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Table 1 Noncompartmental pharmacokinetic parameters for tulathromycin in plasma and the marker residue CP-60,300 in milk of lactating goats following two subcutaneous injections of 2.5 mg/kg tulathromycin at 7-day interval

From: Estimation of tulathromycin depletion in plasma and milk after subcutaneous injection in lactating goats using a nonlinear mixed-effects pharmacokinetic modeling approach

Pharmacokinetic parameters (units) Plasma (injection 2 only) Milk (injection 1) Milk (injection 2)
mean SD mean SD mean SD p value#
Cmax (obs) (ng/mL) 155.211 39.501 1806.280 660.824 1457.238 282.876 0.191
Tmax (obs) (h) 16.828 8.880 15.016 5.240 17.930 9.017 0.574
λz (1/h) 0.013 0.002 0.017 0.006 0.005 0.001 <0.001
T1/2λz (h) 56.421 8.265 51.752 35.768 158.002 40.291 <0.001
AUClast (h*ng/mL) 8050.601 1532.931 61805.331 6351.608 68156.845 12472.633 0.220
AUCinf (h*ng/mL) 9120.588 1599.754 65147.987 7889.685 68978.306 12598.494 0.478
  1. Cmax (obs): observed maximum plasma or milk concentration; Tmax (obs): time to observed maximum plasma or milk concentration after each injection; λz: elimination rate constant; T1/2λz: elimination half-life; AUClast: area under the plasma or milk concentration vs. time curve to the last sampled value; AUCinf: area under the plasma or milk concentration vs. time curve extrapolated to infinity
  2. # p values of Student’s t test of the difference in the milk pharmacokinetic parameters between the first injection and the second injection