Controlled release from a composite silicone/hydrogel membrane

ASAIO J. 2000 Jul-Aug;46(4):431-4. doi: 10.1097/00002480-200007000-00012.

Abstract

To enhance the drug uptake and release capacity of silicone rubber (SR), N-isopropylacrylamide (NIPA) hydrogel particles have been incorporated into a SR membrane. The NIPA particles were thoroughly blended with uncured SR with a certain ratio at room temperature. The mixture was then cast in a Petri dish to 1 mm thickness and cured 10 hours at 90 degrees C. The SR/NIPA composite gel can absorb water approximately equal to its dry weight. Brilliant blue, used as a mock drug, was loaded into the composite gel. Drug release increased exponentially to a final value that is temperature dependent: low at T> =34 degrees C, and high at T< 34 degrees C. This finding is because the hydrophobicity of NIPA changes with temperature. Pulsed release in response to temperature switching between 20 and 39 degrees C has been achieved. Drug uptake and release capability strongly depends upon the structure of the composite gel. The optimal range of NIPA composition is between 75 and 87% by volume. In the cited range, the NIPA particles form an interconnected network that provides a channel for diffusion of drug solution. The SR/NIPA composite gel has promising attributes as a wound dressing and other uses.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acrylamides / chemistry
  • Adsorption
  • Drug Delivery Systems*
  • Hydrogels / chemistry*
  • Silicone Elastomers / chemistry*

Substances

  • Acrylamides
  • Hydrogels
  • Silicone Elastomers
  • N-isopropylacrylamide