Urinary Kinetics of Heroin Metabolites in Pigs Shortly After Intake

In previous experimental studies on heroin metabolites excretion in urine, the first sample was often collected a few hours after intake. In forensic cases, it is sometimes questioned if a positive urine result is expected e.g., 30 min after intake. The aim of this study was to investigate urinary excretion of heroin metabolites (morphine, 6-monoacetylmorphine (6-MAM) and morphine-3-glucuronide (M3G)) every 30 min until 330 min after injection of a 20 mg heroin dose in six pigs. Samples were analyzed using a previously published, fully validated liquid chromatography-tandem mass spectrometry method. All metabolites were detected after 30 min in all pigs. The time to maximum concentration (Tmax) median (range) for 6-MAM and morphine was 30 min (first sample) (30-120), and 90 min (30-330) for M3G. In four of the six pigs, the Tmax of 6-MAM and morphine was reached within 30 min. All analytes were still detectable at the end of study. This study showed that positive results in urine are expected to be seen shortly after use of heroin in pigs. Detection times were longer than previously indicated, especially for 6-MAM, but previous studies used lower doses. As the physiology of these animals resembles that of the humans, transferability to man is expected.