3D-printed EVA-based patches manufactured by direct powder extrusion for personalized transdermal therapies

3D Printing Direct Powder Extrusion in the Production of Drug Delivery Systems: State of the Art and Future Perspectives

“…The 3D Cultures (Philadelphia, PA, USA) have also developed a single-screw DPE 3D printer consisting of a hopper, a single-screw extruder, and a 1 mm nozzle. This 3D printer was used to develop sustained-release tablets with square geometries and transdermal patches [ 32 , 33 ].…”

“…For the amorphous polymers, the minimum extrusion temperature was between 50 and 100 °C above their glass transition temperature. Nevertheless, higher temperatures were used for the crystalline polymers EVA 4030AC and EVA1821A, which had to be printed at 30 °C and 80 °C above their melting points, respectively, to lower the viscosity and facilitate the extrusion process [ 32 ].…”

“…With respect to the platform temperature, in the majority of the reviewed studies, the platform is heated. It has been observed that the heated bed increases the adhesion between the platform and the structure that is being printed [ 32 , 40 ]. The range of temperatures used in the different studies is wide, varying from 25 °C to 80 °C.…”

“…Other routes of administration, such as the transdermal route, have also been targeted for the preparation of dosage forms by DPE. Transdermal patches based on EVA 4030AC and EVA 1821A loaded with ibuprofen and diclofenac sodium (30% w / w theoretical content), respectively, were developed by DPE ( Figure 4 e) [ 32 ]. Increasing the VA content decreases the flexibility, stress-crack resistance, toughness, and melting point of the polymer.…”

“…In relation to the materials employed in the different formulations, only in a few studies the direct extrusion of a binary mixture of drug and polymer (HPC, EVA, PCL, and PHB) is possible [ 19 , 20 , 32 , 33 , 37 ], but in most cases, the use of auxiliary excipients is needed (see Table 2 ).…”