Microneedles offer a convenient transdermal delivery route with potential for long term sustained release of drugs. However current microneedle technologies may not have the mechanical properties for reliable and stable penetration (e.g. hydrogel microneedles). Moreover, it is also challenging to realize microneedle arrays with large size and high flexibility. There is also an inherent upper limit to the amount and kind of drugs that can be loaded in the microneedles. In this paper, we present a new class of polymeric porous microneedles made from biocompatible and photo-curable resin that address these challenges. The microneedles are unique in their ability to load solid drug formulation in concentrated form. We demonstrate the loading and release of solid formulation of anesthetic and non-steroidal anti-inflammatory drugs, namely Lidocaine and Ibuprofen. Paper also demonstrates realization of large area (6 × 20 cm2) flexible and stretchable microneedle patches capable of drug delivery on any body part. Penetration studies were performed in an ex vivo porcine model supplemented through rigorous compression tests to ensure the robustness and rigidity of the microneedles. Detailed release profiles of the microneedle patches were shown in an in vitro skin model. Results show promise for large area transdermal delivery of solid drug formulations using these porous microneedles.

To overcome the shortcoming of conventional transarterial chemoembolization (cTACE) like high systemic release, a novel droplet-based flow-focusing microfluidic device was fabricated and the biocompatible poly(lactic-co-glycolic acid) (PLGA) magnetic drug-eluting beads transarterial chemoembolization (TACE) microspheres with tunable size and shell thickness were prepared via this device. Paclitaxel, as a model active, was loaded through O/O/W emulsion method with high efficiency. The size and the shell thickness vary when adjusting the flow velocity and/or solution concentration, which caters for different clinical requirements to have different drug loading and release behavior. Under the designed experimental conditions, the average diameter of the microspheres is 60 ± 2 μm and the drug loading efficiency has reached 6%. The drug release behavior of the microspheres shows the combination of delayed release and smoothly sustained release profiles and the release kinetics differ within different shell thickness. The microspheres also own the potential of magnetic resonance imaging (MRI) visuality because of the loaded magnetic nanoparticles. The microsphere preparation method and device we proposed are simple, feasible, and effective, which have a good application prospect.

To overcome the shortcoming of drug-loaded nanoparticles, such as high initial burst release and wide size distribution, a novel manufacturing technique for core–shell structure nanoparticle was developed by combining microfluidic chip and electrohydrodynamic atomization. In this study, the mixture solution of the surfactant 1, 2- dipalmitoyl-sn-glycero-3-phosphoglycerol and the polymeric coating material polylactic-glycolic-acid was introduced into the outer microchannel of the microfluidic chip as the particle’s shell. And the encapsulated drug paclitaxel was pumped into the inner microchannel as the core. Then, the particles with a nanoscale-size core–shell structure were generated by applying an electric field on the laminar flow which was formed in the microfluidic chip. Operation parameters, including working voltage, carrier material and surfactant concentration as well as liquid flow rates were optimized for nanoparticles generation. The properties of drug-loaded nanoparticles in terms of their particle size, zeta potential and encapsulation efficiency were investigated. Under the optimal experimental conditions, the particle size was approximately 145 nm and encapsulation efficiency reached 92%. Moreover, the drug release of these nanoparticles could be prolonged over a significant period for more than ten days. It can be expected that this innovative approach could provide a useful platform for drug-loaded core–shell nanoparticles developing.

No abstract

No abstract