Pharmacokinetics of two once-daily parenteral cephalexin formulations in dogs.
The aims of this study were to describe and compare the pharmacokinetic profiles and T(>MIC90) of two commercially available once-daily recommended cephalexin formulations in healthy adult dogs administered by the intramuscular (i.m.) route. Six beagle dogs received a 10 mg/kg dose of an 18% parenteral suspension of cephalexin of laboratory A (formulation A) and laboratory B (formulation B) 3 weeks apart. Blood samples were collected in predetermined times after drug administration. The main pharmacokinetic parameters were (mean +/- SD): AUC((0-infinity)), 72.44 +/- 15.9 and 60.83 +/- 13.2 microg.h/mL; C(max), 10.11 +/- 1.5 and 8.50 +/- 1.9 microg/mL; terminal half-life, 3.56 +/- 1.5 and 2.57 +/- 0.72 h and MRT((0-infinity)), 5.86 +/- 1.5 and 5.36 +/- 1.2 h for formulations A and B, respectively. T(>MIC90) was 63.1 +/- 14.7 and 62.1 +/- 14.7% of the dosing interval for formulations A and B, respectively. Median (range) for t(max) was 2.0 (2.0-3.0) h and 3.0 (2.0-4.0) for formulations A and B, respectively. Geometric mean ratios of natural log-transformed AUC((0-infinity)) and C(max) and their 90% confidence intervals (CI) were 0.84 (0.72-0.98) and 0.83 (0.64-1.07), respectively. The plasma profiles of cephalexin following the administration of both formulations were similar. No statistical differences between pharmacokinetic parameters or T(>MIC90) were observed, however, bioequivalence between both formulations could not be demonstrated, as lower 90% CI failed to fell within the selected range of 80-125% for bioequivalence.
Rebuelto
M
M
Farmacología, Departamento de Fisiopatología y Etiopatogenia, Facultad de Ciencias Veterinarias, Universidad de Buenos Aires, Buenos Aires, Argentina. rebuelto@fvet.uba.ar
Montoya
L
L
Kreil
V
V
Ambros
L
L
Waxman
S
S
Albarellos
G
G
Hallu
R
R
D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D019540:Area Under Curve; D002506:Cephalexin / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D002626:Chemistry, Pharmaceutical; D004285:Dogs / Q000378:metabolism*; D004334:Drug Administration Schedule; D005260:Female; D007273:Injections, Intramuscular / Q000662:veterinary; D008297:Male
D000900:Anti-Bacterial Agents; D002506:Cephalexin