipose tissue was removed from the mid to lower abdominal region adjacent to the midline incision during autopsy. The drugs were recovered from the specimens following incubation and alkaline, acidic, and alkaline chloroform back extraction of one to three grams of tissue. Deuterated analogs of the analytes were added to the matrix at the beginning of the incubation period. Cocaine and free morphine (from heroin) were readily identified in several cases. The presence of these illicit drugs in adipose tissue raises significant forensic questions, especially the use of 'sweat patches' to monitor recent cocaine or heroin use in chronic drug users.