STABILITY OF MORPHINE-SULFATE IN SALINE UNDER SIMULATED PATIENT ADMINISTRATION CONDITIONS

Objective: To study the stability of morphine sulphate solutions under simulated administration conditions in a patient-controlled analgesic device. Method: Concentrations of 1 mg/ml and 10 mg/ml morphine sulph ate in saline were monitored over 16 days under slow continuous delive ry from Deltec Medication cassettes kept in the dark at a controlled t emperature of 32 degrees C and a humidity between 36 and 38%. The morp hine concentrations in the samples, collected at 0, 1, 2, 5, 6, 7, 9, 12, 14 and 16 days, were measured by a stability indicating high-perfo rmance liquid chromatographic method. Results: Throughout the study pe riod, the reservoir concentrations varied within 10% of their initial values and there was no chromatographic evidence of degradation. Howev er, the pH of both reservoirs decreased with time, but morphine is exp ected to be stable within the observed pH range. Conclusion: This stud y demonstrated that the concentrating effect due to evaporation under the storage conditions described, over 16 days, was not of significanc e and the product was stable.