Recent Advancements in Using Polymers for Intestinal Mucoadhesion and Mucopenetration.

Oral administration of actives is the most desired form of delivery, but the formulations need to overcome a variety of barriers including the intestinal mucus. This feature article summarizes the developments from the past 2-3 years in this context focusing on polymer-based formulations. The progress in assembling mucopenetrating nanoparticles is outlined considering coatings using noninteracting polymers as well as virus-like particles and charge-shifting particles. Next, polymers and their modification to enhance mucoadhesion are discussed, followed by providing examples of double-encapsulation systems that aim to combine mucopenetration with mucoadhesion in the same formulation. Finally, a short outlook is provided highlighting a few of the most pressing challenges to address.