PPH Kosmed as the small/medium-sized enterprise studied and tried to bring into the market nanocosmetics to enhance efficiency and competitiveness of their products. Use of nanocosmetics is restricted because of potential toxicity of nanoparticles released during their application, as the released nanoparticles can penetrate into the skin. Therefore, nanocosmetics currently selected for the use do not release nanoparticles that can penetrate into the skin. Consequently, their health effects are evaluated basing on the analysis to characterize their activity on the skin surface. However, the introduction of new or modified nanocosmetics requires additional studies towards activity of nanoparticles which could penetrate deep into the skin.
Moreover, the restrictions on the use of nanocosmetics is due to their potential impact on the environment. Previous studies take account of the action of the released nanoparticles as active species and do not include the deactivation of the species under the environmental conditions.
It can be seen that the green/sustainable chemistry requirement fulfil conditions required for the placing of the new or modified nanocosmetics on the market.
Preparations currently used for the nanocosmetics correspond to the nanoparticles of transition metals and their oxides such as Ag, Au, TiO2, ZnO, Fe2O3 as well as relevant complexes structured to enhance processability or useful properties of the nanocomposites. Nowadays, efficient nanocosmetics were introduced including fullerene c60 and their derivatives. The fullerene act as antioxidants deactivating reactive oxygen species generated by ultraviolet radiation. Successful structuring of nanocosmetic results in improved performance and competitiveness, but require effective method of preparation of the nanoparticle suspensions as well as the additional studies throughout the above mentioned health- and environmental effects. For example, the above presented oxides reduce the effect of ultraviolet radiation selectively, depending on their nanoparticle sizes and the size distribution and, moreover, operate as stable components. Similarly, efficient are nanocosmetics containing fullerenes or derivative thereof. On the contrary, the effects of conventional cosmetics containing organic UV filters are neither so selective nor stable. On the other hand, the nanocosmetic preparation requires effective deagglomeration and dispersing that are hard to perform because of fast agglomeration of the active nanoparticles while the conventional homogenization proceeds smoothly.
Consequently, the objective of this work was the selection and testing of the efficient deagglomeration and dispersing of the nanoparticles which can be introduced into the R&D cycle of nanocosmetics.
As a result, continuous synthesizing of silver nanoparticles was successfully studied using modular microreactor of the Institute of Microtechnology in Mainz, Germany.
Generally, the modular microreactors coupled witch microstructured reactors allow study and development of chemical synthesis from the micro-scale to production scale, optionally via efficient deagglomeration and dispersing of reactants. A number of novel applications utilizing the micromixers can be seen to emerge in cosmetics. Efficient mixing of reactants and control of their concentrations result in optimised condition for the nanoparticle synthesis leading to relatively short nucleation times in the reaction mixture of high homogeneity. Therefore, microreactor systems produced narrower nanoparticle size distribution compared to the batch reactors of conventional size using similar ratios of reactants and experimental conditions. In the comparison, the use of microreactors reduce polydispersity of nanoparticulate products, and increase both inter-run reproducibility and throughput. Because, as mentioned above, the nanoparticles show size-dependent properties in the cosmetics, hence the accurate control of the particle size is essential here. Additionally, investigations dealing with the preparation of semi-solid pastes for cosmetic were undertaken at various industries. In a sum, the microreactors coupled with microstructured reactors with efficient mixing/dispersing module provide an excellent tool for synthesis of the useful nanoparticles. Generally, the coupled microreators that are fully automated and analytically equipped present a powerful synthesizing and screening tool for flow chemistry with which to perform substrate selection and process condition optimization at intermediary stages. Therefore, use of these microreactors enable intensification of the R&D cycle of nanocosmetics according to the both green/sustainable chemistry and market requirements.