Interspecies comparisons of plasma half‐life of trimethoprim in relation to body mass

Abstract

The relationship between body mass and plasma half-life of trimethoprim was studied in 10 different species of animals and man using published data. Log half-life was positively and significantly correlated to log body mass based on individual measurements in herbivorous animals (n = 23, P < 0.01), in herbivorous animals+pigs (n = 29, P < 0.01), in ungulates (n = 27, P < 0.01), in ruminants (n = 16, P < 0.01) and in non-herbivorous mammals, except pigs (n = 6, P < 0.05). The correlation was described by the allometric equations: t 1/2 beta = 27 W0.26 in herbivorous animals and t 1/2 beta = 125 W0.32 in non-herbivorous animals except pigs.

Allometric analysis of ciprofloxacin and enrofloxacin pharmacokinetics across species

“…Because most pharmacokinetic parameters are dependent on physiologic functions, it is possible to compare these parameters among species on the basis of allometric relationships, i.e. where y is the value of the pharmacokinetic parameter and x the body weight (Boxenbaum, 1982; Riond & Riviere, 1990; Pashov et al. , 1997; Riviere et al.…”

“…A number of physiologic factors other than basal metabolism can modify these biochemical/physiological relationships. These factors include change in protein binding, saturation of drug elimination processes, diet, genetic polymorphism, drug‐induced alterations in physiologic processes, biotransformation, interspecies differences in enterohepatic circulation, and tubular reabsorption as influenced by urinary pH (Mellett, 1969; Williams, 1973; Sorgel, 1989; Pashov et al. , 1997; Riviere et al.…”

“…, 1997). Differences in pharmacokinetic parameters and biologic activity of drugs among species may be related to physicochemical interactions of drugs with food, or to biodegradation of compounds in the rumen, caecum, or colon (Baggot, 1977, 1980, 1990; Pashov et al. , 1997).…”

Efficacy of trimethoprim‐sulfadoxine against Escherichia coli in a tissue cage model in calves

“…administration [Davitiyananda & Rasmussen, 1974 (1.2 h); White et al ., 1981 (1 h); Shoaf et al ., 1989 (0.9 h); Kaartinen et al ., 1999 (1.2 h)]. Some authors report longer half‐lives [Clarke et al ., 1989b (3.4–4 h); Pashov et al ., 1997 (2.4 h)]. Methodological differences for the determination of plasma half‐lives and/or influence of breed, diet or rearing conditions may account for the observed variations.…”

Allometric analysis of the pharmacokinetics of four cephalosporin antibiotics in mammals

“…It has also been used in drug development (Mahmood & Balian, 1999) and for comparison of pharmacokinetic characteristics of different substances among species (Dinev, 2008). The allometric scaling is usually conducted using data for animal species, belonging to taxonomic groups with similar physiological characteristics as birds or mammals (herbivores or carnivores) (Pashov et al, 1997;Dinev, 2008;Haritova & Lashev, 2009;. This is based on interspecies differences in the physiology and it is aimed at predicting the specific pharmacokinetic properties of the drugs with high accuracy.…”