Steroids are compounds widely available in nature and synthesized for therapeutic and medical purposes. Although several analytical techniques are available for the quantification of steroids, their analysis is challenging due to their low levels and complex matrices of the samples. The efficiency and quick separation of the HPLC combined with the sensitivity, selectivity, simplicity, and cost-efficiency of fluorescence, make HPLC coupled to fluorescence detection (HPLC-FLD) an ideal tool for routine measurement and detection of steroids. In this review, we covered HPLC-FLD methods reported in the literature for the steroids quantification in clinical, pharmaceutical, and environmental applications, focusing on the various approaches of fluorescent derivatization. The aspects related to analytical methodology including sample preparation, derivatization reagents, and chromatographic conditions will be discussed.

A new system composed of chitosan nanoparticles loaded with methotrexate (MTX-CS-NPs) and functionalized with photocatalytic TiO2 nanoparticles (TiO2-NPs) was prepared. This system is expected to initiate polymeric rupture of MTX-CS-NPs and subsequently release MTX, upon illumination with UV light. MTX-CS-NPs were prepared and characterized in terms of particle size, charge, polydispersity and drug release before and after coating with TiO2-NPs. The release of MTX in vitro was studied in dark, light and UV light. Finally, coated and uncoated MTX-CS-NPs were studied in vitro using MCF-7 cell line. The functionalized NPs were larger in size, more polydisperse and carried higher positive charges compared to the unfunctionalized NPs. The entrapment efficacy was high reaching 75% and was not affected by coating with MTX-CS-NPs. Further, less than 5% of methotrexate was released after 80 h from uncoated NPs and the release was not enhanced by UV illumination of the particles. In contrast, the release from functionalized NPs was enhanced, reaching 40% after 80 h, as the particles were stroked with UV light and as the amount of TiO2-NPs used in coating increased. Finally, coating the MTX-CS-NPs with TiO2-NPs significantly enhanced their cytotoxicity on MCF-7 cells. The coated MTX-CS-NPs recorded low cell viabilities compared to the other formulations. In conclusion, the drug release of MTX-CS-NPs could be triggered and controlled remotely by coating with TiO2-NPs, which maybe more effective in cancer treatment.

No abstract