Spatially resolved solvent interaction with glassy HPMC polymers studied by magnetic resonance microscopy.
Magnetic resonance microscopy was used to study the interaction of an alkaline water solvent (pH=12) with hydroxypropylmethyl cellulose (HPMC) matrices with different molecular masses Mw=12,000, 86,000, and 120,000. The polymers in the form of cylinders were hydrated at 37 degrees C and monitored at equal time intervals with a 300MHz Bruker AVANCE. The spatially resolved spin-spin relaxations times T2 and diffusion coefficients D of the solvent molecules within the gel layer of HPMC samples, along with changes in the dimension of the glass core of the polymers were determined as a function of hydration times. The experimental data allows us to characterize the diffusion mechanism as being Fickian and to determine the mean diffusivity values D of the solvent molecules for each voxel within the gel of the studied polymers. The influence of the molecular mass of the HPMC polymers on swelling properties has been shown.
Tritt-Goc
Jadwiga
J
Institute of Molecular Physics, Polish Academy of Sciences, M. Smoluchowskiego 17, 60-179 Poznań, Poland. jtg@ifmpan.poznan.pl
Kowalczuk
Joanna
J
D004058:Diffusion; D016503:Drug Delivery Systems; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008747:Methylcellulose / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*
D011108:Polymers; D012997:Solvents; D008747:Methylcellulose