Three-Dimensional Printing of Drug-Eluting Implants: Preparation of an Antimicrobial Polylactide Feedstock Material

The aim of the present work was to investigate the potential of three-dimensional (3D) printing as a manufacturing method for

products intended for personalized treatments by exploring the production of novel polylactide-based feedstock materials for 3D printing

purposes. Nitrofurantoin (NF) and hydroxyapatite (HA) were successfully mixed and extruded with up to 30% drug load with and without

addition of 5% HA in polylactide strands, which were subsequently 3D-printed into model disc geometries (10 × 2 mm). X-ray powder

diffraction analysis showed that NF maintained its anhydrate solid form during the processing. Release of NF from the disks was dependent

on the drug loading in a concentration-dependent manner as a higher level of released drug was observed from disks with higher drug

loads. Disks with 30% drug loading were able to prevent surface-associated and planktonic growth of Staphylococcus aureus over a period

of 7 days. At 10% drug loading, the disks did not inhibit planktonic growth, but still inhibited surface-associated growth. Elemental analysis

indicated the presence of microdomains of solid drug supporting the observed slow and partial drug release. This work demonstrates the

potential of custom-made, drug-loaded feedstock materials for 3D printing of pharmaceutical products for controlled release.