Oral Thin Films: Formulation Strategies, Evaluation and Emerging Applications

Oral thin films (OTFs) are soft polymeric dosage forms which are to be administered on the tongue or against the oral mucosa. They can disintegrate quickly to deliver an active pharmaceutical ingredient (API) or they may stay in contact with the mucosa to facilitate local or transmucosal delivery or absorption. Their size, ease of transport and ease of administration without water may be beneficial to individuals who have difficulty swallowing traditional solid dosage forms. The properties of physicochemical property of API, polymer/excipient compatibility, film thickness, moisture content, mechanical strength, disintegration/residence time, drug release and packaging are the criteria that govern the performance of an OTF. Despite the many rapid developments in the polymer and composite industry in recent years, solvent casting is still one of the most widely used methods for developing/d manufacturing. Alternatives for selected materials and product targets are the hot-melt extrusion and electrospinning/printing processes. There are limitations to each method: Solvent casting can be tricky because drying and solvent residue can be problematic; some printing methods expose materials to heat, and electrospinning may require solvents and special equipment. Therefore, the method for evaluating quality must be established on a product-specific basis, as opposed to the use of a single disintegration result. This review aims to discuss the classification of OTFs, excipients, manufacturing processes, quality controls, therapeutic uses, marketed examples and novel technologies. Additionally, it also differentiates between rapidly disintegrating films and mucoadhesive buccal films due to their non-interchangeable performance targets. Characterization needs include harmonization, scale up, moisture protection, palatability, and reproducible scaling of dose distribution and proof of in-vitro/in-vivo correlation. The review is a draft of a review based on published pharmaceutical literature and should be considered a starting point for further searches in the database, reference checking and adaptation to the target journal.