Abstract:
Morphine is the most commonly used narcotic analgesic. It is found in the poppy
plant, opiates and metabolites of codeine. The complex metabolic pathways of heroin,
morphine and codeine complicate the interpretation of analysis of human samples.
This study compared the morphine-codeine ratios in whole blood from users of
heroin with that from medication with codeine as an index of heroin abuse.
Liquid-liquid extraction (LLE) was used to recover morphine and codeine in 1.0
ml of blood. Quantification was performed with a C18 reverse phase column (5 μm
100 Å 150 x 4.6 mm). The mobile phase consisted of 70 mM phosphate buffer pH 3
and acetonitrile (93:7, v:v). Detection was by uv-absorbance at 210 nm.
Retention times of morphine and codeine were 3.3 and 9.4 min, respectively.
The recovery for this method is more than 80%. Morphine to codeine ratios from
heroin overdose were 1.13-24.62 and 0.63-17.93 for the free and total forms,
respectively. For samples from codeine medication the free form of codeine could not
be detected.
When a urine sample is presumptively positive for morphine, measurement of
the morphine to codeine ratios in whole blood can be used to confirm whether the
morphine is a metabolite of codeine or heroin.