A review: Gelatine as a bioadhesive material for medical and pharmaceutical applications

Bioadhesive polymers offer versatility to medical and pharmaceutical inventions. The incorporation of such materials to conventional dosage forms or medical devices may confer or improve the adhesivity of the bioadhesive systems, subsequently prolonging their residence time at the site of absorption or action and providing sustained release of actives with improved bioavailability and therapeutic outcomes. For decades, much focus has been put on scientific works to replace synthetic polymers with biopolymers with desirable functional properties. Gelatine has been considered one of the most promising biopolymers. Despite its biodegradability, biocompatibility and unique biological properties, gelatine exhibits poor mechanical and adhesive properties, limiting its end-use applications. The chemical modification and blending of gelatine with other biomaterials are strategies proposed to improve its bioadhesivity. Here we discuss the classical approaches involving a variety of polymer blends and composite systems containing gelatine, and gelatine modifications via thiolation, methacrylation, catechol conjugation, amination and other newly devised strategies. We highlight several of the latest studies on these strategies and their relevant findings.