Towards Elucidation of 3D Printed Drug Dissolution Mechanisms via NIR Mapping

In fifteen words or less, explain the significance of this contribution (Novel Aspect).: Application of mapping techniques to understand release mechanisms from 3D printed tablets.

Abstract Text: 3D printing of pharmaceuticals is an emerging field, which will have many exciting applications in the sphere of personalised medicine. 3D printed tablet designs allow access to different, novel geometries which would be otherwise inaccessible using traditional compaction methods. It has previously been demonstrated the release rate of dosages with the same formulation can be differentiated by the tablet geometry. The mechanics of drug release and water ingress will be different to compacted tablets due to the differences in structure and porosity.

In this work two model APIs (active pharmaceutical ingredients), Indomethacin and Caffeine were used to produce two separate blends with HPC (hydroxypropyl cellulose), a hydrophilic polymer. These blends were then used to produce two different geometries of 3D printed tablets, as well as a tablet formed by compaction, a more traditional route of manufacture.

The dissolution of these tablets was then examined using a conventional paddle method to determine the drug release profile of each tablet in 0.1M HCl. Then a custom flow cell was used in conjunction with Near Infrared (NIR) mapping to provide a series of global images of the radial dissolution of the tablets, as a function of time. These images gave spatially-resolved data which facilitated the tracking of water ingress, polymer swelling and drug release in real time, throughout the dissolution process. This data could be correlated to the conventional dissolution profile.

This work aims to improve our understanding of drug release mechanisms in 3D printed tablets, which do not follow the well-established models of release from compacted tablet hydrophilic polymer matrices.