ABSTRACT
BACKGROUND: Directly percutaneous injection of protein-denaturant hydrochloric acid (PDHA) into tumors can lead to fast killing of tumor, sustained drug release and prevention of in situ recurrence of tumor. However, whether implants can be used combined with denaturant still remains unknown. OBJECTIVE: To investigate the compatibility of fluorouracil implants and PDHA (6 mol/L). DESIGN, TIME AND SETTING: Observational study was performed in the Hefei Industry University between October 2006 and March 2007. MATERIALS: A total of 78 Wistar rats, weighing (200i20) g, half males and half females, were used for testing drug release in vivo. Drugs fluorouracil implants (H20030345; columniform particle, diameter 0.8 mm, length 4 mm; specifications: Fluorouracil 2 mg/particle; batch number: 20060922; meeting the National Drug Quality Standards [WS1-(X-103)-2005Z]) were provided by Wuhu Zhongren Pharmaceutical Company,Ltd. Hydrochloric acid (37%) was analytical reagent. METHODS: 96 tubes of the implants and PDHA were kept at (37.0± 0.5) ℃. Each time, six samples were collected at 1, 8, 16, 24, 96, 120, 168, 240, 360, 432, 480, 528, 600, 720, and 960 hours after incubation. Appearance of the implants was observed by microscope. Stability of fluorouracil in PDHA was determined by HPLC and ultraviolet absorb method. Based on the entering quantity and residual quantity of fluorouracil, the release rates were calculated. MAIN OUTCOME MEASURES: The approximate solubility, stability and morphological change of fluorouracil in denaturant and the corresponding drug release character in both denaturant and rats in vivo. RESULTS: At (37.0±0,5) ℃, the fluorouracil was stable for 960 hours in PDHA, the saturated concentration of fluorouracil was (22.72±0.04) g/L. The appearance of implants was intact. The surface was porous. Compared with the speed of releasing drug in rats, the speed of releasing drug was faster in the early stage of release process and slower in the later stage. The drug release was incomplete. At 1, 24, 96, 360 and 960 hours, the implants' release rates were (11.9±6.7)%, (37.9±5.3)%, (52.6±4.5)%, (75.3±3.8)%, and (85.5±2.1)%, respectively. CONCLUSION: The fluorouracil implants and hydrochloric acid (6 mol/L) are compatible and no influence is detected during the observation.