Self-diffusion and molecular mobility in PVA-based dissolution-controlled systems for drug delivery

Magn Reson Imaging. 1998 Jun-Jul;16(5-6):691-4. doi: 10.1016/s0730-725x(98)00021-6.

Abstract

Nuclear magnetic resonance (NMR) microscopy has been used to monitor the hydration of poly(vinyl alcohol) (PVA) samples of varying molecular weight. One-dimensional profiles weighted to predominantly show the variation of water concentration were acquired every 3 min during the first 30 min of hydration and subsequently at 1 and 2 h. Diffusion-weighted profiles obtained after 30 min and 1 and 2 h were used to calculate the spatial variation of the water self-diffusion coefficient. The resulting data provide supporting evidence for the hypothesis that phenomena such as reptation are important near the glassy/rubbery interface of polymers during dissolution, while the diffusion gradually changes to Zimm type near the rubbery/solvent interface.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Diffusion
  • Drug Delivery Systems*
  • Humans
  • Magnetic Resonance Spectroscopy*
  • Microscopy*
  • Molecular Weight
  • Polyvinyl Alcohol*
  • Tablets
  • Water

Substances

  • Tablets
  • Water
  • Polyvinyl Alcohol