Study of triethyl citrate migration from coating polymers to tablet cores.

Migration of plasticizers from film coating polymers towards the core and to the storage medium could result in serious changes in the mechanical properties and permeability of coatings thus greatly influencing rate and extent of drug release. The purpose of the present study was to follow the migration of water soluble triethyl citrate applied as a plasticizer in Acryl-Eze coating by Gas Chromatography/Mass Spectrometry (GC/MS). 20%w/w Acryl-Eze dispersions containing triethyl citrate of different concentrations were prepared. Placebo tablets were compressed and coated with the prepared dispersions. The coated tablets were stored under different relative humidity conditions for different time intervals. Considerable migration of triethyl citrate towards the tablet cores was found. The extent of the triethyl citrate migration was influenced by the relative humidity of the storage medium.