title: Reply to "On the Effect of Common Excipients on the Oral Absorption of Class 3 Drugs".
abstract: We previously concluded that 12 common excipients need not be qualitatively the same and quantitatively very similar to reference for Biopharmaceutics Classification System-based biowaivers. This conclusion for regulatory relief is based upon a series of bioequivalence studies in humans involving cimetidine and acyclovir. Limitations were also discussed. We understand the major concern of García-Arieta et al. is that "results obtained by Vaithianathan et al. should not be extrapolated to other drugs." We understand that individuals conducting their own risk/benefit analysis may reach that conclusion, and we reply to the concerns of García-Arieta et al. We continue to conclude that the 12 common excipients need not be qualitatively the same nor quantitatively very similar to reference, but rather, simply be not more than the quantities studied in our manuscript for cimetidine and acyclovir, and potentially other class 3 drugs with similar properties.
authors.affiliation: Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201.
authors.forename: Soundarya
authors.initials: S
authors.lastname: Vaithianathan
authors.affiliation: Center for Drug Evaluation, Food and Drug Administration, Silver Spring, Maryland 20993.
authors.forename: Sam H
authors.initials: SH
authors.lastname: Haidar
authors.affiliation: Center for Drug Evaluation, Food and Drug Administration, Silver Spring, Maryland 20993.
authors.forename: Xinyuan
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Center for Drug Evaluation, Food and Drug Administration, Silver Spring, Maryland 20993.
authors.forename: Wenlei
authors.initials: W
authors.lastname: Jiang
authors.affiliation: Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201.
authors.forename: Christopher
authors.initials: C
authors.lastname: Avon
authors.affiliation: Department of Pharmacy Practice, Ferris State University, Grand Rapids, Michigan 49503.
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Dowling
authors.affiliation: Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201.
authors.forename: Changxing
authors.initials: C
authors.lastname: Shao
authors.affiliation: Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201.
authors.forename: Maureen
authors.initials: M
authors.lastname: Kane
authors.affiliation: Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201.
authors.forename: Stephen W
authors.initials: SW
authors.lastname: Hoag
authors.affiliation: Department of Gastroenterology and Hepatology, University of Maryland, Baltimore, Maryland 21201.
authors.forename: Mark H
authors.initials: MH
authors.lastname: Flasar
authors.affiliation: Department of Neurology, University of Maryland, Baltimore, Maryland 21201.
authors.forename: Tricia Y
authors.initials: TY
authors.lastname: Ting
authors.affiliation: Department of Pharmaceutical Sciences, University of Maryland, Baltimore, Maryland 21201. Electronic address: jpolli@rx.umaryland.edu.
authors.forename: James E
authors.initials: JE
authors.lastname: Polli
mesh_terms: D001702:Biopharmaceutics; D005079:Excipients; D006801:Humans; D010539:Permeability; D012995:Solubility; D013810:Therapeutic Equivalency
chemical_list: D005079:Excipients
keywords: acyclovir; bioequivalence; biopharmaceutics classification system; cimetidine; excipients; oral absorption; permeability