*A Microfluidic Device as a Drug Carrier DOI: http://dx.doi.org/10.5772/intechopen.102052*

technologies that rely on emulsion or self-assembly on the shape of the equipment used do not always provide fine, pre-designed control over particle geometry (shape, aspect ratio) and composition [46]. A microchannel flow-focusing system (EDCl) was used to study the manufacture of HANP cross-linked with adipic acid hydrazide (ADH) and chlorinated carbodiimide. The focus of this work is to analyze the process parameters of this unique method, which is a continuous nanoprecipitation at the water-organic solvent interface. The influence of the type of organic solvent used, the flow rate of the non-solvent, and the content of hyaluronic acid (HA) on the HANP characteristics of (hyaluronic acid nanoparticles) [47]. Several studies have found that the affinity between water and organic solvents influences the average diameter of nanoparticles (NPs) via water diffusion and the rate of nanoprecipitation. When the non-solvent shows a moderate affinity for water, the polydispersity becomes narrower. In addition, since the process is regulated by convection, lower HA concentrations and higher isopropanol flow rates will produce smaller particles. Regardless of the organic solvent, flow rate, or HA concentration, some stable NPs are formed. The process was found to be simple, repeatable, and fast. This process is expected to be used in the manufacture of oil-free HANP, which is important for medical, pharmacological, and cosmetic applications, as shown in **Table 1** [45, 47].
