From Pharma-Grade Filaments to Capsular Delivery Systems

I believe that the future of healthcare may rely on personalized medicine. According to the FDA, this means “the tailoring of medical treatment to the individual characteristics, needs, and preferences of a patient during all stages of care, including prevention, diagnosis, treatment, and follow-up”. But today’s therapeutic approach is quite the opposite: drugs don’t adapt to patients; instead patients have to adapt to mass-produced medications with a fixed dosage and release performance. Our research team has been investigating innovative manufacturing technologies to develop custom drug delivery systems, and one area of interest for us is 3D printing.

For years, we have been looking at capsular devices that act as containers for different types of drugs and formulations, releasing their contents depending on the characteristics of the shell (in terms of composition, shape, wall thickness, presence of openings, slots and internal cavities). These capsules have been prepared by injection molding and, more recently, we decided to see if it was feasible also to use fused deposition modeling (FDM, see 3D Printing 101).

FDM is drawing considerable interest from the pharma industry. One use for FDM is rapid prototyping, which would enable companies to evaluate the design, materials and use of products before their final release. However, a drawback at the moment is that no pharmaceutical-grade filaments are commercially available.

To that end, we decided to develop a pharmaceutical filament that could be used by an existing FDM printing system to create a custom delivery system called the Chronocap, for oral pulsatile and colonic delivery, which we previously manufactured using injection molding. The material used for the filament was hydroxypropyl cellulose (HPC), a swellable/erodible pharma-grade polymer (1).

A commercial 3D printer was used to manufacture hollow bodies that could then be assembled into capsular devices. HPC filaments suitable for feeding the FDM equipment were manufactured using hot-melt extrusion. By introducing minor modifications in both the hardware and software of the printer, we successfully produced both capsule bodies and caps using our HPC filament. In vitro tests demonstrated that the 3D printed devices behaved as pulsatile-delivery containers, showing a satisfactory release performance (lag phase of about 70 min) comparable with that of analogous molded systems with the same composition.

It’s an early stage project but the results are exciting – as is the future.

Gazzaniga collaborated on this research with Alice Melocchi, Giulia Loreti, Alessandra Maroni and Lucia Zema (all from Università degli Studi di Milano, Italy) and with Federico Parietti (Massachusetts Institute of Technology, USA).