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Evaluation of analytical procedures for urinary codeine and morphine measurements
1Department of Clinical Pharmacology, Karolinska Hospital, Stockholm, Sweden.
Journal of Analytical Toxicology
|May 1, 1994
Summary
Accurate morphine and codeine quantitation in urine requires specific hydrolysis. Acid hydrolysis with hydrochloric acid (HCl) and heating proved most effective for analyzing drug conjugates in patient samples.
Area of Science:
- Clinical Chemistry
- Analytical Toxicology
- Pharmacology
Background:
- Accurate quantitation of morphine and codeine in urine is crucial for clinical and forensic toxicology.
- Urine samples contain free and conjugated forms (glucuronides) of these opioids, necessitating effective hydrolysis for total drug measurement.
- Various hydrolysis methods exist, but their efficiency and reliability for opioid analysis require careful evaluation.
Purpose of the Study:
- To evaluate and compare different analytical procedures for the total quantitation of morphine and codeine in urine.
- To determine the optimal hydrolysis conditions for maximizing the recovery of opioid conjugates.
- To validate a robust analytical method for application to authentic patient samples.
Main Methods:
- Comparison of urine hydrolysis using hydrochloric acid (HCl) and four different enzymes.
- Evaluation of hydrolysis conditions, including HCl concentration, bisulphite presence, temperature, and time.
- Quantitation of morphine and codeine using Flame Ionization Detection (FID) gas chromatography and Ion-Trap Gas Chromatography/Mass Spectrometry (IT-GC/MS).
Main Results:
- Complete hydrolysis of glucuronide conjugates required 6.5M HCl with bisulphite at 100°C for 20 minutes.
- This optimized acid hydrolysis procedure showed good agreement with direct liquid chromatography analysis of free and conjugated opioids.
- Enzymatic hydrolysis methods exhibited higher variability and were more time-consuming.
- Both FID GC and IT-GC/MS provided good quantitative agreement for opioid analysis.
Conclusions:
- Optimized acid hydrolysis using 6.5M HCl is the most efficient and reliable method for total morphine and codeine quantitation in urine.
- The validated analytical procedure, employing this hydrolysis method, is suitable for analyzing authentic patient samples.
- Enzymatic hydrolysis methods are less suitable due to time consumption and variability.