Additive Manufacturing and 3D Printing

A Comprehensive Overview of Additive Manufacturing Processes Through a Time-Based Classification Model

The ongoing crisis caused by the COVID-19 pandemic produced major reshuffles on the world map, bringing imbalance, uncertainty, and accumulated stress. Due to supply chain disruptions, the need for innovation has emerged both as a priority and a necessity and three-dimensional printing (3DP) proved to be a primary, smart, effective, and innovative additive manufacturing (AM) method. AM refers to the direct fabrication of complex geometries, using a computer-aided design (CAD) model or a three-dimensional scanner output. This article presents a literature review of AM technologies, chronologically sorted, and proposes a multilevel classification model. The suggested research approach appears a triangular methodology that encompasses the current ISO/ASTM 52900:2021 report. The first objective of this article is to form two double-level classification models of AM processes, depending on the technology and material factors. The second objective is to clarify in which of the proposed categories each AM process is included; and the third one is to investigate if the proposed taxonomy is related to the time spot, in which AM processes were invented. The contribution of this article lies in determining the factors that are crucial for the growth of AM ecosystem. The novelty of the proposed classification lies in the definition of an optimal option for each industrial application based on the different AM processes, the variety of materials, and the evolution of technology over the years. In this way, investing in AM is more systematic and less risky.

Polymeric long-acting drug delivery systems (LADDS) for treatment of chronic diseases: Inserts, patches, wafers, and implants

Non-oral long-acting drug delivery systems (LADDS) encompass a range of technologies for precisely delivering drug molecules into target tissues either through the systemic circulation or via localized injections for treating chronic diseases like diabetes, cancer, and brain disorders as well as for age-related eye diseases. LADDS have been shown to prolong drug release from 24 h up to 3 years depending on characteristics of the drug and delivery system. LADDS can offer potentially safer, more effective, and patient friendly treatment options compared to more invasive modes of drug administration such as repeated injections or minor surgical intervention. Whilst there is no single technology or definition that can comprehensively embrace LADDS; for the purposes of this review, these systems include solid implants, inserts, transdermal patches, wafers and in situ forming delivery systems. This review covers common chronic illnesses, where candidate drugs have been incorporated into LADDS, examples of marketed long-acting pharmaceuticals, as well as newly emerging technologies, used in the fabrication of LADDS.