title: Structural features determining the intestinal epithelial permeability and efflux of novel HIV-1 protease inhibitors.
abstract: The primary aim of this study was to identify structural features that alter the intestinal epithelial permeability and efflux in a series of novel HIV-1 protease inhibitors (PIs). Eleven PIs were selected containing a tertiary alcohol in a transition-state mimicking scaffold, in which two substituents (R(1) and R(2) ) were varied systematically. Indinavir was selected as a reference compound. The apical-to-basolateral permeability was investigated in 2/4/A1 and Caco-2 monolayers. In addition, the basolateral-to-apical permeability was investigated in the Caco-2 monolayers and the efflux ratios were calculated. The absence of active drug transport processes in 2/4/A1 cells allowed identification and modeling of structural elements affecting the passive permeability. For instance, small aromatic R(1) substituents and a small (bromo-) R(2) substituent were associated with a high passive permeability. Efflux studies in Caco-2 cells indicated that amide-substituted neutral hydrophobic amino acids, such as valine and leucine, in the R(1) position, reduced the apical-to-basolateral transport and enhanced the efflux. We conclude that our investigation revealed structural features that alter the intestinal epithelial permeability and efflux in the series of PIs and hope that these results can contribute to the synthesis of PIs with improved permeability and limited efflux properties.
authors.affiliation: Department of Pharmacy, Uppsala University, SE-751 23 Uppsala, Sweden.
authors.forename: Lucia
authors.initials: L
authors.lastname: Lazorova
authors.forename: Ina
authors.initials: I
authors.lastname: Hubatsch
authors.forename: Jenny K
authors.initials: JK
authors.lastname: Ekegren
authors.forename: Johan
authors.initials: J
authors.lastname: Gising
authors.forename: Daisuke
authors.initials: D
authors.lastname: Nakai
authors.forename: Noha M
authors.initials: NM
authors.lastname: Zaki
authors.forename: Christel A S
authors.initials: CA
authors.lastname: Bergström
authors.forename: Ulf
authors.initials: U
authors.lastname: Norinder
authors.forename: Mats
authors.initials: M
authors.lastname: Larhed
authors.forename: Per
authors.initials: P
authors.lastname: Artursson
mesh_terms: D018938:Caco-2 Cells; D017320:HIV Protease Inhibitors / Q000493:pharmacokinetics*; D015497:HIV-1; D006801:Humans; D007413:Intestinal Mucosa / Q000502:physiology*; D010539:Permeability
chemical_list: D017320:HIV Protease Inhibitors