Chemical stability of hydromorphone hydrochloride in patient-controlled analgesia injector

Abstract

The chemical stability of hydromorphone hydrochloride in patient-controlled analgesia injectors was studied for 34 weeks at different temperatures. The sterility of the solution was also monitored at the end of 16-week storage. For the determination of stability of hydromorphone, five groups of six patient-controlled analgesia injectors containing hydromorphone solutions of 0.2 mg/mL (6 mg of drug solution in 30 mL 0.9% normal saline) sealed with plastic tip caps were stored at 5°C in refrigerator, 20°C on benchtop, 20°C in dark, 35°C in dark, and 50°C in dark. Chemical stability was determined throughout a storage period of 34 weeks using high performance liquid chromatography. Sterility test was also performed at 16 weeks. Hydromorphone solutions stored in different conditions up to 34 weeks remained clear and free of visible precipitation throughout the study. After 8 weeks of storage in the patient-controlled analgesia injectors in different temperature conditions, the concentrations of hydromorphone in all the samples remained >95% of their original value. At 16 and 34 weeks, the concentration of hydromorphone in the injectors decreased to 92% to 96% and 86% to 88% of their original value, respectively. In the sterility test of bacterial contamination of the hydromorphone solutions in the patient-controlled analgesia injectors at 16 weeks, none of the injector solutions showed evidence of microbial growth after 14 days of incubation in fluid thioglycolate medium. This study demonstrates the stability and sterility of hydromorphone hydrochloride solution.