";s:4:"text";s:3675:" The drug is eliminated with a mean terminal half-life of approximately 7 hours.
For pharmacokinetic evaluation, QTP and NQTP were administered orally and intravenously to rats at various doses.
However, discrepancies between in vitroand in vivo data are well known for many substrates and could be causedby experimental conditions, interindividual variability, extrahepatic me-tabolism, or nonlinear kinetics (Tucker et al., 2001; Donato and Castell,systemic exposure and lipid-lowering response to simvastatin (Kivisto etal., 2004; Kim et al., 2007), although CYP3A4 possessed a 3- to 9-foldhigher affinity than CYP3A5 for the formation of three major metabolitesof simvastatin in vitro (Prueksaritanont et al., 1997).
The individual variability in phenotype is substantial for bothenzymes, but this variability is linked to genetic polymorphism onlyfor CYP3A5 (Westlind-Johnsson et al., 2003). In addition, the inhibitory constant Ki of ketoconazole on testosterone metabolism was 0.013 ± 0.0038 μmol/L. Conclusions: Genetic variability in CYP2D6 contributes to the interindividual variability in steady-state serum concentrations of N-desalkylquetiapine.
CLwas higher (3-fold) in CYP3A4 microsomes without cytochrome bcompared with CYP3A4 microsomes with coexpressed cyto-both microsomal preparations. Application of the PBPK models for prediction of phenotypic differences in the PKs compared favorably with reported clinical data. Serum measurements of quetiapine and N-desalkylquetiapine performed between October 2007 and July 2008 were retrospectively included from a routine therapeutic drug monitoring database. Conclusions: Dose-adjusted trough levels were determined and correlated with the corresponding genotype.Results: Tacrolimus dose-adjusted trough levels were higher in CYP3A5*3/*3 patients (n = 45) than in *1/*3 plus *1/*1 patients (n = 17), as follows: median and range, 94 (34-398) ng/mL per mg/kg versus 61 (37-163) ng/mL per mg/kg (P < .0001, Mann-Whitney test). The retention times were2.8 min for 7-hydroxyquetiapine, 3.1 min for quetiapine sulfoxide, 5.6 min forine, and 6.9 min for promazine. In total, 927 serum samples from 601 patients were included (all using quetiapine immediate-release tablets). Substrate depletion has some disadvantages comparedwith typical kinetic estimations based on metabolite formation withincreasing substrate concentrations. NQTP administration results in increased systemic exposure and brain distribution compared to QTP administration.
and fed conditions and to determine the effect of food on the pharmacokinetic (PK) properties metabolites, 13-O-desmethyl tacrolimus (13-DMT) (major), 15-O-desmethyl tacrolimus, 31-O-desmethyl tacrolimus (31-DMT), and 12-hydroxy tacrolimus (12-HT), were generated by human liver microsomes and heterologously expressed CYP3A4 and CYP3A5.