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The influence of the introduction of structural modifiers citric acid and acetic acid on the morphology, luminescence properties and magnetic resonance imaging (MRI) tracer properties of GdPO 4 :Eu3+ micronanoparticles synthesized in ethanol system was investigated in the paper. In this system, GdPO 4 :Eu3+ micronanomaterials such as square flake, hexagram, waist drum morphologies can be prepared by adjusting ratios of structural modifier, phosphoric acid and gadolinium nitrate, respectively. In addition, the synthesized products were analyzed by field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FT-IR), fluorescence spectroscopy (PL), and magnetic resonance imaging (MRI) detection. The products were found to exhibit good crystallinity, particularly in terms of their luminescent properties, which exhibited notable differences. Overall, the luminescent properties of GdPO 4 :Eu3+ synthesized by citric acid modification were significantly enhanced compared with acetate modification, with at least five times more luminescent intensity than that of acetate modification. And amazingly, the GdPO 4 :Eu3+ luminescence intensity is strongest when the square flake-hexagram coexisting. The tracer properties of GdPO 4 :Eu3+ MRI with better luminescent square flake, hexagram, and square flake-hexagram coexisting morphologies were also investigated. It was found that the square flake had better T 1 -longitudinal relaxation imaging with a relaxation rate r 1 value of 0.79 mM−1s−1. This work is a good advancement for organic molecule-mediated modulation, synthesis of gadolinium phosphate-based rare-earth micronanomaterials and study of their applications in luminescence and MRI tracing. [ABSTRACT FROM AUTHOR]

Intravitreal (IVT) injection is an uncommon route of parenteral administration for therapeutic medications, but one of the most important for the treatment of ocular diseases, especially those related to macular degeneration. Nonetheless, there are currently no regulatory guidelines that specifically address how to establish a permitted daily exposure (PDE) for impurities and residual process reagents in IVT pharmaceutical drug products given the unique vulnerability of ocular tissues. The establishment of PDEs for IVT administration is complicated by the limited understanding of metabolism and clearance of small molecular weight chemicals from the human vitreous humor (VH), a problem compounded by the limited IVT-specific toxicological data. In this paper, we describe a feasible and comprehensive methodology for deriving PDE limits for impurities and residual process reagents from IVT drug products, as exemplified by five case studies, including inorganic elements, formic acid, polyethylene glycols, acetic acid, and caprolactam. The five case studies were selected to cover compounds with a wide range of impurity sources and toxicological data availability. The proposed framework considers both local ocular and systemic toxicity endpoints and advances the goal of a harmonized, science-based approach for deriving IVT PDE limits. • Regulatory agencies require that the levels of any impurities in drugs be safe. • These safe limits are termed Permitted Daily Exposure (PDE) values. • Intravitreal (IVT) injection is the rarest parenteral route of administration. • Regulatory guidelines do not specifically address the IVT route of administration. • We propose a framework for establishing IVT PDEs with five case studies. [ABSTRACT FROM AUTHOR]

Objective(s): Scientists have focused on the development of new drug delivery systems including pHsensitive nanomaterials adaptive to tumor microenvironments. We aimed to fabricate a microfluidic system to synthesize and characterize curcumin (Cur)-containing PCL and Chitosan (CSN) polymeric nanoparticles against MCF7 breast cancer cells. Materials and Methods: The microfluidic chip was fabricated by photolithography and polydimethylsiloxane (PDMS) molding procedure. The chip was Y-shaped and equipped with two inlets and one outlet. PCL and Chitosan (CSN) were dissolved in acetic acid overnight and mixed with Cur for three hours. The prepared solution was injected from one inlet and a solution of tween 80 in distilled water was injected from the other inlet. The nanoparticles were characterized in size, electrical charge, structure, drug loading, and drug release efficiency. Finally, the cytotoxicity was assessed using the MTT assay at specific concentrations after 24 and 48 hr. Results: The mean diameter/zeta potentials of spherical-shaped nanoparticles with and without Cur were 209 ±2 nm / +15 and 219 ± 4 nm/+3, respectively. FTIR results confirmed the presence of all components in the nanoparticles. The Cur loading rate was 1.5%, and Cur represented a sustained release manner. Also, the release profile showed faster release in a low-pH medium. MTT assay results showed that Cur-containing nanoparticles exerted a significant effect on cell viability. Conclusion: It can be concluded that microfluidic systems can pave the way for nanoparticle synthesis easily rapidly and cost-effectively for cancer agent delivery. Based on our observations, PCL-CSN-loaded Cur nanoparticles represent appropriate characteristics and suitable anti-cancer effects. [ABSTRACT FROM AUTHOR]