Modulating sustained drug release from nanocellulose hydrogel by adjusting the inner geometry of implantable capsules

Nanocellulose hydrogel has been shown to be an excellent platform for drug delivery and it has been lately studied as an injectable drug carrier. 3D printing is an effective method for fast prototyping of pharmaceutical devices with unique shape and cavities enabling new types of controlled release. In this study, we combined the versatility of 3D printing capsules with controlled geometry and the drug release properties of nanocellulose hydrogel to accurately modulate its drug release properties. We first manufactured non-active capsules via 3D printing from biocompatible poly(lactic acid) (PLA) that limit the direction of drug diffusion. As a novel method, the capsules were filled with a drug dispersion composed of model compounds and anionic cellulose nanofiber (CNF) hydrogel. The main benefit of this device is that the release of any CNF-compatible drug can be modulated simply by modulating the inner geometry of the PLA capsule. In the study we optimized the size and shape of the capsules inner cavity and performed drug release tests with common beta blockers metoprolol and nadolol as the model compounds. The results demonstrate that the sustained release profiles provided by the CNF matrix can be accurately modulated via adjusting the geometry of the 3D printed PLA capsule, resulting in adjustable sustained release for the model compounds.