Evidence of the protective role of Carvacrol in a retinal degeneration animal model.

Neurodegenerative pathologies affecting the posterior segment of the eye, are characterized by being devastating and responsible for the majority of visual dysfunctions worldwide. These diseases are primarily degenerative, progressing chronically, and can inflict gradual harm to the optic nerve, retinal ganglion cells (RGC), photoreceptors, and other retinal cells. This retinal damage leads to a progressive loss of vision, marking these conditions as a significant health concern worldwide. The intravitreal administration of the phytochemical Carvacrol (CAR) is expected to demonstrate a neuroprotective and antiapoptotic effect on retinal cells, with a specific focus on RGC. This effect will be observed in a retinal degeneration model (RDM) in rabbits induced by cytotoxic and oxidative agents, namely glutamate (GLUT) and L-buthionine-S, R-sulfoximine (BSO). An in vivo study was conducted using New Zealand rabbits in which retinal damage was created to evaluate the effectiveness of CAR. The effectiveness of CAR on the functionality of retinal neuronal cells in RDM was evaluated using pupillary light reflection (PLR). Furthermore, the phytotherapeutic's influence on cell viability was determined through flow cytometry analysis. Finally, the neuroprotective and antiapoptotic capabilities of CAR were specifically scrutinized in RGC through histological studies, quantifying cell survival, and employing immunohistochemical assays to detect the apoptotic index (%) using the TUNEL technique. Our results demonstrated that CAR promoted the recovery of the pupillary contraction profile over time, maintaining the functionality of retinal cells as healthy controls. Additionally, it showed increased cell viability under oxidative and cytotoxic conditions given by GLUT-BSO agents. Finally, we found that CAR protects the survival of RGC and decreases the percentage of apoptotic cells when compared to RDM. CAR demonstrated to have positive effects on the functionality of photoreceptive nerve cells by restoring pupillary contraction. Likewise, it was shown to have neuroprotective and antiapoptotic effects when evaluated in a general and specific way on retinal nerve cells.

New RP-HPLC method for the simultaneous determination of process yield and percentage of encapsulation of Gallein in albumin nanoparticles.

A study was performed for the development and validation of a method of High Performance Liquid Chromatography (HPLC) for the identification and simultaneous quantification of Gallein and Human Serum Albumin (HSA). In addition, this work presents the development and physicochemical characterization of this new pharmaceutical formulation of HSA nanoparticles loaded with Gallein for potential use in the treatment of Alzheimer's disease. The method was developed with the purpose of determining the performance of the synthesis process of nanoparticles and the efficiency of encapsulation of the drug in the nanosystem. The HPLC mobile phase consisted of ACN:H2O:TEA:H3PO4 (50:49.8:0.1:0.1 v/v/v) pumped at a flow rate of 0.8 mL/min, isocratic mode, and the measurement were carried out at 220 nm. Chromatographic runs were performed on a C18 column (150 × 4.60 mm; 5 µm size particles). The HPLC-method was validated following the International Conference on Harmonisation (ICH) of Technical Requirements for Registration of Pharmaceuticals for Human Use guidelines and was used to simultaneously quantify the two components of the nanoformulation. Thus, the values obtained through the validated method were 43 % for drug encapsulation efficiency (% EE) and the synthesis performance (% yield) was 96 %. Moreover, the nanoformulation was characterized by DLS, the results showed that the average particle size was 217 nm, with a PDI of (0.085 ± 0.005) and a potential Z of -29.7 mV. Therefore, the developed method has proven useful in providing accurate simultaneous measurements of HSA and Gallein from albumin nanoparticles. It is advantageous since it is able to reduce the time and facilitate the determination of Gallein encapsulation efficiency and yield of albumin nanoparticles.

Bi-coloured enhanced luminescence imaging by targeted switch on/off laser MEF coupling for synthetic biosensing of nanostructured human serum albumin.

In this communication luminescent bioconjugated human serum albumin nanostructures (HSA NPs) with tiny ultraluminescent gold core-shell silica nanoparticles (Au@SiO2-Fl) were designed with enhanced bi-coloured luminescence properties. The HSA NPs were obtained from Human Serum Albumin free (HSA free) through the desolvation method, and Au@SiO2-Fl, through modified Turkevich and Störber methods. In this manner, porous HSA Nanostructures of 150.0-200 nm and Au@SiO2-Fl 45.0 nm final diameters were obtained. Both methodologies and structures were conjugated to obtain modified Nanocomposites based on tiny gold cores of 15 nm surrounded with well spatial Nanostructured architectures of HSA (d15 Au@SiO2-Fl-HSA) that generated variable nanopatterns depending on the modified methodology of synthesis applied within colloidal dispersions. Therefore, three methodologies of non-covalent conjugation were developed. In optimal conditions, through Transmission Electronic Microscopy (TEM), well resolved multilayered nano-architectures with a size 190.0-200 nm in average with variable contrast depending of the focused nanomaterial within the nanocomposite were shown. Optimized nanoarchitecture was based on a template tiny gold core-shell surrounded by nanostructured HSA NPs (d15 Au@SiO2-Fl-HSA). In this manner, the NanoImaging generated by laser fluorescence microscopy permitted to record improved optical properties and functionalities, such as: (i) enhanced ultraluminescent d15 Au@SiO2-Fl-HSA composites in comparison to individual components based on Metal Enhanced Fluorescence (MEF); (ii) diminished photobleaching; (iii) higher dispersibility; (iv) higher resolution of single bright nano-emitters of 210.0 nm sizes; and (v) enhanced bi-coloured Bio-MEF coupling with potential non-classical light delivery towards other non-optical active biostructures for varied applications. The characterization of these nanocomposites allowed the comparison, evaluation and discussion focused on new properties generated and functionalities based on the incorporation of different types of tuneable materials. In this context, the biocompatibility, Cargo confined spaces, protein-based materials, optical transparent could be highlighted, as well as optical active materials. Thus, the potential applications of nanotechnology to both nanomedicine and nano-pharmaceutics were discussed.

Development of melatonin-loaded, human-serum-albumin nanoparticles formulations using different methods of preparation for ophthalmic administration.

The use of proteins such as human serum albumin (HSA) to form nanometric systems seems very promising since they are non-toxic, biodegradable and have no antigenic activity. This molecule is ideal to transport insoluble drugs such as melatonin (Mel), which has antiapoptotic and antioxidant properties and appears promising for the treatment of neurodegenerative eye diseases. The objective of this study was to obtain nanoparticulate systems loaded with Mel, improving the conventional desolvation method. Systems were stabilised using two different strategies: one through the use of Eudragit S100 as a cross-linking agent and the other through thermal stabilisation. The systems thus obtained (Np-HSA-Eu-Mel and Np-HSA-Mel, respectively) were characterised and compared in terms of physicochemical and pharmacotechnical parameters. Whitish colloidal dispersions of nanometric size (≈170 nm), spherical shape, and monodisperse population were obtained. Besides, the pH was close to neutrality reaching 20 % drug encapsulation whereas the process performance was higher than 80 %. In FT-IR studies, thermal analysis and X-ray diffraction (XRD), the incorporation of the drug in the cavities of the nanoparticles could be evidenced. Regarding the physical stability of nanoparticles, for Np-HSA-Eu-Mel instability was observed at pH > 7. However, Np-HSA-Mel was able to remain stable at different pH levels. Mel release from these systems was consequently affected, where the former released faster than the active compared to the last. On the other hand, it was observed that the drying process (lyophilization in this case) applied to the nanoparticles suspensions does not affect their original properties after redispersion over a three months period. Likewise, the formulation did not produce irritation when administered topically, whereas when administered subconjunctivally, only slight irritation was observed 24 h after administration. According to the result of this study, the Np-HSA-Mel formulation could achieve advantageous properties as a vehicle for the transport of insoluble drugs for the treatment of neurodegenerative diseases at the ocular level.