To develop the chitosan /polyethylene glycols succinate (CH/PEG-SA) mitomycin C (MMC) film drug del ivery system and its release effect in vitro. Methods MMC loading in composite films was determined using a UV-visible spectrophotometer. Freeze-dried films (90 mg) were immersed in 1 mL PBS buffer (pH 7.4). The concentrations ofMMC releasing in vitro were calculated refer to the standard curve of relationship between the concentrations of MMC and the value of UV-visible spectrophotometer. The curve of the concentrations of MMC releasing from the films in vitro was drawn at different time. The relationship between the films, structure and the drug releasing was revealed. Results The films showed swell ing without brittleness. The equation of Linear Regression was y=0.593x3– 2.563x2 +25.944x – 0.236 (R2=1.000). The film had a good drug del ivery capabil ity. The samples weighing 20 mg were soaked into the l iquid of PBS, the releasing concentrations of MMC were 14.961 6 μg/mL at 12 days, 14.482 4 μg/mL at 18 days and 11.409 2 μg/mL at 32 days, which was higher than ID50 of MMC (10.471 3 μg/L) to fibroblast. Then MMC was released at a low concentration. The releasing concentrations of MMC was 0.179 3 μg/ mL at 60 days until being del ivered completely. Conclusion The flexibil ity is enhanced , and the mechanical function is improved, so that there is better nature of membrane. The initial burst is avoided more effectively, and the drug releasing would be maintained for a certain time.
To investigate the effects of basic fibroblast growth factor (bFGF) on necrosis rate, succinate dehydrogenase level and oxygen consumption of the skin flap, 18 Wistar rats were divided into 2 groups. Caudally based skin flap was raised on the back of each rat. Nine micrograms bFGF or normal saline with heparin was instilled under the flaps respectively after closure of the wounds. After 7 days, the necrosis rate of each wound was measured. The result showed that in bFGF group, the average necrosis rate of skin flap was 18.2%, less than that of the control group (37.14%). Succinate dehydrogenase content and oxygen consumption in bFGF group were higher than those of the corresponding sites in the control group (P lt; 0.05). It was suggested that the use of bFGF resulted in the decrease rate of necrosis of skin flap, and it maintained higher succinale dehydrogenase level and oxygen consumption. It was concluded that bFGF would probably be valuable for clinical use.