Study on Pharmacokinetics and Pharmacodynamics of Oral Colon Targeted pH-Sensitive Hydrogel of Hydrocortisone Sodium Succinate

OBJECTIVE To study the pharmacokinetics and pharmacodynamics of oral colon targeted pH-sensitive hydrogel of hydrocortisone sodium succinate(HSS-GEL). METHODS The plasma concentration changes of HSS-GEL and HSS in the mice were investigated; 2, 4, 6-trinitrobenzene sulfonic acid(TNBS)-induced mouse model of ulcerative colitis(UC) was established, disease activity index(DAI), colon length, myeloperoxidase(MPO) and organ index were used as indicators to investigate the therapeutic effect of HSS-GEL on colitis. RESULTS The results showed that the T_max, C_max and AUC of HSS-GEL were significantly different from those of HSS(P<0.01). The T_max of HSS-GEL was significantly longer than that of HSS, and the time of drug absorption into the blood was significantly delayed. The C_max of HSS-GEL group was significantly lower than that of HSS. The AUC of the HSS-GEL group was 39.38% of the same dose of HSS, indicating that the amount of the drug absorbed into blood was significantly reduced after the HSS was made into HSS-GEL orally. After modeling, DAI, MPO activity and organ index were increased, while the colon was shortened due to the inflammatory reaction, with the treatment of HSS-GEL, DAI, MPO activity and some organ index of mice were significantly decreased comparing with TNBS group(P<0.05 or P<0.01). The degree of reduction of MPO activity and some organ indexes of the mice in the TNBS+HSS-GEL group were significantly greater than those in the TNBS+HSS group, indicating that HSS-GEL had good therapeutic effect on TNBS-induced ulcerative colitis, and the effect was better than that of HSS. CONCLUSION The HSS-GEL prepared has good colon targeting characteristic and colitis treatment effect.