A self-unfolding proximity enabling device for oral delivery of macromolecules

Fully Biodegradable Elastomer-Based Device for Oral Macromolecule Delivery

Oral devices, such as foil-type devices, show great potential for the delivery of poorly permeable macromolecules by enabling unidirectional release of the loaded pharmaceutical composition in close proximity to the epithelium in the small intestine or colon. However, one of the primary concerns associated with the use of foil-type devices so far has been the utilization of nonbiodegradable elastomers in the fabrication of the devices. Therefore, research into biodegradable substitute materials with similar characteristics enables drug delivery in a sustainable and environmentally friendly manner. In this study, a biodegradable elastomer, polyoctanediol citrate (POC), was synthesized via a one-pot reaction, with subsequent purification and microscale pattern replication via casting. The microstructure geometry was designed to enable fabrication of foil-type devices with the selected elastomer, which has a high intrinsic surface free energy. The final elastomer was demonstrated to have an elastic modulus ranging up to 2.2 ± 0.1 MPa, with strain at failure up to 110.1 ± 1.5%. Devices were loaded with acetaminophen and enterically coated, demonstrating 100% release at 2.5 h, following dissolution for 1 h in 0.1 M hydrochloric acid and 1.5 h in pH 6.8 phosphate-buffered saline. The elastomer demonstrated promising properties based on mechanical testing, surface free energy evaluation, and degradation studies.

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

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.

Untethered shape-changing devices in the gastrointestinal tract

INTRODUCTION

Advances in microfabrication, automation, and computer engineering seek to revolutionize small-scale devices and machines. Emerging trends in medicine point to smart devices that emulate the motility, biosensing abilities, and intelligence of cells and pathogens that inhabit the human body. Two important characteristics of smart medical devices are the capability to be deployed in small conduits, which necessitates being untethered, and the capacity to perform mechanized functions, which requires autonomous shape-changing.

AREAS COVERED

We motivate the need for untethered shape-changing devices in the gastrointestinal tract for drug delivery, diagnosis, and targeted treatment. We survey existing structures and devices designed and utilized across length scales from the macro to the sub-millimeter. These devices range from triggerable pre-stressed thin film microgrippers and spring-loaded devices to shape-memory and differentially swelling structures.

EXPERT OPINION

Recent studies demonstrate that when fully enabled, tether-free and shape-changing devices, especially at sub-mm scales, could significantly advance the diagnosis and treatment of GI diseases ranging from cancer and inflammatory bowel disease (IBD) to irritable bowel syndrome (IBS) by improving treatment efficacy, reducing costs, and increasing medication compliance. We discuss the challenges and possibilities associated with ensuring safe, reliable, and autonomous operation of these smart devices.