[Synthesis of 2-hydroxyl-5-butyramidobenzoic acid and its effect on acetic acid-induced colitis in rats].

OBJECTIVE: To study the method for synthesis of 2-hydroxyl-5- butyramidobenzoic acid and test its effect on acetic acid-induced colitis in rats. METHODS: 2-hydroxyl-5-butyramidobenzoic acid was synthesized from 5-aminosalicylic acid and butyric acid by amidation, esterification and hydrolization. The effect of 2-hydroxyl-5-butyramidobenzoic acid on acetic acid enema-induced colitis in rats was investigated. RESULTS: The structure of 2-hydroxyl-5-butyramidobenzoic acid was identified by IR and 1H-NMR. After treatment with acetic acid, the colon mucosal damage index (CMDI), fecal occult blood (OB) test, and activity of myelperoxidase (MPO) increased significantly in the rats as compared to the control levels. 2-hydroxyl-5- butyramidobenzoic acid obviously reduced the CMDI and OB, and reduced the level of MPO in the rats with colitis. CONCLUSION: The synthesis of 2-hydroxyl-5-butyramidobenzoic acid requires only mild conditions with simple procedures, and the synthesized 2-hydroxyl-5-butyramidobenzoic acid shows obvious therapeutic effects on mucosal damage of in rats with acetic acid-induced colitis.

[Preparation of sustained release multivesicular liposome for thymopentin and preliminary study on its pharmacokinetics in rats].

To optimize the formulation and preparation method of multivesicular liposome of thymopentin and to investigate its pharmacokinetics in rats, the multivesicular liposome of thymopentin was prepared by double emulsification method and the formulation was optimized by orthogonal design. The release characteristics of thymopentin from multivesicular liposome in PBS (pH 7.4) and in plasma were investigated. The multivesicular liposome of thymopentin labeled with fluorescein isothiocyanate was prepared by double emulsification method. Its pharmacokinetics was evaluated following intramuscular injection in rats. The optimal formulation of multivesicular liposome of thymopentin were formulated with 7.5% glucose in aqueous phase and 2.25 mol x L(-1) triolein, 2.68 mol x L(-1) DPPG and 16.96 mol x L(-1) DOPC in organic phase. The entrapment efficiency of the multivesicular liposome of thymopentin was above 85% and the mean particle size was about 22 microm. The in vitro release of thymopentin from multivesicular liposome in PBS (pH 7.4) and in plasma was found to be in a sustained manner. The release curves were fitted to Higuchi equation. The pharmacokinetics following intramuscular injection of the multivesicular liposome of thymopentin labeled with fluorescein isothiocyanate in rats showed that the peak concentration of thymopentin was lower and elimination of it was slower significantly than that of thymopentin labeled with fluorescein isothiocyanate solution in the same dose. The plasma concentration of thymopentin maintained above quantitative limitation at 120 h after administration of multivesicular liposome of thymopentin. The optimized formulation and preparation technology of multivesicular liposome of thymopentin with higher entrapment efficiency are feasible with good reproducibility. Multivesicular liposome of thymopentin showed significant sustained-release property following intramuscular injection in rats.