ISSN:
1573-904X
Keywords:
luteinising hormone-releasing hormone (LH-RH) antagonist
;
cetrorelix
;
pharmacokinetics
;
population PK/PD-modeling
;
testosterone
;
rat
;
dog
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Purpose. Population models for thepharmacokinetic-pharmacodynamic relationship for cetrorelix (CET), a luteinising hormone-releasinghormone (LH-RH) antagonist, and the pharmacodynamic response ontestosterone production were investigated in rats and dogs. Methods. The plasma concentrations of CET and testosterone weredetermined after intravenous and subcutaneous injections. Thepopulation PK/PD-models were developed using P-PHARM software. Results. Absolute bioavailability of cetrorelix was 100% in rats and97% in dogs. In rats, the pharmacokinetics was explained by atwo-compartment model with saturable absorption, while athree-compartment model was used in dogs. Testosterone suppression in both specieswas described by a sigmoid Emax model with maximum effect (Emax)considered as total hormonal suppression. The duration of testosteronesuppression in rats was longer at higher doses. The populationelimination half-lifes after iv-dose were 3.0 h in rats and 9.3 h in dogs.Population mean estimates of IC50 were 1.39 and 1.24 ng/ml in ratsand dogs, respectively. Conclusions. A population pharmacokinetic model was developed toexplain the dissolution rate limited absorption from the injection site.The suppression of testosterone could be described by an indirectinhibitory sigmoid Emax model. In both species 1-2 ng/ml CET inplasma was necessary to suppress testosterone production.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1023/A:1007557207590
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