Current Advances of Hollow Capsules as Controlled Drug Delivery Systems

Abstract

Abstract Polymeric hollow capsules have attracted increasing interest for the development of controlled drug delivery systems due to their capacities to load high amount of drugs and be able to finely tune the drug release profile. Various methods and strategies for capsule preparation and drug loading have been developed over time. Besides that, the controlled drug release from hollow capsules upon external and internal triggers is of great interest and has been a research focus in this area. This article aims to give the most recent progress review on hollow capsule based controlled drug delivery systems with a highlight on strategies being used for drug loading and stimuli‐release. In detail, the fabrication of hollow capsules using template‐assisted or template‐free methods will be introduced first. This will be followed by current strategies for pre‐loading and post‐loading of therapeutic agents into capsules. The article will then be particularly focused on discussing diverse drug‐release systems corresponding to various stimuli conditions including temperature, pH, ultrasound, light irradiation and enzyme degradation.