Forensic drug testing for opiates. VII. Urinary excretion profile of intranasal (snorted) heroin.

The urinary excretion profile of free and conjugated morphine and 6-acetylmorphine was determined by gas chromatography-mass spectrometry (GC-MS) and immunoassay for six healthy male subjects after intranasal administration of 6 and 12 mg of heroin HCI. Results were compared with heroin administration (6 mg) by the intramuscular route. Heroin metabolites were rapidly excreted with peak concentrations appearing in the first or second specimen collection after drug administration. Concentrations of total morphine and 6-acetylmorphine after intranasal heroin were similar to those after intramuscular administration, but free morphine concentrations after the lower intranasal dose were significantly lower than the same dose given intramuscularly. Detection times for total morphine by GC-MS and immunoassay (300-ng/mL cutoff concentration) were generally 24-36 h, but were reduced to less than 12 h at the higher cutoff concentration of 2000 ng/mL. 6-Acetylmorphine concentrations were highly variable and short-lived; detection times (10 ng/mL) were approximately 2-3 h for most subjects, but some failed to produce positive specimens. Of 14 specimens with 6-acetylmorphine concentrations of 10 ng/mL or more, ten were associated with total morphine concentrations greater than 2000 ng/mL, and four specimens had total morphine concentrations less than 2000 ng/mL. Overall, intranasal administration of heroin produced a similar profile of excretion of heroin metabolites to intramuscular administration.