Determination of Doxycycline in Bovine Tissues and Body Fluids by High-Performance Liquid Chromatography Using Photodiode Array Ultraviolet-Visible Detection

Oxytetracycline (OTC) pharmacokinetics were studied in the red pacu (Colossoma brachypomum) following intravenous (i.v.) and intramuscular (i.m.) administration at a dose of 5 mg/kg body weight. OTC plasma concentrations were determined by high-performance-liquid-chromatography (HPLC). A non-compartmental model was used to describe plasma drug disposition after OTC administration. Following i.m. administration, the elimination half-life (t1/2) was 62.65 +/- 1.25 h and the bioavailability was 49.80 +/- 0.01%. After i.v. administration the t1/2 was 50.97 +/- 2.99 h, the Vd was 534.11 +/- 38.58 mL/kg, and CI(b) was 0.121 +/- 0.003 mL/min x kg. The 5 mg/kg i.v. dose used in this experiment resulted in up to 48 h plasma concentrations of OTC above the reported MIC values for some strains of fish pathogens such as Aeromonas hydrophila, A. liquefaciens, A. salmonicida, Cytophaga columnaris, Edwardsiella ictaluri, Vibrio anguillarium, V. ordalii, V. salmonicida and Yeersinia ruckeri. These MIC values are below the susceptible range (4 microg/mL) listed by the National Committee for Clinical Laboratory Standards (NCCLS) as determined by the NCCLS susceptibility interpretive criteria.

Section: Methodsmentioning

confidence: 99%

Pharmacokinetics of oxytetracycline in the red pacu (Colossoma brachypomum) following different routes of administration

Lewbart

1998

“…Doxycycline concentrations were determined by high-performance liquid chromatography using ultraviolet-visible photometric detection according to a method described elsewhere (Riond et al, 1989a). The assay performance was characterized by 96.84 f 0.01% (SD) recovery and a linear response-concentration Values of intercepts with the abscissa (Ka) and ordinate ( l h ) of the double-reciprocal plot were derived by linear regression using SAS (Statistical Analysis System, SAS Institute Inc, Cary, NC).…”

Section: Methodsmentioning

confidence: 99%

Doxycycline binding to plasma albumin of several species

Riond

Riviere

1989

The affinity of doxycycline for crystalline plasma albumin fraction V, originating from sheep, dogs, cats, cows, pigs and humans, was evaluated by means of double-reciprocal and Scatchard plots. Mathematical modelling and weighted least-squares non-linear regression analysis of each Scatchard plot identified one binding component characterized by one high affinity binding site, and a second component attributed to non-specific binding to albumin. Association constants for this binding site ranged from 38,471 +/- 13,369 (SEM) l/mol for the interaction of doxycycline with ovine albumin to 6405 +/- 2375 l/mol for the interaction of doxycycline with human albumin. Statistical evaluation of the results suggested slight species-related differences in the values of association constants. Diphenylhydantoin, phenobarbital or carbamazepine did not displace doxycycline from binding sites on bovine albumin.

“…Photodiode array detection of the HPLC column effluent was used to identify metabolites in serum or urine of both species as previously reported (Riond et al, 1989a;Riond & Kiviere, 1990).…”

Section: Data Analysesmentioning

confidence: 99%

Comparative pharmacokinetics of doxycycline in cats and dogs

Riond

Vaden

Riviere

1990

The disposition of doxycycline hyclate was studied in six adult mixed-breed female cats and six adult mid-sized female dogs following a single intravenous administration of 5 mg/kg body weight. Doxycycline volume of the central compartment, area volume of distribution, volume of distribution at steady state, and total body clearance were significantly smaller in cats. The differences were attributed to more extensive binding of doxycycline to plasma protein including albumin in cats. The significant differences in the volume of distribution and total body clearance were not reflected in elimination half-lives under the conditions of this study (sample size, inhomogeneous population). Doxycycline elimination half-life was 4.56 +/- 0.68 (SEM) h for cats and 6.99 +/- 1.09 h for dogs. Dosage regimens recommended in the veterinary literature were evaluated by the computer program PETDR.