Understanding direct powder extrusion for fabrication of 3D printed personalised medicines: a case study for nifedipine minitablets

Fuse deposition modelling (FDM) has emerged as a novel technology to manufacture 3D printed medicines. However, it is a two step process as previous to the printing, the fabrication of filaments using a hot melt extruder with suitable properties for printing is required. This can be the rate-limiting step in its application into into clinical practice. Direct powder extrusion can overcome the difficulties encountered with fabrication of pharmaceutical quality filaments for FDM and in a single step a3D printed solid dosage forms can be engineered. We are demonstrating in this study that manufacturing of small weight (< 100 mg) solid dosage forms with high drug loading (25%) can be easilty manufactured by healthcare professionals to treat hypertension. 3D printed nifedipine minitablets containing 20 mg were manufactured by direct powder extrusion combining 15% polyethylene glycol 4000 Da, 40% hydroxypopyl cellulose, 19% hydroxy propyl methyl cellulose acetate succinate and 1% magnesium stearate. Fabricated 3D printed minitablets of small overall weight maintained their strength over prolonged time periods allowing for a controlled drug release for 24 h based on erosion. The release profile of the printed minitablets ismore suitable for hypertensive patients than immediate release tablets that can lead to a marked burst effect tirggering hypotension. The small size of the minitablet fits inside of a 0 size capsule what would allow to be combined with other minitablets for the treatment of complex diseases requiring polypharmacy within a single dosage form.