Flexible Coatings Facilitate pH-Targeted Drug Release via Self-Unfolding Foils: Applications for Oral Drug Delivery

Abstract

Ingestible self-configurable proximity-enabling devices have been developed as a non-invasive platform to improve the bioavailability of drug compounds via swellable or self-unfolding devices. Self-unfolding foils support unidirectional drug release in close proximity to the intestinal epithelium, the main drug absorption site following oral administration. The foils are loaded with a solid-state formulation containing the active pharmaceutical ingredient and then coated and rolled into enteric capsules. The coated lid must remain intact to ensure drug protection in the rolled state until targeted release in the small intestine after capsule disintegration. Despite promising results in previous studies, the deposition of an enteric top coating that remains intact after rolling is still challenging. In this study, we compare different mixtures of enteric polymers and a plasticizer, PEG 6000, as potential coating materials. We evaluate mechanical properties as well as drug protection and targeted release in gastric and intestinal media, respectively. Commercially available Eudragit® FL30D-55 appears to be the most suitable material due to its high strain at failure and integrity after capsule fitting. In vitro studies of coated foils in gastric and intestinal media confirm successful pH-triggered drug release. This indicates the potential advantage of the selected material in the development of self-unfolding foils for oral drug delivery.

Fully Biodegradable Elastomer-Based Device for Oral Macromolecule Delivery

“…FL30D-55 consists of a combination of an enteric and flexible coating, yielding a flexible film suitable for application to these devices. 22 Subsequently, 400 and 200 loops were selected to assess the impact of coating thickness on acetaminophen release profiles.…”

“…The coating formulation and procedure used have previously yielded coatings with thickness of 26.63 ± 0.77 μm when 400 loops of coating were applied denoted above as “thick”. FL30D-55 consists of a combination of an enteric and flexible coating, yielding a flexible film suitable for application to these devices . Subsequently, 400 and 200 loops were selected to assess the impact of coating thickness on acetaminophen release profiles.…”

“…The foils were weighed before and after API loading to ascertain the loaded mass. The coating formulation and application method used were adopted from Miliań-Guimeráet al 22 Eudragit FL30D-55 was diluted to 2-wt % in isopropyl alcohol (IPA) prior to lid deposition using ultrasonic spray coating. An ultrasonic spray coater (ExactaCoat system, Sono-Tek, Milton, NY, U.S.A.) equipped with a microbore-fitted 120 Hz Vortex nozzle was used.…”