Dapivirine-releasing vaginal rings produced by plastic freeforming additive manufacturing

Here we report the first use of an additive manufacturing (AM) technique based on high pressure material jetting of molten thermoplastic for the fabrication of dapivirine (DPV) loaded vaginal rings (VRs). The VRs are compared to those produced conventionally using injection molding (IM). VRs (outer diameter 54.0 mm, cross-sectional diameter 4.0 mm) were manufactured by either injection molding or Arburg Plastic Freeforming (APF) - a proprietary droplet deposition modelling (DDM) process, using medical grade thermoplastic polyurethanes (TPUs) loaded with 10% w/w DPV. This unique DDM process was used to produce rings of 100, 50 and 10% matrix infill density. DDM printed VRs with 10% density (57-62 mg drug load) exhibited up to seven-fold increase in DPV release compared to injection molded rings containing 190-194 mg DPV. This work has shown that DDM using the APF technique can be used to manufacture drug delivery devices of varying geometries, densities and surface areas to give precise levels of control over the drug release kinetics. This work presents a new opportunity to increase the release of poorly water-soluble compounds or to achieve desired dosing levels using lower drug loadings than those required using conventional thermoplastic processing techniques.