Novel polyester-based thermoplastic elastomers for 3D-printed long-acting drug delivery applications

To improve patient compliance and personalised drug delivery, long-acting drug delivery devices (LADDDs), such as implants and inserts, greatly benefit from a customisation in their shape through the emerging 3D-printing technology, since their production usually follows a one-size-fits-most approach. The use of 3D-printing for LADDDs, however, is mainly limited by the shortage of flawlessly 3D-printable, yet biocompatible materials.

Highlights

A novel 3D-printing excipient for long-acting drug delivery devices is introduced.

A mechanistic understanding of material requirements for 3D-printing is presented.

A novel progesterone immersion strategy for 3D-printed devices is developed.

The novel excipient shows comparable drug permeability to ethylene-vinyl acetate.

The present study tackles this issue by introducing a novel, non-biodegradable material, namely a polyester-based thermoplastic elastomer (TPC) – a multi-block copolymer containing alternating semi-crystalline polybutylene terephthalate hard segments and poly-ether-terephthalate amorphous soft segments. Next to a detailed description of the material’s 3D-printability by mechanical, rheological and thermal analyses, which was found to be superior to that of conventional polymers (ethylene-vinyl acetates (EVA)), this study establishes the fundamental understandings of the interactions between progesterone (P4) and TPC and drug-releasing properties of TPC for the first time.

P4-loaded LADDDs based on TPC, prepared via an elaborated solvent-immersion technique, enable the release of P4 at pharmacologically relevant rates, similar to those of marketed formulations based on EVA and silicones. Additionally, TPC demonstrated an exceptional 3D-printability for a wide selection of implant sizes and complex geometries.

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Article information: Ioannis Koutsamanis, Amrit Paudel, Carolina Patricia Alva Zúñiga, Laura Wiltschko, Martin Spoerk. Novel polyester-based thermoplastic elastomers for 3D-printed long-acting drug delivery applications, Journal of Controlled Release, Volume 335, 2021. https://doi.org/10.1016/j.jconrel.2021.05.030.