Release Behavior of W/O/W-Type Microcapsule

Article Preview

Abstract:

We have prepared W/O/W-type microcapsules with polyureaurethane wall membrane and aqueous core containing methylene blue by means of the double emulsification method and the effect of the rate of agitation at the twice emulsification on the release of methylene blue to dispersing methanol was examined. The release curve was expressed fairly well by the streched exponential form: where C(t) and Ceq are the concentrations of methylene blue in the dispersing methanol at time t and at the equilibrium state, respectively. The time constant τ increased and the exponent α decreased with increasing the rate of agitation at the second emulsification, whereas τ decreased and α was constant with increasing the rate of agitation at the first emulsification. These differences are discussed from a viewpoint of inhomogeneity of the microcapsule wall membrane.

You might also be interested in these eBooks

Info:

Periodical:

Pages:

55-60

Citation:

Online since:

December 2011

Export:

Price:

Permissions CCC:

Permissions PLS:

Сopyright:

© 2012 Trans Tech Publications Ltd. All Rights Reserved

Share:

Citation:

[1] A.L. Lewis, M.V. Gonzalez, A.W. Lloyd, B. Hall, Y. Tang, S.L. Willis, S.W. Leppard, L.C. Wolfenden, R.R. Palmer, P.W. Stratford: J Vasc Interv. Radiol. Vol. 17 (2006), p.335.

Google Scholar

[2] T. Kondo: J. Oleo Sci. Vol. 50 (2001) p.1.

Google Scholar

[3] Microencapsulation, Methods and Industrial Applications, Second Edition, edited by Simon Benita, Informa Healthcare (2006).

Google Scholar

[4] T. Sato, S. Shibako, T. Yamamoto, K. Ichikawa, T. Dobashi: J. Membrane Sci. Vol. 213 (2003), p.25.

Google Scholar

[5] T. Yamamoto, T. Dobashi, M. Kimura, and C.P. Chang: Colloids and Surf. B. Biointerfaces, Vol. 25, (2002), p.305.

Google Scholar

[6] C.P. Chang, T. Yamamoto, M. Kimura, T. Sato, K. Ichikawa and T. Dobashi: J. Controlled Release, Vol. 86 (2003), p.207.

Google Scholar