title: Influence of vitamin E TPGS poly(ethylene glycol) chain length on apical efflux transporters in Caco-2 cell monolayers.
abstract: D-alpha-tocopheryl poly(ethylene glycol) 1000 succinate (TPGS 1000) is a widely used form of vitamin E. TPGS 1000 is comprised of a hydrophilic polar (water-soluble) head and a lipophilic (water-insoluble) alkyl tail. TPGS 1000 has been used as a solubilizer, an emulsifier and as a vehicle for lipid-based drug delivery formulations. Most recently, TPGS 1000 has been recognized as an effective oral absorption enhancer. An enhancing effect is consistent with a surfactant-induced inhibition of P-glycoprotein (P-gp), and perhaps other drug transporter proteins; however, the exact inhibition mechanism(s) remain unclear. Therefore, in an attempt to generate additional knowledge, we have synthesized and tested various TPGS analogs containing different PEG chain length (TPGS 200/238/400/600/1000/2000/3400/3500/4000/6000). These results demonstrate a relationship between TPGS PEG chain length and influence on rhodamine 123 (RHO) transport in Caco-2 monolayers, a relationship which may be illustrated using a Weibull distribution.
authors.affiliation: Department of Biopharmaceutics and Pharmaceutical Technology, Saarland University, 66123 Saarbruecken, Germany.
authors.forename: Eva-Maria
authors.initials: EM
authors.lastname: Collnot
authors.forename: Christiane
authors.initials: C
authors.lastname: Baldes
authors.forename: Michael F
authors.initials: MF
authors.lastname: Wempe
authors.forename: John
authors.initials: J
authors.lastname: Hyatt
authors.forename: Lisa
authors.initials: L
authors.lastname: Navarro
authors.forename: Kevin J
authors.initials: KJ
authors.lastname: Edgar
authors.forename: Ulrich Friedrich
authors.initials: UF
authors.lastname: Schaefer
authors.forename: Claus-Michael
authors.initials: CM
authors.lastname: Lehr
mesh_terms: D000704:Analysis of Variance; D001692:Biological Transport / Q000187:drug effects; D018938:Caco-2 Cells; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D015394:Molecular Structure; D011092:Polyethylene Glycols / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology; D021281:Quantitative Structure-Activity Relationship; D020112:Rhodamine 123 / Q000493:pharmacokinetics*; D014810:Vitamin E / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology
chemical_list: D014810:Vitamin E; D020112:Rhodamine 123; D011092:Polyethylene Glycols; C014225:tocophersolan