Studies On Protein Binding Rate And Marker Residue Of Kuianchun

Kuianchun is a new drug of Quinoxlines developed by Lanzhou institute of animal sciences and veterinary pharmaceutics of Chinese academy of agricultural sciences. The previous studies showed that the toxicity and residue of Kuianchun were lower than those of olaquindox and others. In this study, the protein binding rate was evaluated by the equilibrium dialysis, the major excretion and the mark of residue were measured by RP-HPLC. The aims were to provide the data for clinic and residue detection and to provide evidences for evaluation of clinical safety on Kuianchun.RESULTS: (1) At concentration of 22.0μg/mL, 5.5μg/mL and 1.1μg/mL in buffer, the protein binding rates of Kuianchun were 66.96±1.59%, 75.30±1.92%, 84.41±0.87%respectively. The equilibrium dialysis time was 30±2h. (2) At concentration of 20.0μg/mL,5.0μg/mL and 1.0μg/mL in buffer, the protein binding rates of Quinocetone were 46.96±1.59%, 55.30±1.92%, 54.41±0.87% respectively. The equilibrium dialysis time was 30±1 h. (3) At the dose of 200 mg/kg.B.W, over 61% Kuianchun in chicken was excreted with the feces during 72 hours. (4) The Quinoxaline-2-Carboxylic acid was one of the marker residues of Kuianchun. Measured conditions of RP-HPLC to Quinoxaline-2-Carboxylic acid in chicken were ZORBAX Eclipse XDB C18 chromatographic column (250 mm×4.6 mm, 5μm), the mobile phase of 1 % formic acid–methyl alcohol (40/60, v/v), the flow rate of 1.0 mL·min-1, the UV detecting wavelength of 320 nm.CONCLUSION: (1) The equilibrium dialysis time was 30±3h both of Kuianchun and Quinocetone. There was a relationship among the equilibrium time and drug structure and molecular weight. (2) The protein combined with drug was terminated at the saturation. Then, the protein binding rate was decreased with increasing of drug concentration. (3) The protein binding rate of Quinocetone was lower than that of Kuianchun. (4) The much of Kuianchun in chicken was excreted with feces. (5) Quinoxaline-2-Carboxylic acid was one of the marker residues of Kuianchun.