The quantitative conversion of morphine 3-beta-D glucuronide to morphine using beta-glucuronidase obtained from Patella vulgata as compared to acid hydrolysis.

Methods to confirm morphine in urine require hydrolysis to liberate morphine from its 3-beta-D glucuronide (M-3G) conjugate. Lengthy enzyme hydrolysis procedures prolong testing turnaround time whereas rapid enzyme methods may produce a low conversion of M-3G to morphine. The purpose of this study was to evaluate the quantitative conversion of M-3G to morphine in human urine using a thermally stable beta-glucuronidase isolated from Patella vulgata; to compare these findings with those obtained from acid hydrolysis; and to compare between-run imprecision for both hydrolysis methods. We found both enzyme and acid hydrolysis techniques to be efficient, giving 90.4% and 92.8% conversion of M-3G to morphine, respectively. Also, both methods were found to be reproducible. Over a 14 week period, 20 opiate confirmation batches were analyzed by each hydrolysis method; the coefficient of variation for morphine liberated from M-3G was 5.5% for enzyme hydrolysis and 2.7% for acid hydrolysis.