Vat photopolymerization (VP) is a family of 3D printing (3DP) technologies based on the photopolymerization of liquid light curable resins. VP 3D printed drug delivery systems (DDSs) have gained increasing popularity, offering multiple advantages over traditional DDS. Among them they offer the possibility to manufacture 3D devices with customizable design and intricate structure, and centred to the patient needs, facilitating the personalized medication. This chapter describes the VP techniques used for drug delivery applications, their advantages and limitations, and an overview of the DDS manufactured with VP 3DP technology.

New materials and manufacturing techniques are emerging with potential to address the challenges associated with the manufacture of pharmaceutical systems that will teach new tricks to old drugs. 3D printing (3DP) is a technique that can used for the manufacturing of dosage forms, and especially targeting paediatric and geriatric formulations, as permits the fabrication of high degrees of complexity with great reproducibility, in a fast and cost-effective fashion, and offers a new paradigm for the direct manufacture of personalised dosage forms. The book is covering the basics behind each additive manufacturing (AM) method, current applications in pharmaceutics for each 3DP method, and case studies (examples) from a teaching perspective, targeting undergraduate (UG) and postgraduate (PG) students. A unique to this book is the integration of studies based upon the use of different AM technologies, which designed to reinforce importance printing parameters and material considerations. The book includes case studies or multiple-choice questions (MCQs), which allow application of the content in a flipped-classroom.

In this study, liposomes enclosing eugenol were prepared using microfluidics. Two lipids—1,2-dimyristoyl-sn-glycero-3-phosphocholine, 18:0 (DSPC) and 2-dimyristoyl-sn-glycero-3-phosphocholine, 14:0 (DMPC)—and microfluidic chips with serpentine and Y-shaped micromixing designs were used for the liposomal formulation. Minimum bactericidal concentration (MBC) values indicated that eugenol was more effective against Gram-negative than Gram-positive bacteria. Four different flow-rate ratios (FRR 2:1, 3:1, 4:1, 5:1) were explored. All liposomes’ encapsulation efficiency (EE) was determined: 94.34% for DSPC 3:1 and 78.63% for DMPC 5:1. The highest eugenol release of 99.86% was observed at pH 4, DMPC 3:1 (Y-shaped chip). Liposomes were physically stable at 4, 20 and 37 °C for 60 days as determined by their size, polydispersity index (PDI) and zeta potential (ZP). The most stable liposomes were observed at FRR 5:1 for DSPC. EE, stability, and eugenol release studies proved that the liposomal formulations produced can be used as delivery vehicles to increase food safety.

The production of solid lipid nanoparticles (SLNs) is challenging, especially when considering the incorporation of biologics. A novel in-house method of microfluidic production of biologic-encapsulated SLNs is proposed, using a variety of base materials for formulation to help overcome the barriers presented during manufacture and administration. Trypsin is used as a model drug for hydrophilic encapsulation whilst testosterone is employed as a positive non-biologic lipophilic control active pharmaceutical ingredient. Particle sizes obtained ranged from 160 to 320 nm, and a lead formulation has been identified from the combinations assayed, allowing for high encapsulation efficiencies (47–90%, respectively) of both the large hydrophilic and the small hydrophobic active pharmaceutical ingredients (APIs). Drug release profiles were analysed in vitro to provide useful insight into sustained kinetics, providing data towards future in vivo studies, which displayed a slow prolonged release for testosterone and a quicker burst release for trypsin. The study represents a large leap forward in the field of SLN production, especially in the field of difficult-to-encapsulate molecules, and the technique also benefits from being more environmentally sustainable due to the use of microfluidics. Graphical Abstract

Vat photopolymerisation (VP) three-dimensional printing (3DP) has attracted great attention in many different fields, such as electronics, pharmaceuticals, biomedical devices and tissue engineering. Due to the low availability of biocompatible photocurable resins, its application in the healthcare sector is still limited. In this work, we formulate photocurable resins based on urethane dimethacrylate (UDMA) combined with three different difunctional methacrylic diluents named ethylene glycol dimethacrylate (EGDMA), di(ethylene glycol) dimethacrylate (DEGDMA) or tri(ethylene glycol) dimethacrylate (TEGDMA). The resins were tested for viscosity, thermal behaviour and printability. After printing, the 3D printed specimens were measured with a digital calliper in order to investigate their accuracy to the digital model and tested with FT-IR, TGA and DSC. Their mechanical properties, contact angle, water sorption and biocompatibility were also evaluated. The photopolymerizable formulations investigated in this work achieved promising properties so as to be suitable for tissue engineering and other biomedical applications.