Studies On The Pharmacokinetics Of Pefloxacine Mesylate In Goats And Pharmacodynamics Of Pefloxacine Mesylate In Chickens

The study was divided into three parts. The first studied the pharmacokinetics of Pefloxacine Mesylate (PM) in goats; the second studied the antibacterial activity in vitro of PM; the third studied the pharmacodynamics of PM against artificially infected Escherichia coli in chickens.1 Goats were treated with a single dosage of PM (10 mg/kg) intravenously and rapidly, while the blood samples were collected from jugular vein within 8 hour post giving drug. The concentrations of PM in serum were determined by high performance liquid chromatography (HPLC). The results showed that the two-compartment open model with first-order disabsorption factor adequately describes concentrations of PM in serum disposition and the best concentration-time equations are: C = 9.3680e ?5 .6806 t + 9.4885e?0.4393t. The primary pharmacokinetic parameters of PM are: t1/2α=0.1678 h±0.1298 h, t1/2β=1.6322 h±0.3189 h, AUC=24.7542μg·mL-1·h±6.4560μg·mL-1·h, Vd=0.9676 L·kg-1±0.1498 L·kg-1, CLB=0.4219 L·kg-1·h-1±0.0832 L·kg-1·h-1. It will be seen that the distribution of PM in vivo is rapid and abroad, and the elimination of PM in vivo is rapid.2 Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of PM, Ciprofloxacin·HCl and Norfloxacin against Staphylococcus aureus, Streptococcus agalactiae, Escherichia coli, Salmonella and Pseudomonas aeruginosa were detemined by two-fold diltution method in vitro.The MICs of PM were 1, 2, 0.25, 0.5, 8μg/mL, respectively. The MBCs of PM were 1, 4, 1, 0.5, 8μg/mL, respectively. The MICs of Ciprofloxacin·HCl were 0.5, 0.03, 0.03, 0.03, 1μg/mL. The MBCs of Ciprofloxacin·HCl were 1, 0.12, 0.12, 0.06, 4μg/mL. The MICs of Norfloxacin were 2, 2, 1, 1, 8μg/mL. The MBCs of Norfloxacin were 2, 4, 1, 1, 32μg/mL. The results showed that the antimicrobial action of PM against Gram-negative bacteria (G-) was very good and against Gram-positive bacteria (G+) was also good, but against Pseudomonas aeruginosa was weak. The antimicrobial action of PM was weaker than Ciprofloxacin·HCl, but better than Norfloxacin.3 At first, the chickens were infected by Escherichia coli artificially. All the therapeutic groups of chickens were medicated for 3 days via drinking water with PM (25 mg/L, 50 mg/L, 100 mg/L) and Ciprofloxacin·HCl (50 mg/L). It will be seen that the cure rates of the high- dosage group of PM and Ciprofloxacin·HCl group were higher than that of middle-dosage group and low-dosage group of PM (P<0.05). The effect of weigh gain to chickens of the high-dosage group of PM was equivalent to that of Ciprofloxacin·HCl group (P>0.05), and obviously higher than that of infective control group (P<0.01). The effect of weigh gain to chickens of middle-dosage group and low-dosage group of PM were obviously lower than that of high-dosage group of PM and Ciprofloxacin·HCl group (P<0.05或0.01). The results showed that the curative effect of the middle-dosage group and low-dosage group of PM were not ideal, but the curative effect of the high-dosage group of PM and Ciprofloxacin·HCl group were good.