title: A comparison of drug-induced cardiotoxicity in rat embryos cultured in human serum or protein free media.
abstract: BACKGROUND
  Although much reproductive toxicology research is performed in live animals there is increasing use of in vitro techniques primarily to identify potential hazards with human exposure. As many in vitro studies are undertaken using protein free media, the standard protocol is to compare the effect concentration determined in vitro with the predicted therapeutic free plasma concentration in humans. The aim of the present study was to test this rationale by comparing the effect of a small number of therapeutic drugs on heart rate of rodent embryos cultured in human sera or protein free serum.
  
  
  METHODS
  Whole rat embryos were cultured in protein-free media or human serum to which drugs (amiodarone, citalopram, dofetilide, haloperidol, paroxetine, quetiapine, or trazodone) known to induce embryonic bradycardia were added. Embryonic heart rate was observed before and after addition of drugs.
  
  
  RESULTS
  Most of the tested drugs (5/7) caused a greater decrease in embryonic heart rate in human sera than predicted based on the protein binding of the drug.
  
  
  CONCLUSIONS
  The results suggest that there is less unbound drug in the protein free media and/or more unbound drug in the human sera than predicted. Variables such as saturated protein binding and pH cannot fully explain our results. Since the results did not validate the original rationale, reproductive toxicity results obtained using protein free in vitro techniques may not have the large safety factors predicted on the basis of protein binding.
authors.affiliation: Discipline of Biomedical Sciences, Sydney Medical School, University of Sydney, PO Box 170, Lidcombe, NSW 1825, Australia. Electronic address: Helen.ritchie@sydney.edu.au.
authors.forename: Helen E
authors.initials: HE
authors.lastname: Ritchie
authors.affiliation: Discipline of Anatomy and Histology, Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: Cecilie Haaland
authors.initials: CH
authors.lastname: Svensson
authors.affiliation: Drug Safety and Toxicology, Department of Pharmaceutical Biosciences, Uppsala University, Sweden.
authors.forename: Mats F
authors.initials: MF
authors.lastname: Nilsson
authors.affiliation: Discipline of Anatomy and Histology, Sydney Medical School, University of Sydney, Sydney, NSW 2006, Australia.
authors.forename: William S
authors.initials: WS
authors.lastname: Webster
mesh_terms: D000638:Amiodarone / Q000633:toxicity; D000818:Animals; D001919:Bradycardia / Q000139:chemically induced*; D015283:Citalopram / Q000633:toxicity; D016895:Culture Media, Serum-Free / Q000737:chemistry / Q000494:pharmacology*; D003987:Dibenzothiazepines / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D004622:Embryo, Mammalian / Q000187:drug effects* / Q000196:embryology; D006220:Haloperidol / Q000633:toxicity; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D017374:Paroxetine / Q000633:toxicity; D010627:Phenethylamines / Q000633:toxicity; D000069348:Quetiapine Fumarate; D051381:Rats; D017207:Rats, Sprague-Dawley; D044967:Serum / Q000737:chemistry*; D013449:Sulfonamides / Q000633:toxicity; D014196:Trazodone / Q000633:toxicity
chemical_list: D016895:Culture Media, Serum-Free; D003987:Dibenzothiazepines; D010627:Phenethylamines; D013449:Sulfonamides; D015283:Citalopram; D000069348:Quetiapine Fumarate; D017374:Paroxetine; D006220:Haloperidol; D000638:Amiodarone; C063533:dofetilide; D014196:Trazodone
keywords: Citalopram; Dofetilide; In vitro screens; Methods; Pharmaceuticals; Teratogenicity; Whole rat embryo culture amiodarone