Microfluidic Production of Biodegradable Microcapsules for Sustained Release of Hydrophilic Actives

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2017-08, Vol.13 (29), p.n/a
• Main Authors: Lee, Tae Yong, Ku, Minhee, Kim, Bomi, Lee, Sangmin, Yang, Jaemoon, Kim, Shin‐Hyun
• Format: Article
• Language: English
• Subjects: Biocompatibility; Biodegradability; biodegradable; Consolidation; encapsulation; Glucose; Glycolic acid; Membranes; Mice; microcapsules; Microencapsulation; microfluidics; Nanotechnology; Osmosis; Surgical implants; Sustained release
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201700646

Biodegradable microcapsules with a large aqueous lumen and ultrathin membrane are microfluidically designed for sustained release of hydrophilic bioactives using water‐in‐oil‐in‐water double‐emulsion drops as a template. As a shell phase, an organic solution of poly(lactic‐co‐glycolic acid) is used, which is consolidated to form a biodegradable membrane. The encapsulants stored in the lumen are released over a long period of time as the membranes degrade. The period can be controlled in a range of —three to five months at neutral pH condition by adjusting membrane thickness, providing highly sustained release and potentially enabling the programed release of multiple drugs. At acidic or basic condition, the degradation is accelerated, leading to the release in the period of approximately two months. As the membrane is semipermeable, the microcapsules respond to the osmotic pressure difference across the membrane. The microcapsules are inflated in hypotonic condition and deflated in hypertonic condition. Both conditions cause cracks on the membrane, resulting in the fast release of encapsulants in a day. The microcapsules implanted in mice also show sustained release, despite the period is decreased to a month. It is believed that the microcapsules are promising for the in vivo sustained release of drugs for high and long‐term efficacy. Biodegradable microcapsules are microfluidically designed to possess a large aqueous lumen and ultrathin membrane for a highly sustained release of hydrophilic bioactives. The period of release can be controlled in a range of several months at neutral pH condition by adjusting membrane thickness. The influence of pH and osmotic conditions on the release behavior is systematically studied for in vivo usages.