Table 1.
Synovial fluid pharmacokinetic parameters
| Florfenicol | Gamithromycin | Tulathromycin | |||||
|---|---|---|---|---|---|---|---|
| Mean | SD | Mean | SD | Mean | SD | ||
| C max | mcg/mL | 2.71 | 0.93 | 0.14 | 0.11 | 0.79 | 0.57 |
| T max | hr | 7 | 2 | 8 | 0 | 19 | 10 |
| λz | /hr | 0.0115 | 0.0035 | 0.0099 | 0.0038 | 0.0077 | 0.0038 |
| t ½λz | hr | 64.9 | 20.1 | 77.9 | 30.0 | 109.0 | 53.9 |
| AUC last | mcg*hr/mL | 142.0 | 17.5 | 6.2 | 2.8 | 49.7 | 29.1 |
| AUC 0-inf | mcg*hr/mL | 154.0 | 26.2 | 6.5 | 2.9 | 57.6 | 28.2 |
| AUC % Extrap | 7.1 | 6.3 | 6.2 | 2.8 | 18.1 | 12.1 | |
| AUMC 0-obs | mcg*hr2/mL | 7623 | 2577 | 331 | 122 | 3323 | 1577 |
| AUMC 0-inf | mcg*hr2/mL | 11860 | 7054 | 469 | 124 | 6490 | 1311 |
| MRT 0-obs | hr | 53.5 | 15.4 | 55.9 | 14.2 | 71.7 | 14.4 |
| MRT 0-inf | hr | 74.1 | 32.9 | 75.2 | 12.3 | 136.5 | 65.0 |
Tmax: time of peak serum drug concentration; Cmax: peak drug concentration; t1/2: apparent elimination half-life calculated as ln(2)/λz, λz being the first order rate constant associated with the terminal portion of the time-concentration curve; AUC0-obs: area under the time-concentration curve from time zero to the last observed concentration; AUC0-inf: area under the time-concentration curve from time zero extrapolated to infinity; AUMC0-obs: area under the moment curve from time zero to the last observed concentration; AUMC0-inf: area under the moment curve from time zero extrapolated to infinity; MRT0-obs: Mean Resident Time calculated as AUMC0-obs /AUC0-obs; MRT0-inf: Mean Residence Time calculated as AUMC0-inf /AUC0-inf.
Mean pharmacokinetic parameters in synovial fluid estimated via noncompartmental analysis after SC administration of florfenicol (40 mg/kg), gamithromycin (6 mg/kg), and tulathromycin (2.5 mg/kg) (n = 4/group).