Comparative study on 5-bromo-2-fluorobenzonitrile in rat and human plasma protein binding and its metabolism in liver microsomes in vitro / 中国职业医学

ABSTRACT

OBJECTIVE: To study the metabolic characteristics of 5-bromo-2-fluorobenzonitrile in vitro and compare the differences between rats and human,and for the purpose of providing data for poison effect research and extrapolating poison effect of 5-bromo-2-fluorobenzonitrile from animals to human being. METHODS: Equilibrium dialysis method was used to analyze the protein binding ratio of 5-bromo-2-fluorobenzonitrile in the plasma of rats and humans in the groups of low dose,medium dose and high dose which were treated with mass concentration of 5-bromo-2-fluorobenzonitrile at 500,5 000 and 50 000 μg / L respectively. Metabolic incubation systems of SD rat microsomes and human liver microsomes were established in vitro. When the mass concentration of 5-bromo-2-fluorobenzonitrile in the systems was 800 μg / L,the concentration of liver microsome was 0. 5 g / L; after being incubated for 0,10,30,60 and 90 min with the involvement of the regeneration system of nicotinamide-adenine dinucleotide phosphate in the incubation systems,the metabolic reaction was stoped. The residual amounts of 5-bromo-2-fluorobenzonitrile were analyzed and metabolic half-life of 5-bromo-2-fluorobenzonitrile incubating with liver microsomes in vitro was figured out. RESULTS: Protein binding ratio of 5-bromo-2-fluorobenzonitrile in the groups of low dose,medium dose and high dose were( 83. 5 ± 0. 9) %,( 88. 8 ± 0. 3) % and( 88. 6 ± 0. 3) % in rats plasma,and( 85. 2 ± 0. 1) %,( 89. 0 ± 0. 1) % and( 91. 1 ± 0. 4) % in human plasma. Both in rat plasma and human plasma,the protein binding ratio of 5-bromo-2-fluorobenzonitrile in the groups of medium dose and high dose were significantly increased than that in the low-dose group( P < 0. 01). In human plasma,the protein binding ratio of 5-bromo-2-fluorobenzonitrile in the high-dose group significantly increased than that in the medium-dose group( P < 0. 01). In the groups of low dose and high dose,the protein binding ratio of 5-bromo-2-fluorobenzonitrile in human plasma significantly increased than that in rats plasma( P < 0. 01). Absolute differences in protein binding ratio of 5-bromo-2-fluorobenzonitrile between the rat plasma and the human plasma were no more than 2. 5% in the same dose groups. Metabolic half-life of 5-bromo-2-fluorobenzonitrile incubating with rats and human liver microsomes and control solution in vitro were respectively( 58. 6 ± 1. 6),( 59. 2 ± 1. 5) and( 65. 0 ± 6. 3) min,which shows no significant differences( P < 0. 05). CONCLUSION: The potein binding ratio and metabolism of 5-bromo-2-fluorobenzonitrile in liver microsomes in rat plasma is similar to those in human plasma. Both in the plasmas of rats and humans,5-bromo-2-fluorobenzonitrile has high protein binding ratio,and 5-bromo-2-fluorobenzonitrile is not metabolized in liver microsomes of either rats or humans.