Articles
RSSImproved Curing Of EUDRAGIT® RL/RS 30 D Film Coatings By Controlled In-Process Curing In The Fluid Bed
January 15, 2009
•Poster: Improved Curing Of EUDRAGIT® RL/RS 30 D Film Coatings By Controlled In-Process Curing In The Fluid Bed
By Evonik Röhm GmbH
Aqueous EUDRAGIT® dispersions contain latex particles of around 100 nm diameter. These latex particles must coalesce to enable film formation. Coalescence is a precondition for the functionality of the fi lm coating and for a stable formulation. Depending upon polymer and formulation characteristics, an additional curing step might be required to complete latex coalescence. The time frame required for complete coalescence is infl uenced by the fi lm-forming behavior (MFT) of the polymer and the post-curing conditions (temperature, humidity).
Among the different EUDRAGIT® polymers, EUDRAGIT® RL and EUDRAGIT® RS types require the longest curing time. Conventionally, they are cured by post-drying for 24 h at 40 °C in an airfl ow oven. The aim of this study was to determine the limiting process parameters for an EUDRAGIT® RL/RS fi lm coating in order to obtain complete coalescence of the latex particles and stable release profi les according to ICH guidelines, using theophylline granules as a model.
The applied basic formulation contained EUDRAGIT® RL/RS 30 D (1:9) as the functional sustainedrelease fi lm former, Syloid 244 FP as the glidant, calculated on polymer dry substance, and triethyl citrate (TEC) as the plasticizer, calculated on polymer dry substance. The solids content of the formulation was calculated as 20 %. The polymer applied was 10 %.
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