title: Mechanistic understanding of oral drug absorption enhancement of cromolyn sodium by an amino acid derivative.
abstract: OBJECTIVE
  Examine the oral absorption enhancement mechanism of cromolyn sodium by sodium N-[8-(2-hydroxybenzoyl) amino] caprylate (SNAC) by evaluating the effect of SNAC on cromolyn sodium lipophilicity and changes in Caco-2 cell membrane fluidity.
  
  
  METHODS
  Standard Shake-flask method was used to evaluate the effect of SNAC on the lipophilicity of cromolyn sodium. The measurements were carried out in three partitioning solvents with varying hydrogen-bonding properties. Steady state fluorescence emission anisotropy technique was used to evaluate the effect of SNAC with/without cromolyn sodium on Caco-2 cell membrane fluidity.
  
  
  RESULTS
  The lipophilicity measurements showed that SNAC had no influence on the lipophilicity of cromolyn sodium in the three partitioning solvent systems. The findings of the steady-state fluorescence anisotropy showed that SNAC increases the membrane fluidity of the Caco-2 cells in a concentration dependent manner. The increase in fluidity with SNAC was seen in the presence and absence of cromolyn sodium and the presence of cromolyn sodium did not augment the effect of SNAC on membrane fluidity.
  
  
  CONCLUSIONS
  The increase in membrane fluidity by SNAC plays a pivotal role in the permeation enhancement mechanism of cromolyn sodium. Therefore, the increase in permeation is a result of changing Caco-2 cell membrane fluidity resulting in change in membrane integrity and not due to an increase in the lipophilicity of cromolyn sodium through its interaction with SNAC.
authors.affiliation: School of Pharmacy, University of Wisconsin-Madison, Madison, WI 53705, USA, wgalani@wisc.edu
authors.forename: Adam W G
authors.initials: AW
authors.lastname: Alani
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Robinson
mesh_terms: D000284:Administration, Oral; D000465:Algorithms; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D018938:Caco-2 Cells; D002210:Caprylates / Q000494:pharmacology*; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002851:Chromatography, High Pressure Liquid; D004205:Cromolyn Sodium / Q000008:administration & dosage / Q000737:chemistry / Q000493:pharmacokinetics*; D005079:Excipients; D005454:Fluorescence Polarization; D006801:Humans; D006860:Hydrogen Bonding; D007408:Intestinal Absorption / Q000187:drug effects*; D008560:Membrane Fluidity / Q000187:drug effects
chemical_list: D018927:Anti-Asthmatic Agents; D002210:Caprylates; D005079:Excipients; C111140:N-(8-(2-hydroxybenzoyl)amino)caprylate; D004205:Cromolyn Sodium