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Table 1 Synovial fluid pharmacokinetic parameters

From: Synovial fluid pharmacokinetics of tulathromycin, gamithromycin and florfenicol after a single subcutaneous dose in cattle

   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
  1. 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.
  2. 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).