Browsing by Author "Negro, Sofía"

Inhalation therapy is gaining increasing attention for the delivery of drugs destined to treat respiratory disorders associated with cytokine storms, such as COVID-19. The pathogenesis of COVID-19 includes an inflammatory storm with the release of cytokines from macrophages, which may be treated with anti-inflammatory drugs as celecoxib (CXB). For this, CXB-loaded PLGA microparticles (MPs) for inhaled therapy and that are able to be internalized by alveolar macrophages, were developed. MPs were prepared with 5% and 10% initial percentages of CXB (MP-C1 and MPC2). For both systems, the mean particle size was around 5 μm, which was adequate for macrophage uptake, and the mean encapsulation efficiency was >89%. The in vitro release of CXB was prolonged for more than 40 and 70 days, respectively. The uptake of fluorescein-loaded PLGA MPs by the RAW 264.7 macrophage cell line was evidenced by flow cytometry, fluorescence microscopy and confocal microscopy. CXB-loaded PLGA MPs did not produce cytotoxicity at the concentrations assayed. The anti-inflammatory activity of CXB (encapsulated and in solution) was evaluated by determining the IL-1, IL-6 and TNF-α levels at 24 h and 72 h in RAW 264.7 macrophages, resulting in a higher degree of reduction in the expression of inflammatory mediators for CXB in solution. A potent degree of gene expression reduction was obtained with the developed CXB-loaded MPs.

Alzheimer’s disease (AD) is the most prevalent neurodegenerative disorder, with its incidence constantly increasing. To date, there is no cure for the disease, with a need for new and effective treatments. Morin hydrate (MH) is a naturally occurring flavonoid of the Moraceae family with antioxidant and anti-inflammatory properties; however, the blood–brain barrier (BBB) prevents this flavonoid from reaching the CNS when aiming to potentially treat AD. Seeking to use the LAT-1 transporter present in the BBB, a nanoparticle (NPs) formulation loaded with MH and functionalized with phenylalanine-phenylalanine dipeptide was developed (NPphe-MH) and compared to non-functionalized NPs (NP-MH). In addition, two formulations were prepared using rhodamine B (Rh-B) as a fluorescent dye (NPphe-Rh and NP-Rh) to study their biodistribution and ability to cross the BBB. Functionalization of PLGA NPs resulted in high encapsulation efficiencies for both MH and Rh-B. Studies conducted in Wistar rats showed that the presence of phenylalanine dipeptide in the NPs modified their biodistribution profiles, making them more attractive for both liver and lungs, whereas non-functionalized NPs were predominantly distributed to the spleen. Formulation NPphe-Rh remained in the brain for at least 2 h after administration.

Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis and represents one of the leading causes of mortality worldwide due to multidrugresistant TB (MDR-TB). In our work, a new formulation of biodegradable PLGA microparticles was developed for pulmonary administration of gatifloxacin, using a surface modifier agent to actively target alveolar macrophages thereby allowing to gain access of the drug to Mycobacterium tuberculosis. For this, rapid uptake of the particles by macrophages is beneficial. This process was evaluated with fluorescein-loaded microparticles using PLGA 502 or PLGA 502H as polymers and labrafil as surface modifier. Cell phagocytosis was studied in raw 264.7 mouse macrophage cell line after 3, 5, 24, and 48 h incubation with the microparticles. Labrafil enhanced the uptake rate of PLGA 502H microparticles by macrophages which was directly related to the modification of the polymer matrix. Gatifloxacin-loaded PLGA microparticles using PLGA 502 or PLGA 502H and labrafil were prepared. From our results, only microparticles prepared with PLGA 502H and labrafil exhibited high encapsulation efficiency (89.6 ± 0.2%), rapid phagocytosis by macrophages (3 h), and remained inside the cells for at least 48 h, thereby resulting in a suitable carrier to potentially treat MDR-TB.

Rheumatoid arthritis (RA) is a chronic inflammatory disease with sulfasalazine (SSZ) extensively used for long-term treatment of both juvenile and adult RA. Its use is associated with adverse effects and toxicity due to its non-selective biodistribution. Macrophages play an important role in inflammatory processes. In order to target SSZ to macrophages in this work two microparticulate systems (MPs) are developed: SSZ-loaded PLGA MPs without and with -tocopherol, with particle sizes lower than 5 m and encapsulation efficiencies of 81.07 11% and 63.50 6.62%, respectively. Release of SSZ from MPs prepared with -tocopherol was prolonged for 20 days. In RAW264.7 cell macrophages MPs prepared with -tocopherol were captured faster. Cell viability studies confirmed that SSZ-loaded MPs prepared without and with -tocopherol did not produce cytotoxicity at the concentrations assayed. The anti-inflammatory activity of SSZ-loaded MPs was studied by quantifying interleukins IL-1, IL-6 and TNF- in macrophages. All formulations produced a significant reduction of cytokine concentrations after 24 and 72 h, indicating that release of SSZ from the MPs was able to inhibit the inflammatory response induced by lipopolysaccharide (LPS). Gene expression of IL-1, IL-6 and TNF- was decreased by SSZ-loaded MPs. SSZ-loaded MPs prepared with -tocopherol will potentially allow increasing the residence time of SSZ in the synovial cavity, prolonging its duration of action, and reducing the adverse effects associated with its non-selective biodistribution.