Film Coating of Tablets
This chapter provides an introduction to film coating—the formulation, application and evaluation of pharmaceutical film coatings. A well-coated tablet begins with a well-made core and, while tablet formulation is covered elsewhere in this volume, some key aspects of tablet cores as they pertain to coating are revisited here. The key formulation components of a film coat—the polymer, plasticiser, colourant and vehicle—are discussed, including the rationale for their use and approximate levels to be included within a formulation. The process for applying a film coat is at least as important to the quality of the finished product as the formulation of the coating and so significant aspects of the process and its control are covered. The chapter concludes with a description of the various techniques used to evaluate film coatings in development and manufacture.