title: A novel in vitro allometric scaling methodology for aldehyde oxidase substrates to enable selection of appropriate species for traditional allometry.
abstract: 1. Failure to predict human pharmacokinetics of aldehyde oxidase (AO) substrates using traditional allometry has been attributed to species differences in AO metabolism. 2. To identify appropriate species for predicting human in vivo clearance by single-species scaling (SSS) or multispecies allometry (MA), we scaled in vitro intrinsic clearance (CLint) of five AO substrates obtained from hepatic S9 of mouse, rat, guinea pig, monkey and minipig to human in vitro CLint. 3. When predicting human in vitro CLint, average absolute fold-error was ≤2.0 by SSS with monkey, minipig and guinea pig (rat/mouse >3.0) and was <3.0 by most MA species combinations (including rat/mouse combinations). 4. Interspecies variables, including fraction metabolized by AO (Fm,AO) and hepatic extraction ratios (E) were estimated in vitro. SSS prediction fold-errors correlated with the animal:human ratio of E (r2= 0.6488), but not Fm,AO(r2= 0.0051). 5. Using plasma clearance (CLp) from the literature, SSS with monkey was superior to rat or mouse at predicting human CLpof BIBX1382 and zoniporide, consistent with in vitro SSS assessments. 6. Evaluation of in vitro allometry, Fm,AOand E may prove useful to guide selection of suitable species for traditional allometry and prediction of human pharmacokinetics of AO substrates.
authors.affiliation: a Department of Pharmacology , Vanderbilt University School of Medicine , Nashville , TN , USA and.
authors.forename: Rachel D
authors.initials: RD
authors.lastname: Crouch
authors.affiliation: b Q2 Solutions, Bioanalytical and ADME Labs , Indianapolis , IN , USA.
authors.forename: J Matthew
authors.initials: JM
authors.lastname: Hutzler
authors.affiliation: a Department of Pharmacology , Vanderbilt University School of Medicine , Nashville , TN , USA and.
authors.forename: J Scott
authors.initials: JS
authors.lastname: Daniels
mesh_terms: D000081:Acetamides / Q000493:pharmacokinetics; D042931:Aldehyde Oxidase / Q000378:metabolism*; D000818:Animals; D005260:Female; D006146:Guanidines / Q000493:pharmacokinetics; D006147:Guanine / Q000031:analogs & derivatives / Q000378:metabolism / Q000493:pharmacokinetics; D006168:Guinea Pigs; D006801:Humans; D008099:Liver / Q000187:drug effects* / Q000378:metabolism*; D008252:Macaca fascicularis; D008253:Macaca mulatta; D008297:Male; D051379:Mice; D010599:Pharmacokinetics; D011720:Pyrazoles / Q000493:pharmacokinetics; D011724:Pyridazines / Q000493:pharmacokinetics; D011743:Pyrimidines / Q000493:pharmacokinetics; D017207:Rats, Sprague-Dawley; D013045:Species Specificity; D013552:Swine; D013556:Swine, Miniature; D014230:Triazoles / Q000493:pharmacokinetics
chemical_list: C547925:6-(6-(1-methyl-1H-pyrazol-4-yl)-(1,2,4)triazolo(4,3-b)pyridazin-3-ylsulfanyl)quinoline; D000081:Acetamides; D006146:Guanidines; D011720:Pyrazoles; D011724:Pyridazines; D011743:Pyrimidines; D014230:Triazoles; C064976:O(6)-benzylguanine; D006147:Guanine; C424422:zoniporide; D042931:Aldehyde Oxidase; C085665:zaleplon
keywords: Aldehyde oxidase; S9; clearance; drug metabolism; molybdenum hydroxylase; noncytochrome P450; pharmacokinetics; species differences