Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5797689 | The Veterinary Journal | 2015 | 6 Pages |
â¢Matrix effects were evaluated in an MIC determination of Mycoplasma gallisepticum.â¢Ex vivo PK/PD modeling of valnemulin administered to infected chickens was performed.â¢A dosage of 12.4âmg/kg/day valnemulin was calculated for mycoplasmacidal activity.
Pharmacokinetic and pharmacodynamic (PK/PD) indices against Mycoplasma gallisepticum (MG) S6 were investigated in an ex vivo PK/PD model following oral administration of valnemulin to chickens co-infected with M.âgallisepticum and Escherichia coli. The minimum inhibitory concentrations (MICs) for valnemulin against MG S6 in artificial medium and chicken serum were determined. In vitro time-killing curves were established according to a series of multiples of the MIC value in an artificial medium, and ex vivo time-killing curves were established in serum samples obtained from infected chickens at different time points after oral administration with an initial titer of 1âÃâ106 color change units (CCU)/mL MG S6. The sigmoid Emax model was used to provide 24âh area under concentration-time curve/minimum inhibitory concentration ratios (AUC0-24h/MIC) for mycoplasmastasis, mycoplasmacidal activity and mycoplasmal elimination, respectively.The inoculum size and micro or macro methods exhibited little effect on MIC determination of MG, whereas matrix had a large effect. The rapid killing activity observed in in vitro time-killing curves seems to indicate that valnemulin was mycoplasmacidal and concentration dependent against MG. The AUC0-24h/MIC ratio for mycoplasmacidal activity and mycoplasmal elimination was 1321âh and 1960âh, respectively. A dosage regimen of 12.4âmg/kg/day and 18.3âmg/kg/day valnemulin was calculated for mycoplasmacidal activity and mycoplasmal elimination against MG S6, respectively.