# Steering the Clinical Translation of Delivery Systems for Drugs and Health Products
## 3 Poster Presentations
### Biodegradable Nanoparticles for Ophthalmic Diseases
**Acknowledgments:** We want to thank Evonik Nutrition & Care GmbH from Evonik for the performance of SEM analyses and financing the e-tongue measurements and [PERSON] (in charge of the electronic microscopy service at the department of Entomology and Zoology section of DISSPA UNIBA) for his advices and contribution for SEM analysis as well. Coating of Retentive Drug Delivery Systems Based on Shape-Memory Poly(vinyl Alcohol) for Improved Release Performance  
[PERSON] *, [PERSON], [PERSON], [PERSON] and [PERSON]  
Sezione di Tecnologia e Legislazione Farmaceutiche \"[PERSON]\", Dipartimento di Scienze Farmaceutiche, Universita degli Studi di Milano, 20133 Milano, Italy  
* Correspondence: [EMAIL_ADDRESS]  
The water-induced shape-memory response of pharmaceutical-grade poly(vinyl alcohol) (PVA) of different molecular weight was recently demonstrated [76; 77]. Based on the ability of PVA-based items fabricated by fused deposition modeling (FDM) to take on a temporary shape and recover the original one upon contact with aqueous fluids at body temperature, 4D printing (i.e., 3D printing of objects that undergo changes in configuration upon exposure to an external non-mechanical _stimulus_) was proposed for the development of retentive systems intended for intragastric and intravesical drug delivery. Hot melt extrusion (HME) of rods to be wrapped around purposely developed templates was used for the rapid screening of different shapes potentially suitable for the site of retention. The temporary shape would allow the administration of the system, whereas the original bulky one would ensure its long-lasting residence in the target organ, by avoiding rapid emptying through the relevant opening. Following shape recovery, the system would ensure prolonged release of the conveyed drug and be safely eliminated by eroding/dissolving. Because the duration of release is a key issue for retentive drug delivery systems, the aim of the present work was to evaluate the application of permeable coatings based on insoluble film-forming polymers (e.g., Eudragit(r) Rl/Eudragit(r) RS) to PVA devices as a possible approach to modulate the release rate without affecting the relevant shape-memory behavior. Cylindrical rods of about 5 cm in length were prepared by HME (1.5 mm die, 215 \({}^{\circ}\)C, 20 rpm, 180 N\(\cdot\)cm) starting from a PVA formulation (Gohsen(tm) EG 48P plasticized with glycerol, 15% w/w on the dry polymer) containing 10% of a drug tracer. An ethanolic solution of Eudragit(r) RS and Eudragit(r) RL (3:1 w/w) containing 15% (w/w on the dry polymers) of triethyl citrate as the plasticizer was used as the coating formulation. A coating equipment was assembled, composed of: (i) a peristaltic pump (speed 10 rpm), (ii) a spray gun (nozzle 0.8 mm, atomizer 0.75 atm, pattern 1 atm) and (iii) an epicyclic planetary gearbox, in-house fabricated via FDM. The latter comprised 2 sets of gears, including the \"sun\" gear, directly moved by the rotor (2.3 rpm), and 4 satellite gears. The latter were in-built with the former and allowed positioning, along the gearbox height, of 4 samples at one time. The sun gear moved around its own axis only, while the satellites also rotated around the sun (i.e., revolution). In this way, the items to be coated were periodically exposed to the spray assembly, the rest of the rotation/revolution movement allowing for solvent evaporation. Through different process times, i.e., 4, 8 and 16 min, coated rods with increasing weight gain and coating thickness were obtained. After curing in a ventilated oven at 40 \({}^{\circ}\)C for 2 h, the samples were manually programmed to take on a temporary U-shape and quality of the film after this process was visually checked. The shape recovery behavior of the samples was not affected by the presence of the coating, at any thickness. On the other hand, the duration of release was enhanced as a function of the thickness of the applied film.