(T1430-12-82) Personalized 3D Printing Earring Tap for Treating Affections Caused by Aesthetic Perforations

Purpose: 3D printing of medicines is one of the most trendy topics in pharmaceutical research today. This technology allows the production of innovative drug dosage forms, such as drug-delivery wearable devices. This work aimed to develop a 3D wearable drug-loaded earring tap to treat affections caused by aesthetic perforations. The treatment of such inflamed regions usually requires the removal of the earring or piercing, which leads to the closure of the perforation made to fit the adornment. In this sense, making the adornment itself a vehicle for drug treatment can eliminate this drawback.

Methods: The first phase of this study consisted of selecting the ideal combination of polymers to prepare filaments by hot-melt extrusion for use in FDM 3D printing. A simplex centroid mixture design using three polymers (soluplus^®, hydroxypropyl cellulose, and polyvinyl alcohol) was used for this purpose. A predictive model was constructed based on printability (fracture force), drug release (dissolution efficiency), and moisture absorption. In the second phase, optimized filament compositions were used to produce FDM 3D printed earring taps containing the anti-inflammatory drug naringenin. Next, samples were evaluated by physicochemical assays, including thermal, spectroscopic, diffractometric, morphological, and rheological studies. Finally, in vitro skin permeation studies were performed using Franz-type diffusion cells mounted with porcine's ear skin.

Results: Formulation optimization using a mixture design has proven essential in obtaining viable filaments for FDM 3D printing with adequate stability. i.e., minimum water uptake and fracture force enough to guarantee printability. Considering the obtained model, two filament compositions were selected for the study's second phase. One with the aim of accelerating the release of the drug through the rapid disintegration of the matrix, which had only PVA as a polymer in its composition (filament A), and another containing a mixture of the three polymers that act synergistically to slow down the dissolution of the drug (filament B). Both filaments demonstrated chemical compatibility, amorphous behavior by X-ray powder diffraction, and no evidence of stability loss according to thermal analysis. Scanning electron microscope images indicated the formation of crystal clusters on the surface of the printed devices of filament A (Figure 1). Rheological analysis reinforced the use of the polymer blend to improve printability, and both filaments were smoothly printed. In vitro drug permeation studies (Figure 2) showed that the filaments increased the drug recovered from the skin, regardless of the formulation, improving the drug recovered on the skin surface (filament A) and on the skin inner layers (filament B). Moreover, the control containing the free drug had a higher drug recovery in the receptor medium, which might enhance adverse effects giving rise to a possible transdermal absorption.

Conclusion: Patient-centred drug devices are the future of medicine since personalized therapeutic strategies can address individual patients' unique physiological needs, making treatment more effective. In this regard, using 3D printing drug-delivery wearable devices as a topical treatment for aesthetic perforations complication is a viable and innovative option. Notably, using predictive models based on statistical strategies such as the mixture design proved very useful in obtaining the most adequate filament composition, i.e., with printability, stability, and the desired drug release profile. Thus, the resulting systems have shown promise to produce 3D printed earring taps with the topical release of the anti-inflammatory naringenin.

Acknowledgements: The authors declare that they have no conflict of interest. The authors acknowledge the Federal District Research Support Foundation (FAP-DF, Brazil, grant n. 0019300000229/202121).

Figure 1. Scanning electron microscope images and optical microscopy photomicrographs of printed devices produced with filaments A and B. Blue circles indicate crystal clusters on the surface of filament B.

Figure 2. Naringenin (NAR) recovered from (A) stratum corneum, (B) remaining skin, (C) Receptor medium, and (D) all skin layers (n = 5) (*** p ≤ 0.001; **** p ≤ 0.0001).