Development of Cracks on Delayed Release Film of Hygroscopic Cores: A Review of the Tablet and Coating Formulations, Coating Process and Storage Conditions.

Abstract

An Aqueous dispersion of methacrylic acid copolymer NF is extensively used for delayed release coating in the pharmaceutical industry. However, one of the concerns is the developments of cracks on the coating film of hygroscopic tablet. The cracks on the film develop during storage. The film formed using methacrylic acid copolymer NF dispersion is inherently brittle. Therefore, the film cracks during storage especially when exposed to elevated heat and humidity. In general, the film cracks due to the mechanical stress during the coating process or by stretching effects in tablets after the coating process. The important factors to maintain the integrity of the coating film are: formulation of the core tablet and its hardness, formulation of the coating dispersion and coating process parameters. Core tablet hardness, its relaxation property, water content and content of the insoluble components in the coating formulation, temperature and relative humidity (RH) of the inlet air influence the film quality and integrity. in this paper, the probable reasons for the development of crack on the film of the hygroscopic core are discussed with reference to the properties of the core tablet, coating formulation (e.g., polymer, plasticizer, and insoluble excipients) and the coating process parameters.