title: Interaction Study of an Amorphous Solid Dispersion of Cyclosporin A in Poly-Alpha-Cyclodextrin with Model Membranes by (1)H-, (2)H-, (31)P-NMR and Electron Spin Resonance.
abstract: The properties of an amorphous solid dispersion of cyclosporine A (ASD) prepared with the copolymer alpha cyclodextrin (POLYA) and cyclosporine A (CYSP) were investigated by (1)H-NMR in solution and its membrane interactions were studied by (1)H-NMR in small unilamellar vesicles and by (31)P (2)H NMR in phospholipidic dispersions of DMPC (dimyristoylphosphatidylcholine) in comparison with those of POLYA and CYSP alone. (1)H-NMR chemical shift variations showed that CYSP really interacts with POLYA, with possible adduct formation, dispersion in the solid matrix of the POLYA, and also complex formation. A coarse approach to the latter mechanism was tested using the continuous variations method, indicating an apparent 1 : 1 stoichiometry. Calculations gave an apparent association constant of log Ka = 4.5. A study of the interactions with phospholipidic dispersions of DMPC showed that only limited interactions occurred at the polar head group level ((31)P). Conversely, by comparison with the expected chain rigidification induced by CYSP, POLYA induced an increase in the fluidity of the layer while ASD formation led to these effects almost being overcome at 298 K. At higher temperature, while the effect of CYSP seems to vanish, a resulting global increase in chain fluidity was found in the presence of ASD.
authors.affiliation: IRBA, RNI-Biophysics Laboratory, 24, avenue des Maquis du Grésivaudan, BP 82, 38702 La Tronche Cedex, France.
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Debouzy
authors.affiliation: IRBA, RNI-Biophysics Laboratory, 24, avenue des Maquis du Grésivaudan, BP 82, 38702 La Tronche Cedex, France.
authors.forename: David
authors.identifier: 0000-0002-7051-3966
authors.initials: D
authors.lastname: Crouzier
authors.affiliation: IRBA, RNI-Biophysics Laboratory, 24, avenue des Maquis du Grésivaudan, BP 82, 38702 La Tronche Cedex, France.
authors.forename: Fréderic
authors.initials: F
authors.lastname: Bourbon
authors.affiliation: Galenic Pharmaceutical Laboratory, LAGEP UMR CNRS 5007, UFR Medicine and Pharmacy, 22 boulevard Gambetta, 76183 Rouen, France.
authors.forename: Malika
authors.initials: M
authors.lastname: Lahiani-Skiba
authors.affiliation: Galenic Pharmaceutical Laboratory, LAGEP UMR CNRS 5007, UFR Medicine and Pharmacy, 22 boulevard Gambetta, 76183 Rouen, France.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Skiba