TY - JOUR
T1 - Interspecies Differences and Scaling for the Pharmacokinetics of Xanthine Derivatives
AU - TSUNEKAWA, YOSHIMI
AU - HASEGAWA, TAKAAKI
AU - NADAI, MASAYUKI
AU - TAKAGI, KENZO
AU - NABESHIMA, TOSHITAKA
PY - 1992/7
Y1 - 1992/7
N2 - Abstract— Pharmacokinetic characteristics of the new xanthine bronchodilators, enprofylline and 1‐methyl‐3‐propylxanthine (MPX), were investigated in mice, rats, guinea‐pigs, rabbits and dogs. The possibility of an interspecies pharmacokinetic scale was also evaluated. The concentration of these two drugs in plasma and urine was determined by HPLC. Pharmacokinetic parameters were calculated using model‐independent methods. The disappearance curves of the two drugs from plasma varied markedly among animal species. Interspecies differences in the plasma protein binding of each drug were observed for all animals in the study. Differences in the biotransformation of enprofylline and MPX were also confirmed among the various animal species: enprofylline is mainly excreted in an unchanged form in urine while MPX follows a non‐renal route of elimination. In all animals, the renal clearance for enprofylline was greater than the glomerular filtration rate, indicating active tubular secretion. Significant allometric relationships were seen between the values of total body clearance and steady state volume of distribution for both total and unbound enprofylline and species body weight, but similar correlations could not be recognized for MPX. Renal clearance of enprofylline was also closely correlated with species body weight, suggesting no interspecies difference with relation to affinity and/or capacity for the active tubular secretion mechanism of enprofylline. Our findings suggest that xanthine derivatives, including enprofylline, are mainly eliminated via the kidney, and an estimate of the basic pharmacokinetics in man can be obtained from data in experimental animals. 1992 Royal Pharmaceutical Society of Great Britain
AB - Abstract— Pharmacokinetic characteristics of the new xanthine bronchodilators, enprofylline and 1‐methyl‐3‐propylxanthine (MPX), were investigated in mice, rats, guinea‐pigs, rabbits and dogs. The possibility of an interspecies pharmacokinetic scale was also evaluated. The concentration of these two drugs in plasma and urine was determined by HPLC. Pharmacokinetic parameters were calculated using model‐independent methods. The disappearance curves of the two drugs from plasma varied markedly among animal species. Interspecies differences in the plasma protein binding of each drug were observed for all animals in the study. Differences in the biotransformation of enprofylline and MPX were also confirmed among the various animal species: enprofylline is mainly excreted in an unchanged form in urine while MPX follows a non‐renal route of elimination. In all animals, the renal clearance for enprofylline was greater than the glomerular filtration rate, indicating active tubular secretion. Significant allometric relationships were seen between the values of total body clearance and steady state volume of distribution for both total and unbound enprofylline and species body weight, but similar correlations could not be recognized for MPX. Renal clearance of enprofylline was also closely correlated with species body weight, suggesting no interspecies difference with relation to affinity and/or capacity for the active tubular secretion mechanism of enprofylline. Our findings suggest that xanthine derivatives, including enprofylline, are mainly eliminated via the kidney, and an estimate of the basic pharmacokinetics in man can be obtained from data in experimental animals. 1992 Royal Pharmaceutical Society of Great Britain
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U2 - 10.1111/j.2042-7158.1992.tb05471.x
DO - 10.1111/j.2042-7158.1992.tb05471.x
M3 - Article
C2 - 1357141
AN - SCOPUS:0026625624
VL - 44
SP - 594
EP - 599
JO - Journal of Pharmacy and Pharmacology
JF - Journal of Pharmacy and Pharmacology
SN - 0022-3573
IS - 7
ER -