This article will provide an overview of recent developments for microneedles made using injection molding and hot embossing techniques for active transdermal drug delivery. Microneedle arrays are developed for pain‐free and efficient drug delivery without using a cold chain. The focus of this article will be on the use of engineering thermoplastics and microneedle manufacturing techniques including patterning. Recent developments demonstrate that commercialization of polymer‐based microneedle systems is feasible. POLYM. ENG. SCI., 59:877–890, 2019. © 2019 Society of Plastics Engineers

No abstract

In this study the viscosity behavior of the polymer-based drug delivery system (Soluplus-Fenofibrate) at high shear rates was investigated using (i) Computational Fluid Dynamics (CFD) methods and (ii) experimental data acquired with a high-pressure capillary rheometer. The barrel and capillary were rebuilt in the virtual domain by means of finite-volume methods and used for fluid dynamic simulations. Our primary focus was on validating the Carreau-Winter and Yasuda material models in the Open Field Operation and Manipulation program (OpenFOAM) and investigating their usefulness in this type of simulation.First, the models were fitted to experimental data from a well-known system -p olystyrenet ype (145D, BASF). The results showed that the Yasuda model fit must be applied to obtain the correct material properties when simulating a non-Newtonian melt flow in aw ide range of shear rates. The Carreau-Winter model was found to be valid only in the zero shear-rate viscosity region. On the basis of these findings, the Soluplus-Fenofibrate system was subsequently characterized and simulated. We observed that Fenofibrate (lipid-regulating agent) acts as ap lasticizer in this polymer system and decreases system viscosity at lower shear rates compared to pure the Soluplus (polyvinyl caprolactam-polyvinyl acetatepolyethylene glycol graft copolymer) at the same temperatures.Our results show that the viscosity models can be implemented accurately even for processes with high shear rates, which also involve high temperatures. 1I ntroductionThe increasing abundance of poorly soluble drug structures has created an urgent need for more effective dosage forms (Kolter et al., 2012) that should enable better dissolution of an active pharmaceutical ingredient (API) in ap atient's body. This would make medical treatments not only more effective, but also more economical, since smaller amounts of drugs are needed. In recent decades, several polymers have been spe-cially designed to enhance the solubility and thus the bioavailability of API's (Miller-Chou et al., 2002). API's are dispersed in such polymers (API carrier matrix) forming aso-called solid dispersion (Lipinski et al., 2001). Dhirendra et al. (2009) have recently published an overview of possible solid dispersion systems. According to Butler et al. (2009), the API's bioavailability may be heavily influenced by whether it is in the amorphous or the crystalline phase. To prepare pharmaceutical various types of solid dispersions (dispersed systems), several techniques, such as spray drying, freeze drying, supercritical fluid drying and hot-melt extrusion, are available (Kolter et al., 2012). Among these, hot-melt extrusion has become increasingly popular. According to Breitenbach (2002), various solid dispersions can be produced by hot-melt extrusion in the absence of solvents through afast and continuous low-cost process. The extruded filament is cut into 2mmp ellets and processed further. The subsequent multistep procedure, which includes steps such as milling the pellets and p...