Density Mediated Drug Release From Dapivirine Vaginal Rings Produced by Additive Manufacturing

Robert Malcolm, Nicole Welsh, Clare F. McCoy, Diarmaid Murphy, Brid Devlin, Peter Boyd

Research output: Contribution to conferencePosterpeer-review

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Background: Droplet deposition modelling (DDM) is a form of 3D printing that fuses droplets of molten polymer to create each layer, providing exquisite levels of control over an object‘s design and morphology. Such manipulation allows properties including density, geometry and surface area to be manipulated in ways that have been unthinkable using conventional thermoplastic processing techniques. Here we utilise the DDM process and compare this to injection moulding to produce dapivirine (DPV) loaded vaginal rings using a pharmaceutically relevant, life science grade thermoplastic polyurethane.

Methods: Vaginal rings (54.0 mm outer diameter, 4.0 mm cross sectional diameter) were fabricated by injection molding or Arburg Plastic Freeforming - a proprietary DDM process, using a hydrophobic TPU loaded with 10% w/w dapivirine. Using the DDM process, rings of 100, 50 and 10% matrix density were produced. Rings were evaluated for in vitro drug release over 29 days in an aqueous release media and assessed for thermal characteristics.

Results: Daily DPV release from all ring designs ranged between 387 - 8666 μg (Day 1) and 193 - 992 μg on Day 29. DDM printed VRs with 10% infill density (68 mg DPV load) exhibited a seven fold increase in DPV release rate compared to injection molded rings containing 190 mg DPV. For DDM printed rings, there was very significant correlation between decreasing ring density and increasing DPV release rate as a percentage of total drug loading. Thermal analysis showed that the DPV melt endotherm was absent from TPU + 10% w/w DPV, suggesting that DPV was fully solubilised within the TPU at the experimental conditions.

Conclusions: DDM printing on an Arburg Freeformer has been shown to create vaginal rings with a range of densities and has provided a new potential to either increase the release rate of poorly water soluble compounds or reduce the loading required to maintain a desired release rate.
Original languageEnglish
Publication statusPublished - 25 Oct 2018
EventHIV Research for Prevention 2018 - Madrid Marriott Auditorium Hotel, Madrid, Spain
Duration: 21 Oct 201825 Oct 2018


ConferenceHIV Research for Prevention 2018
Abbreviated titleHIVR4P 2018
Internet address


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