Ketoprofen (KTP) and meloxicam (MLX) are non-steroidal anti-inflamatory drugs used extensively in veterinary medicine. The pharmacokinetics of these drugs were studied in eight dogs following a single oral dose of 1 mg/kg of KTP as a racemate or 0.2 mg/kg of MLX. The concentrations of the drugs in plasma were determined by high-performance liquid chromatography (HPLC). There were differences between the disposition curves of the KTP enantiomers, confirming that the pharmacokinetics of KTP is enantioselective. (S)-(+)-KTP was the predominant enantiomer; the S:R ratio in the plasma increased from 2.58 +/- 0.38 at 15 min to 5.72 +/- 2.35 at 1 h. The area under the concentration time curve (AUC) of (S)-(+)-KTP was approximately 6 times greater than that of (R)-(-)-KTP. The mean (+/- SD) pharmacokinetic parameters for (S)-(+)-KTP were characterized as Tmax = 0.76 +/- 0.19 h, Cmax = 2.02 +/- 0.41 microg/ml, t1/2el = 1.65 +/- 0.48 h, AUC = 6.06 +/- 1.16 microg.h/ml, Vd/F = 0.39 +/- 0.07 L/kg, Cl/F = 170 +/- 39 ml/(kg.h). The mean (+/- SD) pharmacokinetic parameters of MLX were Tmax = 8.5 +/- 1.91 h, Cmax = 0.82 +/- 0.29 microg/ml, t1/2lambda(z) = 12.13 +/- 2.15 h, AUCinf = 15.41 +/- 1.24 microg.h/ml, Vd/F = 0.23 +/- 0.03 L/ kg, and Cl/F = 10 +/- 1.4 ml/(kg.h). Our results indicate significant pharmacokinetic differences between MLX and KTP after therapeutic doses.

The purpose of this study was to investigate the pharmacokinetics of ceftriaxone after single intravenous (i.v.), intramuscular (i.m.) and subcutaneous (s.c.) doses in healthy dogs. Six mongrel dogs received ceftriaxone (50 mg/kg) by each route in a three-way crossover design. Blood samples were collected in predetermined times after drug administration. Results are reported as mean +/- standard deviation (SD). Total body clearance (Cl(t)) and apparent volume of distribution (V(z)) for the i.v. route were 3.61 +/- 0.78 and 0.217 +/- 0.03 mL/kg, respectively. Terminal half-life harmonic mean (t(1/2 lambda)) was 0.88; 1.17 and 01.73 h for the i.v., i.m and s.c. routes, respectively. Mean peak serum concentration (C(max)) was 115.10 +/- 16.96 and 69.28 +/- 14.55 microg/mL for the i.m and s.c. routes, respectively. Time to reach C(max) (t(max)) was 0.54 +/- 0.24 and 1.29 +/- 00.64 h for the i.m and s.c. routes, respectively. Mean absorption time (MAT) was 1.02 +/- 0.64 and 2.23 +/- 00.73 h for the i.m and s.c. routes, respectively. Bioavailability was 102 +/- 27 and 106 +/- 14% for the i.m and s.c. routes, respectively. Statistically significant differences were determined in C(max), t(max), MAT and t(1/2 lambda) of s.c. administered ceftriaxone when compared with the i.v and i.m. routes. These findings suggest that once or twice s.c. or i.m. daily administered ceftriaxone should be adequate to treat most susceptible infections in dogs.

The objectives of this work were to compare the pharmacokinetics of erythromycin administered by the intramuscular (i.m.) and intravenous (i.v.) routes between nonlactating and lactating goats and to determine the passage of the drug from blood into milk. Six nonpregnant, nonlactating and six lactating goats received erythromycin by the i.m. (15 mg/kg) and the i.v. (10 mg/kg) routes of administration. Milk and blood samples were collected at predetermined times. Erythromycin concentrations were determined by microbiological assay. Results are reported as mean +/- SD. Comparison of the pharmacokinetic profiles between nonlactating and lactating animals after i.v. administration indicated that significant differences were found in the mean body clearance (8.38 +/- 1.45 vs. 3.77 +/- 0.83 mL/kg x h respectively), mean residence time (0.96 +/- 0.20 vs. 3.18 +/- 1.32 h respectively), area under curve from 0 to 12 h (AUC(0-12)) (1.22 +/- 0.22 vs. 2.76 +/- 0.58 microg x h/mL respectively) and elimination half-life (1.41 +/- 1.20 vs. 3.32 +/- 1.34 h); however, only AUC(0-12) showed significant differences after the i.m. administration. Passage of erythromycin in milk was high (peak milk concentration/peak serum concentration, 2.06 +/- 0.36 and AUC(0-12milk)/AUC(0-12serum),6.9 +/- 1.05 and 2.37 +/- 0.61 after i.v. and i.m. administrations respectively). We, therefore, conclude that lactation affects erythromycin pharmacokinetics in goats.

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In this study the pharmacokinetics and renal safety of gentamicin in healthy dogs was investigated after multiple dosing. Six adult male dogs received once-daily gentamicin (6 mg/kg) intramuscularly for 5 days. Serial blood samples were taken on days 1 and 5 of treatment, and at predose, 1 and 6 h on days 2, 3 and 4. Urinalysis, hematology and serum biochemistry evaluation were carried out before, 7 and 14 days after the first gentamicin administration. Mean value of the main pharmacokinetic parameters were: AUC (microg.h/mL), 97.4 and 100.2; terminal half-life (harmonic mean), 0.76 and 1.01 h; ClB/F (mL/min.kg), 1.24 and 1.10; VD(area)/F (L/kg), 0.084 and 0.10; MRT (h), 1.48 and 1.77; Cmax (microg/mL), 54.5 and 49.2; tmax (h), 0.40 and 0.48 for the first and last dose, respectively. Accumulation was determined as R1 = 0.97 and R2 = 1.22. Mean trough gentamicin serum concentrations were 0.06, 0.07, 0.09, 0.1 and 0.1 microg/mL for the first, second, third, fourth and fifth dose, respectively. Statistically significant increases (P < 0.05) were found for last dose MRT and fourth and fifth trough gentamicin serum concentrations. Laboratory tests detected a slight increase in serum creatinine and urea nitrogen concentrations (one dog), decreased specific urine gravity (one dog) and presence of few granular casts (two dogs). It is concluded that once-daily administration of gentamicin may provide adequate serum levels to treat most susceptible gram-negative infections with little or no nephrotoxicity in dogs.