title: Enclosed volume determination of concentrated dioctadecyldimethylammonium chloride (DODAC) vesicular dispersions by low-resolution proton NMR diffusometry and T2 relaxometry.
abstract: The enclosed volume of concentrated dioctadecyldimethylammonium chloride (DODAC) dispersions has been determined by means of low-resolution NMR pfg-diffusometry and T(2) relaxometry. The pfg-NMR diffusometry method is based on the different diffusion behaviors of water in the external and internal phases and as such does not require the addition of a tracer. On the other hand, T(2) relaxometry is based on the different relaxation behaviors of water fractions upon addition of manganese chloride as external (paramagnetic) probe. It was noticed that reliable results are found only for temperatures below the phase transition temperature of DODAC, when the exchange between the two water compartments can be neglected. At 5 °C, these two independent methods resulted in similar enclosed volume values, meaning that the results are reliable and reflect the real enclosed volume. In addition, the T(2) relaxometry method has been proven to be useful in the investigation of the DODAC membrane permeability.
authors.affiliation: Particle and Interfacial Technology Group, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Gent, Belgium. Paolo.Sabatino@UGent.be
authors.forename: Paolo
authors.initials: P
authors.lastname: Sabatino
authors.forename: Pieter
authors.initials: P
authors.lastname: Saveyn
authors.forename: José C
authors.initials: JC
authors.lastname: Martins
authors.forename: Paul
authors.initials: P
authors.lastname: Van der Meeren
mesh_terms: D002712:Chlorides; D004058:Diffusion; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D017895:Manganese Compounds; D008567:Membranes, Artificial; D010539:Permeability; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D013696:Temperature; D044366:Transition Temperature
chemical_list: D002712:Chlorides; D017895:Manganese Compounds; D008567:Membranes, Artificial; D000644:Quaternary Ammonium Compounds; C015831:dimethyldioctadecylammonium; C025340:manganese chloride