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Journal of Applied Polymer Science
Volume 91, Issue 4 , Pages 2186 - 2194

Published Online: 8 Dec 2003

Poly(dimethylsiloxane) coatings for controlled drug release. II.
Mechanism of the crosslinking reaction in emulsion
Zongming Gao 1, Julia Schulze Nahrup 2, James E. Mark 1 *, Adel Sakr 2
1Department of Chemistry and the Polymer Research Center, University of
Cincinnati, Cincinnati, Ohio 45221
2Industrial Pharmacy Program, The College of Pharmacy, University of
Cincinnati, Cincinnati, Ohio 45267
email: James E. Mark (markje@email.uc.edu)

*Correspondence to James E. Mark, Department of Chemistry and the
Polymer Research Center, University of Cincinnati, Cincinnati, Ohio
45221

Funded by:
National Science Foundation; Grant Number: DMR-00-75198, DMR-0314760

Keywords
polysiloxanes • silicones • FTIR • crosslinking • coatings

Abstract
Earlier work focused on the crosslinking of hydroxyl-terminated
poly(dimethylsiloxane) (PDMS) particles in a stable latex suitable for
spraying onto drug tablets, and established the conditions for
eliminating the usual toxic catalysts that would be unacceptable in such
pharmaceutical coating materials. Use of these coatings for controlling
the rate of release of a drug, however, requires a better understanding
of their properties and thus clarification of the mechanism through
which the crosslinking occurs. The present study approaches this goal by
do***enting the effects of anionic, cationic, and nonionic surfactants
at various concentrations, and in acidic, neutral, or basic media. FTIR
spectroscopy was used to monitor the transportation of crosslinker from
the water phase into the hydrophobic PDMS phase. The results suggest a
possible mechanism for the crosslinking in sufficient detail to be used
to optimize the coatings for drug-release applications. © 2003 Wiley
Periodicals, Inc. J Appl Polym Sci 91: 2186-2194, 2004
Received: 17 March 2003; Accepted: 17 June 2003

Digital Object Identifier (DOI)

http://www3.interscience.wiley.com/cgi-bin/abstract/106570292/ABSTRACT