title: Impact of oxcarbazepine sulfate metabolite on incurred sample reanalysis and quantification of oxcarbazepine.
abstract: BACKGROUND
  Recently, incurred sample reanalysis (ISR) has become a requirement in bioanalysis. The general guidance recommends investigating ISR failure to evaluate the suitability of an analytical method. In the case of acceptable ISR evaluation, there were no precise recommendations for further testing when sporadic values were obtained.
  
  
  RESULTS
  The ISR evaluation performed during a bioequivalence study for the anticonvulsant drug oxcarbazepine showed acceptable ISR results, but one particular chromatographic anomaly led to a thorough investigation. The finding of these tests showed that an oxcarbazepine phase II metabolite occasionally co-eluted with the drug and impacted oxcarbazepine's quantitation through in-source conversion.
  
  
  CONCLUSIONS
  This paper demonstrates the necessity of rigorous interpretation of ISR results and close monitoring of all subject sample results.
authors.affiliation: Algorithme Pharma Inc., 575 Armand Frappier, Laval, Quebec, Canada.
authors.forename: Catherine
authors.initials: C
authors.lastname: Dicaire
authors.forename: Eugénie-Raphaelle
authors.initials: ER
authors.lastname: Bérubé
authors.forename: Isabelle
authors.initials: I
authors.lastname: Dumont
authors.forename: Milton
authors.initials: M
authors.lastname: Furtado
authors.forename: Fabio
authors.initials: F
authors.lastname: Garofolo
mesh_terms: D000927:Anticonvulsants / Q000627:therapeutic use; D016477:Artifacts; D001711:Biotransformation; D002138:Calibration / Q000592:standards; D002220:Carbamazepine / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D002851:Chromatography, High Pressure Liquid; D017408:Guidelines as Topic; D006801:Humans; D013058:Mass Spectrometry; D000078330:Oxcarbazepine; D011786:Quality Control; D012015:Reference Standards; D015203:Reproducibility of Results; D012107:Research Design; D012640:Seizures / Q000097:blood / Q000188:drug therapy; D013431:Sulfates / Q000378:metabolism*; D013810:Therapeutic Equivalency; D054928:Validation Studies as Topic
chemical_list: D000927:Anticonvulsants; D013431:Sulfates; D002220:Carbamazepine; D000078330:Oxcarbazepine