Which component in film coating provides flexibility?

The component that provides flexibility in film coating is the plasticizer. Plasticizers are added to coatings to enhance their flexibility, making them less brittle and more adaptable to mechanical stress. This is crucial in pharmaceutical applications because a flexible coating can better accommodate the expansion and contraction of the dosage form during handling and transportation without cracking or peeling.

By lowering the glass transition temperature of the film, plasticizers increase the mobility of the polymer chains within the coating. As a result, films containing plasticizers can maintain their integrity and perform optimally, even under various environmental conditions. This characteristic is particularly important in the context of oral dosage forms, where the coating must remain intact until the pharmaceutical compound is delivered to the appropriate site in the gastrointestinal tract.

Other components like binders serve to adhere the coating to the substrate but do not inherently provide flexibility. Diluents are typically used to increase the volume or bulk of the formulation, while stabilizers help maintain the stability of the formulation over time but do not contribute to flexibility in the same way that plasticizers do.