Pharmacokinetics Of Cyadox In Swines, Broilers, Carp,Rats And Humans

Cyadox is a new kind of antimicrobial growth-promoter of quinoxalines. Compared with similar drugs of quinoxalines, cyadox has broader antimicrobial spectrum and significantly promotes animal growth and improves feed utilization. Studies have shown that cyadox can effectively promote the growth of livestock, poultry and carp, while the lower toxicity compared with similar drugs, with good development prospects. Pharmacokinetic studies are an important research content of R&D of a new veterinary. In this study, equilibrium dialysis method was used to determine the plasma protein binding rate of cyadox with chicken, carp and rat, which provides basic information for revealing its role characteristics and dynamics in vivo; A blood pharmacokinetic studies of three-doses cyadox in swines, broilers, carp, rats and humans were conducted, calculating pharmacokinetic parameters of cyadox and its metabolites in different animals and fitting the concentration-time curve, and revealing the metabolism and kinetics characteristics of cyadox and its metabolites in five kinds of animals. Cyadox and its metabolites which present in human plasma, urine and fecal sample after orally administration were determined. The metabolites in plasma, feces and urine samples of some time points during the experiment were identified. Clarify metabolism and pharmacokinetic characteristics of cyadox in human and its similarities and differences compared with food animals, observing possible adverse effects caused by cyadox on the human body. In vitro metabolism studies of cyadox, human liver microsomes was used as the experimental materials. The results were compared with existing metabolic results of cyadox in vivo and vitro of target animals as well as experimental animals. We also aim to check whether new metabolites were generated and to compare differences between species.1. Determination of plasma protein binding rate of cyadox with broiler, carp and rat plasmaPlasma protein binding rate is an important parameter of drug in the body affecting directly drug pharmacological and toxicity effects. In this study, equilibrium dialysis method combined with HPLC was used to determine plasma protein binding rate of cyadox with rat, carp and chicken plasma. Dialysis will reach equilibrium within forty-eight hours. When cyadox concentrations were0.05,0.5and1.0mg/L, the protein binding rate of cyadox with rats, carp and chicken plasma was67.23±1.47%,67.13±0.34%,60.97±0.63%;53.53±1.66%,41.66±1.36%,39.82±1.01%and37.30±0.98%,34.74±1.19%,32.54±1.74%. The results show that cyadox belonging to moderate plasma protein binding drugs in rat plasma, may not be used of the drugs into the body play a role in free form, cyadox belong low plasma protein binding drugs in broiler and carp plasma, it will be used of the drugs into the body play a role in free form.2. Pharmacokinetic studies of cyadox in swines, broilers, carp and rats after orally administrationTo investigate the characteristics of absorption, distribution and elimination of different doses cyadox in the four kinds of animals, this experiment studied variation with time of cyadox and its five metabolites in swine, broiler, carp and rat plasma after oral administration based on quantitative analysis method for cyadox and its five metabolites in the pig, chicken, carp and rat plasma. Twenty-four cross-bred (Duroc×Landrace×Large) swine randomly assigned to three groups, was orally administrated with a cyadox suspension at the dose of10,40and100mg/kg body weight. About3-4mL blood sample were obtained from the anterior vena cava at different time points after administration. Thirty broilers randomly assigned to three groups, was orally administrated with a cyadox suspension at the dose of50,100and200mg/kg body weight. About2mL blood sample were obtained from the wing vein at different time points after administration. Two hundred and ten carps randomly assigned to three groups, was orally administrated with a cyadox suspension at the dose of10,20and40mg/kg body weight. About3mL blood sample were obtained from the tail vein at different time points after administration. Ninety rats randomly assigned to three groups, was orally administrated with a cyadox suspension at the dose of100,300and500mg/kg body weight. About0.5ml blood sample were obtained from the retinal vein at different time points after administration. Separated plasma and determined drug concentration in plasma using HPLC, and calculated pharmacokinetic parameters using software of Winnonlin5.2.Swine: Five kinds of compounds were detected in swine plasma. They are Cy0, Cy1, Cy2, Cy4and Cy6. Cy0can be detected at0.75h and Cy1, Cy4and Cy6can be detected at4h after administration at the dose of10mg/kg body weight, Cy0can be detected at 0.17h after administration at the dose of40and100mg/kg body weight. Cyl, Cy4and Cy6can be detected at4h and Cy2can be detected at5h after administration at the dose of40mg/kg body weight. Cy2can be detected at2h and Cyl, Cy4and Cy6can be detected at4h after administration at the dose of100mg/kg body weight. The peak concentration (ug/mL), elimination half-life (h) and the area under the concentration-time curve (h·μg·mL-1) of CyO after orally administration at dose of40mg/kg body weight were0.04,7.41and0.19, and Cy6were0.17,9.04and2.02. The results showed that cyadox and metabolites were absorbed rapidly, less and widely distributed, and Cy0eliminated faster than its metabolites. At different doses, metabolite concentrations were higher than the concentration of parent drug. The elimination half-life of CyO, Cyl, Cy2and Cy4with increasing dosage had no significant changes, suggesting that they may follow linear kinetics in vivo. The elimination half-life of Cy6at different doses and extended as the dose increased, suggesting that it may have the nonlinear dynamics in vivo. The results revealed cyadox kinetic characteristics and dose-dependent in swine, which provided a scientific basis for the further study about cyadox pharmacological, and toxicological characteristics and clinical efficacy and safety.Broilers:Two kinds of compound were detected in broiler plasma. They are Cy0and Cy6. Cy6can be detected at0.5h after administration at the dose of50and100mg/kg body weight. CyO and Cy6can be detected at0.17and0.5h respectively after administration at the dose of200mg/kg body weight. The peak concentration (μg/ml), elimination half-life (h) and the area under the concentration-time curve (h·μg·mL-1) of CyO after orally administration at dose of200mg/kg body weight were0.034,2.91and0.07, and Cy6were0.039,3.36and0.09. The results showed that cyadox and metabolites were absorbed rapidly, less and widely distributed, and CyO was eliminated faster than its metobolites. At different doses, metabolites concentrations were higher than the concentration of parent drug. The elimination half-life of Cy6with increasing doses had no significant changes, suggesting that they may follow linear kinetics in vivo. The results reveal that cyadox kinetic characteristics had dose-dependent in broilers, and provided a scientific basis for the further study cyadox pharmacological, toxicological characteristics and clinical efficacy and safety.Carp:Three kinds of compounds were detected in carp plasma, they are Cy0, Cy1and Cy6. Cy6can be detected after administration at the dose of10mg/kg body weight. Cyl and Cy6can be detected after administration at the dose of20and40mg/kg body weight. Cy0can be detected at0.25h after administration at the dose of40mg/kg body weight. Cyl and Cy6can be detected at1h after administration in three doses. The peak concentration (μg/ml), elimination half-life (h) and the area under the concentration-time curve (h·μg·mL-1) of CyO after orally administration at the dose of40mg/kg body weight were0.063,5.41and0.49, Cy1were0.069,5.56and0.52, and Cy6were0.061,8.68and0.64. The results showed that cyadox and metabolites absorbed rapidly, less and widely distributed, and CyO was eliminated faster than its metabolites. At different doses, metabolites concentrations were higher than the concentration of parent drug. The concentrations of metabolites were increaseed with increasing dose. The elimination half-life of Cyl and Cy6had no significant changes with increasing dose, suggested that they may follow linear kinetics in vivo. The results revealed cyadox kinetic characteristics had dose-dependent in carp, and provided a scientific basis for the further study cyadox pharmacological, toxicological characteristics and clinical efficacy and safety.Rats:The results showed that four kinds of compounds were detected in rat plasma. They are CyO, Cy1, Cy4and Cy6. CyO can be detected at0.75h after administration at the dose of100and0.17h at the dose of300and500mg/kg body weight. Cyl, Cy4and Cy6can be detected at2h after administration at the dose of100mg/kg body weight. Cyl and Cy4can be detected at1h and Cy6at2h after administration at the dose of300and500mg/kg body weight. The peak concentration (μg/ml), elimination half-life (h) and the area under the concentration-time curve (h·μg·mL-1) of CyO after orally administration at the dose of100mg/kg body weight were0.10,6.35and0.51, and Cy6were0.22,8.50and2.28. The results showed that cyadox and metabolites absorbed rapidly, less and widely distributed, and CyO was eliminated faster than its metobolites. At different doses, metabolite concentrations were higher than the concentration of parent drug. The elimination half-life of CyO, Cy1and Cy4were extended at different doses with increasing dose, suggested that it may followed the nonlinear dynamics in vivo. The elimination half-life of Cy6had no significant changes increased with dose, showed that they may follow linear kinetics in vivo. The results revealed cyadox kinetic characteristics and dose-dependent in rats, and provided a scientific basis for further study cyadox pharmacological, toxicological characteristics and clinical efficacy and safety.3. Pharmacokinetics of cyadox in human and its vitro metabolism in human liver microsomesIn vitro metabolism of cyadox was researched in human liver microsomes used human liver microsomes as the experimental materials. Differential spectroscopy was used to detect CYP450activity and determine content. Furthermore, using nifedipine as probe substrates related metabolic enzymes of cyadox to verify the activity of cyadox metabolic enzymes. The results showed that human liver microsomes had a maximum absorption peak at450nm in the UV spectrum, nifedipine in human liver microsomes can be metabolized to oxidized nifedipine and can be used for metabolism studies of cyadox. Cyadox can be metabolized into four (Cyl, Cy2, Cy13and Cy15) metabolites in human liver microsomes, Cyl and Cy2were the main metabolites. No new metabolite was found in the study. The main metabolic pathway is oxygen and hydrolysis of the side chain amide bond. Metabolic pathways and methods had no significant differences compared with food animals and experimental animals.Sixteen healthy subjects were randomly divided into treatment group and control group, treatment group was10people, taking a single oral dose cyadox (15mg/kg BW) capsules. Control group was6people, taking a single oral dose of starch (15mg/kg BW) capsules. About2ml blood sample were obtained from the anterior vena cava at different time points after administration. Using HPLC to detect cyadox and its metabolites and use non-compartment model with statistical moment principles to calculated pharmacokinetic parameters of cyadox and its metabolites. Collection of feces and urine in different time periods after administration to calculate the amount of drugs recovered. Meanwhile, the ECG, blood pressure, pulse, temperature and other physiological indicators of the test subjects were measured before and after administration. The results showed that three kinds of metabolites were detected in human plasma. They were CyO, Cyl and Cy6. CyO can be detected at0.5h after administration and Cyl and Cy6can be detected at6h after administration. The peak concentration (μg/ml), elimination half-life (h) and the area under the concentration-time curve (h·μg·mL-1) of Cy1after orally administration at THE dose of15mg/kg body weight were0.068,8.34and0.72, and Cy6were0.156,11.8and2.04. Absorption and elimination of cyadox were relatively faster and absorption was less, metabolite is the major form in human. Parent drug and elewen metabolites (Cyl, Cy2, Cy4, Cy5, Cy6, Cy7, Cy8, Cy10, Cy13, Cy14and Cy15) were detected in urine and parent drug and ten metabolites (Cyl, Cy2, Cy4, Cy6, Cy7, Cy8, Cy10, Cy12, Cy13and Cy15) were detected in feces. Cyadox was the main form of the drug recovered in the feces and urine, and the amount of drug recovered in feces is far more than the amount in the urine. Total recovery of drug in feces and urine is (36.13±2.22%). Subjects’ physiological and biochemical indicators did not change significantly before and after administration and within the normal physiological range. The results showed that cyadox can be metabolized rapidly to various metabolites, and cyadox metabolic pathways had no significant differences compared with experimental animals and food animals. Cyadox has not apparent adverse effects on the human body.