Dynamic surface tension studies of hydroxypropylmethylcellulose film-coating solutions

Machiste, E.O. and Buckton, G. (1996) Dynamic surface tension studies of hydroxypropylmethylcellulose film-coating solutions. International Journal of Pharmaceutics, 145 (1-2). pp. 197-201. 10.1016/S0378-5173(96)04769-2.

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DOI: 10.1016/S0378-5173(96)04769-2

Abstract

Film coating of pharmaceuticals involves interfacial interactions based on adhesion and spreading of the polymer over the substrate surface. The surface tension of the polymer solution will have a major influence on these interfacial events. It is known that solutions of macromolecules exhibit surface ageing; however, data are not available concerning the dynamic surface tension (DST) of such systems in the first few seconds of surface formation. In this study, the DST of hydroxypropylmethylcellulose (HPMC) has been measured using a maximum bubble pressure method. It was found that, at all concentrations, the DST was higher than the equilibrium surface tension, but that at concentrations above 6% (w/w) this difference was much greater. This can be related to difficulties in film coating which can occur with more concentrated solutions. It was shown that additions of additives, such as poly(ethylene) glycol or lactose, had a detrimental impact on DST for the high-concentration solutions only. These data provide an improved understanding of the film coating process and give a route by which film-coating formulations may be optimised.

Item Type:Article
Uncontrolled Keywords:Film coating; Dynamic surface tension; Equilibrium surface tension; Hydroxypropylmethylcellulose
Departments, units and centres:Department of Pharmaceutics > Department of Pharmaceutics
ID Code:3254
Journal or Publication Title:International Journal of Pharmaceutics
Deposited By:Library Staff
Deposited On:18 May 2012 10:33
Last Modified:18 May 2012 10:33

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