The Pharmacokinetics of Morphine and Codeine in Human Plasma and Urine after Oral Administration of Qiangli Pipa Syrup.

Papaveris pericarpium, a natural source of morphine and codeine, is the principal active component in many antitussive traditional Chinese medicines. We herein report the first PK study of papaveris pericarpium in human plasma and urine following oral administration of single (15, 30, 60mL) and multiple dose (15mL) of Qiangli Pipa Syrup (MOR 0.1mg/mL, COD 0.028mg/mL) by monitoring morphine and codeine using a HPLC-MS/MS method. Their T-max and t(1/2) values are independent of dosages, while the AUC(0-t) linearly increased with higher dosages, indicating linear PK characteristics. AUC(0-t) increased obviously after multiple doses, indicating possible risk of accumulative toxicity. Urine studies suggested risks of positive opiate drug tests with a cutoff of 300ng/mL, which lasted 6-14h at different doses. These results provide important information for clinical safety, efficacy and rational drug use of Qiangli Pipa Syrup and also guide the related judicial expertise of its administration.