title: Bayesian estimation of p-aminohippurate clearance by a limited sampling strategy.
abstract: This study describes a methodology to calculated p-aminohippurate (PAH) clearance (CL) and volume of distribution (V) with both the population parameters and one or two samples taken during the disposition and the elimination phase after a single intravenous infusion. The computer program P-PHARM was used, and a log-normal distribution and a heteroscedastic residual error distribution were assumed. Ninety-six patients with and without renal insufficiency were available for analysis, and a two-compartment model was used for data modeling. Population parameters were evaluated for 70 patients (mean number of observed concentration per individual, 6) by a three-step approach. In step 1, the computer program was used to estimate the average pharmacokinetic parameters without taking into account the demographic and/or biological factors. In step 2, the relationship between the posterior individual estimates and the covariables was investigated with multiple linear stepwise algorithm. In step 3, the population parameters were re-estimated considering the relationship with the covariables. From the regression performed in step 2, the following covariables were included: serum creatinine, body surface area, and body weight. The population averages of CL and V were 30.7 +/- 2.36 L/h and 10.6 +/- 1.29 L, respectively. To evaluate the predictive performance of the population parameters, the remaining 26 patients were used. The population parameters combined with one or two individual PAH plasma concentrations led to a bayesian estimation of individual CL and V. This estimation was compared with the classical procedure of parameter estimation (individual fitting from multiple blood samples).(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Laboratoire de Pharmacocinétique, Faculté de Pharmacie, Montpellier, France.
authors.forename: J M
authors.initials: JM
authors.lastname: Kinowski
authors.forename: M
authors.initials: M
authors.lastname: Rodier
authors.forename: F
authors.initials: F
authors.lastname: Bressolle
authors.forename: D
authors.initials: D
authors.lastname: Fabre
authors.forename: V
authors.initials: V
authors.lastname: Augey
authors.forename: J L
authors.initials: JL
authors.lastname: Richard
authors.forename: M
authors.initials: M
authors.lastname: Galtier
authors.forename: R
authors.initials: R
authors.lastname: Gomen
mesh_terms: D000328:Adult; D000368:Aged; D001499:Bayes Theorem; D003920:Diabetes Mellitus / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D006801:Humans; D007700:Kinetics; D008297:Male; D008433:Mathematics; D008875:Middle Aged; D009765:Obesity / Q000378:metabolism; D013997:Time Factors; D010130:p-Aminohippuric Acid / Q000378:metabolism / Q000493:pharmacokinetics*
chemical_list: D010130:p-Aminohippuric Acid