Abstract
Aqueous polymeric dispersions are used for film coating of oral dosage forms (tablets, capsules, pellets) especially to control the drug release. Film formation on the surface of dosage forms is a complex process and involves several steps.
To optimize the coating process and drug dissolution as well as stability of the films, various excipients such as plasticizers, surfactants, antiadhesives and pigments are often added to polymeric dispersions. However, these additives are very often influencing the film properties and drug release.
This review article describes present knowledge on the field of aqueous polymeric dispersions and discusses main factors influencing the quality and proper function of film coatings. Attention is paid on one hand to dispersion additives and on the other hand to the conditions of the coating process, the importance of film drying and curing and the surfaces of coated substrates as well.