The in vitro instability of heroin in blood or plasma has been well-documented. Nakamura et al. studied the rate of degradation and production of breakdown products in serum, fresh blood, and postmortem, heparinized whole blood buffered to pH 7.4 and incubated at 37.5 °C. The half-life of heroin degradation was less than 30 min in all specimen types. The major breakdown product was 6-acetylmorphine.
Barrett et al. found similar results at this temperature in plasma, but found longer half-lives of 354 and 18 minutes at 4 °C and 25 °C, respectively. Breakdown to 6-acetylmorphine but not morphine, was observed. Moriya and Hashimoto found that 6-acetylmorphine was stable in urine over a loudly period at temperatures ranging from 4 °C to 37 °C. The stability of morphine in whole blood was studied by Al-Hadidi and Oliver. Morphine was added to blood that was then stored at room temperature, refrigerated, or frozen.
Aliquots of blood at each temperature were removed at 2, 4, 6, and 8 weeks and 3, 6, 9, and 12 months. Under all conditions and times tested, more than 80% of the morphine initially present was measured. Moriya and Hashimoto found that morphine was stable in postmortem blood, liver, and urine specimens over a 10 day period at temperatures ranging from 4 °C to 37 °C. The stability of morphine-3-glucuronide SMOG was examined by several researchers.
Moriya and Hashimoro found that M3G was not converted to free morphine in blood and urine specimens stored from 4 °C to 37 °C over a 10-day period. M3G was hydrolyzed completely to free morphine in liver specimens stored at 18 °C and 37 °C over 10 days, but was stable at 4 °C over the same time period. Carroll et al. found that at 5 °C M3G was stable for 30 days in unpreserved or fluoride-preserved postmortem blood at pH 6.5 and pH 7.4. M3G was also stable in sterile urine after 240 days at 5 °C at pH 6.0 and pH 8.0.