Determination of Degradation Level of Antifungal Agent in Mice Serum by High Performance Liquid Chromatography
高效液相色谱法测定抗真菌化合物在小鼠血清中的降解水平

L-4-oxalysinyl-norvalinyl-N3-4-methoxyfumaroyl-L-2, 3-diaminopropanoic acid (I- 677-Nva -FMDP ) is a new tripeptide symhesized in our group. This peptide exhibits potent anticandida Albicans activity. In the presence of serum, the anti fun gal activity of I-677-Nva-FMDP decreases after incubating over 1h. In order to investigate the relationship between the degradation and antifungal activity of I-677-Nva-FMDP, the concentrations of I-677-Nva-FMDP and N3-methoxyfumaroyl-L-2, 3-diaminopropanoic acid (FMDP) were determined at different incubating time in mice serum. The incubating time range was from o to 300 min and the incubating samples were measured at intervals of 30 min. For this measurement reversed-phase HPLC was used and the mobile phase was composed of 8% methanol and 0. 1 % trinuoroacitic acid-triethyl amine buffer (pH 3). In this condition the retention time of FMDP and I-677-Nva-FMDP were 3. 9 min and 16. 5 min respectively. Methanol was superior to other reagents for the removal of protein from the incubating medium and there was not any interference peak before the retention time of I-677-Nva-FMDP. A decrease in concentration of I-677-Nva-FMDP was observed from 0 min to 180 min and no I-677-Nva-FMDP could be detected at 210 min whereas the concentration of FMDP incresed from 30 min to 2h and reached a maximum at 120 min. The results showed that the half life(t1/2) of I-677-Nva-FMDP was 70 min. This result coincided with the antifungal test in vitro.