| Objective: To analyze the effect of PEGylation on the safety and effect (in vivo and in vitro) of TCS, and estimate the significance and importance of PEG-TCS. Methods: Sprague-Dawley rats aging 5～6 weeks, weighing between 85～105g were used in the long-term toxicity. 160 rats were randomly divided into 4 groups. Each group were injected different dose PEG-TCS or only solvent, first once weekly, once two weeks one month later. Drugs were stopped, some rats were sacrificed 180 days later, the residual were subjected to 30 days recovery test. Clinical symptoms were observed and laboratory tests were examined in all rats. Guinea pigs were sensitized with antigens on days 1, 3, 5, fourteen days after the third sensitizing injection, the guinea pigs were challenged by an intravenous injection into the hind limb peripheral vein with the same antigen to evoke systemic anaphylaxis, signs were observed for 30 minutes immediately after injection. Middle or early gestation mice were injected drugs, and sacrificed 48 or 120 hours later. Dead and live fetuses were noted and the abortifacient rate was calculated. Rats were intradermal injected antiserum in back, antigens were intravenous injected through tail vein with Evens blue, then the seepage of the dye was observed by the diameters of blue points. Cells were inoculated into 96-well plates for 2～3 ×10~4 per well and incubated for 24 hours. Medium was changed with different drugs and incubated for another 24 hours. Medium was discarded, dye was added for 30 minutes, then dye was discarded and washed with lotion for 10 minutes, then the optical density of the plates was read on ELISA reader at 570 nm/630nm. Results: All rats survived after administering and no apparent changes induced by drugs were observed. Rats at the low dose showed decrease...
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