كتاب Comparative pharmacokinetics of sulfamethazine after intravenous administration in bovine (Bos taurus) and buffalo (Bubalis bubalis) calves

Comparative pharmacokinetics of sulfamethazine after intravenous administration in bovine (Bos taurus) and buffalo (Bubalis bubalis) calves من كتب طب بيطرى Comparative pharmacokinetics of marbofloxacin after a single intramuscular administration at two dosages to camels ( Camelus dromedarius ) R. LARAJE* A. TALMI* R. BOUNAGA
M. BENGOUMI
A. EL HRAIKI
& M. LAURENTIE  * Laboratoire National de Contro ˆ le des Me ́ dicaments Ve ́ te ́ rinaires, Rue Ikhlass, Cite ́ Yakoub El Mansour, Rabat;
Institut Agronomique et Ve ́ te ́ rinaire Hassan II, Rabat, Morocco;  AFSSA Fouge ` res, LERMVD, Unite ́ pharmacocine ́ tique-Pharmacodynamie, Fouge ` res Cedex, France (Paper received 9 December 2005; accepted for publication 20 February 2006) M. Laurentie, AFSSA Fouge ` res, LERMVD, Unite ́ pharmacocine ́ tique-Pharmacodynamie, BP. 90203, 35302 Fouge ` res Cedex, France. E-mail: [email protected] Marbofloxacin is a fluoroquinolone antimicrobial agent used exclusively in veterinary medicine. This agent has a broad- spectrum microbial activity including most aerobic Gram- negative and some aerobic Gram-positive bacteria. Its spectrum of activity and pharmacokinetic profile suggest good tissue penetration making this drug a suitable second choice treatment especially for dermatological and pulmonary infections. Mar- bofloxacin is mainly eliminated in urine in its active form making it a suitable alternative for the treatment of urinary tract infections (Schneider et al. , 1996). A previous study has shown that the main clinical problems in adult dromedaries are dermatological and pulmonary infections whereas in young dromedaries infectious diarrhoea is of major clinical importance (Bengoumi & Faye, 2002). Marbofloxacin might be a suitable antimicrobial agent for the treatment of these diseases in the camel. The pharmacokinetics of marbofloxacin are well documented in bovine species, but not in camels. The purpose of the present study was to investigate the disposition of this fluoroquinolone in camels following administration of a single dose at a dosage of 2 and 4 mg/kg b.w. intramuscularly (i.m.). The study was carried out on five healthy male camels, 5– 13 years old and ranging in body weight from 291 to 535 kg. They were individually stabled and were fed barley (2 kg/day each) and had free access to hay and water. No drugs had been administered previously to these animals. All the camels were administered a 10% aqueous solution of the base form of marbofloxacin (Ve ́ toquinol, Lure, France) at a dose of 4 mg/kg b.w., i.m., in the right thigh. After a wash-out period of 2 weeks, the same animals were administered the same solution at a dose of 2 mg/kg b.w. i.m. in the right thigh. Blood samples (10 mL) were collected from the right jugular vein just before drug administration and at 5, 10, 15, 30, 45 min, 1, 2, 3, 4, 6, 8, 12, 16, 24, 36, 48, 72 and 96 h after administration. Blood samples were centrifuged (2600 g for 10 min) and plasma was stored at ) 20 ° C until analysis. The plasma concentration of marbofloxacin were determined by a reverse phase high-performance liquid chromatography with UV detection (295 nm) using the method described by Schneider et al. (1996). The standard curve of marbofloxacin in camel plasma was linear between 0.1 and 5 l g/mL with a determination coefficient ( r 2 ) of 99.8%. The recovery measured on linear dosage interval was 96%. The intra- and inter-assay coefficients of variation were below 5%. The limit of quantifica- tion was established at 0.1 l g/mL. Both compartmental and statistical moment approaches were used to analyse the plasma concentration–time data for mar- bofloxacin in camels using a nonlinear regression analysis program (Winonlin 4.01; Pharsight Inc., Mountain View, CA, USA). One- and two-compartment open models were tested using first-order absorption with and without a lag time. The best fitting model was selected using Akaike’s Information Criterion (Yamaoka et al. , 1978). Classical pharmacokinetic parameters were calculated using standard equations (Gibaldi & Perrier, 1982). The observed maximum concentration ( C maxobs ) and the time when these concentrations occurred ( t max ) have also been indicated. The relative bioavailability ( F ) was calculated using the equation: ...............
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