Glutamine-Loaded Liposomes: Preliminary Investigation, Characterization, and Evaluation of Neutrophil Viability.

Glutamine has received attention due to its ability to ameliorate the immune system response. Once conventional liposomes are readily recognized and captured by immune system cells, the encapsulation of glutamine into those nanosystems could be an alternative to reduce glutamine dosage and target then to neutrophils. Our goals were to nanoencapsulate glutamine into conventional liposomes (Gln-L), develop an analytical high-performance liquid chromatography (HPLC) method for its quantification, and evaluate the viability of neutrophils treated with Gln-L. Liposomes were prepared using the thin-film hydration technique followed by sonication and characterized according to pH, mean size, zeta potential, and drug encapsulation efficiency (EE%). We also aimed to study the effect of liposomal constituent concentrations on liposomal characteristics. The viability of neutrophils was assessed using flow cytometry after intraperitoneal administration of free glutamine (Gln), Gln-L, unloaded-liposome (UL), and saline solution as control (C) in healthy Wistar rats. The selected liposomal formulation had a mean vesicle size of 114.65 ± 1.82 nm with a polydispersity index of 0.30 ± 0.00, a positive surface charge of 36.30 ± 1.38 mV, and an EE% of 39.49 ± 0.74%. The developed chromatographic method was efficient for the quantification of encapsulated glutamine, with a retention time at 3.8 min. A greater viability was observed in the group treated with glutamine encapsulated compared to the control group (17%), although neutrophils remain viable in all groups. Thus, glutamine encapsulated into liposomes was able to increase the number of viable neutrophils at low doses, thereby representing a promising strategy for the treatment of immunodeficiency conditions.

Ceftazidime and Usnic Acid Encapsulated in Chitosan-Coated Liposomes for Oral Administration against Colorectal Cancer-Inducing Escherichia coli.

Escherichia coli has been associated with the induction of colorectal cancer (CRC). Thus, combined therapy incorporating usnic acid (UA) and antibiotics such as ceftazidime (CAZ), co-encapsulated in liposomes, could be an alternative. Coating the liposomes with chitosan (Chi) could facilitate the oral administration of this nanocarrier. Liposomes were prepared using the lipid film hydration method, followed by sonication and chitosan coating via the drip technique. Characterization included particle size, polydispersity index, zeta potential, pH, encapsulation efficiency, and physicochemical analyses. The minimum inhibitory concentration and minimum bactericidal concentration were determined against E. coli ATCC 25922, NCTC 13846, and H10407 using the microdilution method. Antibiofilm assays were conducted using the crystal violet method. The liposomes exhibited sizes ranging from 116.5 ± 5.3 to 240.3 ± 3.5 nm and zeta potentials between +16.4 ± 0.6 and +28 ± 0.8 mV. The encapsulation efficiencies were 51.5 ± 0.2% for CAZ and 99.94 ± 0.1% for UA. Lipo-CAZ-Chi and Lipo-UA-Chi exhibited antibacterial activity, inhibited biofilm formation, and preformed biofilms of E. coli. The Lipo-CAZ-UA-Chi and Lipo-CAZ-Chi + Lipo-UA-Chi formulations showed enhanced activities, potentially due to co-encapsulation or combination effects. These findings suggest potential for in vivo oral administration in future antibacterial and antibiofilm therapies against CRC-inducing bacteria.

Isothermal titration calorimetry (ITC) as a promising tool in pharmaceutical nanotechnology.

Isothermal titration calorimetry (ITC) is a technique for evaluating the thermodynamic profiles of connection between two molecules, allowing the experimental design of nanoparticles systems with drugs and/or biological molecules. Taking into account the relevance of ITC, we conducted, therefore, an integrative revision of the literature, from 2000 to 2023, on the main purposes of using this technique in pharmaceutical nanotechnology. The search were carried out in the Pubmed, Sciencedirect, Web of Science, and Scifinder databases using the descriptors "Nanoparticles", "Isothermal Titration Calorimetry", and "ITC". We have observed that the ITC technique has been increasingly used in pharmaceutical nanotechnology, seeking to understand the interaction mechanisms in the formation of nanoparticles. Additionally, to understand the behavior of nanoparticles with biological materials (proteins, DNA, cell membranes, among others), thereby helping to understand the behavior of nanocarriers in vivo studies. As a contribution, we intended to reveal the importance of ITC in the laboratory routine, which is itself a quick and easy technique to obtain relevant results that help to optimize the nanosystems formulation process.

Nanotechnology and COVID-19: quo vadis?

The pandemic COVID-19 has worried everyone due to the high mortality rate and the high number of people hospitalized with severe acute respiratory syndrome caused by SARS-CoV-2. Given the seriousness of this disease, several companies and research institutions have sought alternative treatment and/or prevention methods for COVID-19. Due to its versatility, nanotechnology has allowed the development of protective equipment and vaccines to prevent the disease and reduce the number of severe COVID-19 cases. Thus, this article combined the main works and products developed in a nanotechnological field for COVID-19. We performed a literature search using the keywords "COVID-19," "SARS-CoV-2," "nanoparticles," "nanotechnology," and "liposomes" in the SciELO, Scifinder, PubMed, Sciencedirect, ClinicalTrials, and Nanotechnology Products databases Database. The data survey indicated 48 articles, 62 products, and 32 patents. The use of nanotechnology against COVID-19 has brought benefits in several parameters of this disease, helping develop rapid diagnostic tests that release the result in 10 min, as well as developing vaccines containing genetic material from SARS-CoV-2 (DNA, mRNA, and protein subunits). Nanotechnology is an exceptional ally against COVID-19, contributing to the most diverse areas, helping both prevent, diagnose, and treat COVID-19.

Nanotechnology and tuberculosis: An old disease with new treatment strategies.

Tuberculosis is an intracellular infectious disease caused by Mycobacterium tuberculosis, which mainly affects the lungs. Especially in patients infected by the Human Immunodeficiency Virus (HIV) or other immunosuppressed patients, tuberculosis is considered one of the infectious diseases with higher morbidity and mortality rates. Despite considerable improvements in diagnosis and treatment during the last decades, the drugs currently used in tuberculosis treatment still have limitations, such as low plasma levels after oral administration, low solubility in water, fast metabolization by the liver with a short 1/2 life and low patient adherence to treatment. Another limiting point is drug-resistant strains. Thus, to overcome such limitations, nanotechnology emerges as a promising alternative due to the drug release systems and its recent advances that show potential improvements, such as improved bioavailability and reduction of the therapeutic dose. In this context, this manuscript aimed to highlight the nanotechnology-based drug delivery systems studies pointing to those most effective for tuberculosis treatment. Studies based on polymeric nanoparticles are promising in diagnosing, treating, and even preventing tuberculosis because they have the high stability and transport capacity of these drugs. Solid lipid nanoparticles are another type of promising nanocarriers for treating tuberculosis, mainly for delivering drugs to the remote lymphatic system. Other promising nanosystems are the liposomes, since they have also shown efficacy in significantly reducing bacterial load compared to conventional drug administration. Given the results presented, the administration of drugs through nanotechnology-based drug delivery systems has benefits in treating tuberculosis since in vitro and in vivo studies have revealed that nanotechnology through nano- and micro-scale systems is an effective and promising approach for the treatment of tuberculosis. Furthermore, the increase in the number of patents for nanosystems aimed at treating TB has demonstrated researchers' commitment in the quest to improve the therapeutic arsenal against tuberculosis.

Does Oncocalyxone A (oncoA) have intrinsic fluorescence?

BACKGROUND: Oncocalyxone A (oncoA) is a quinone extracted from the Cordia oncocalyx plant. This compound has pharmacological properties, such as anti-inflammatory, analgesic, and cytotoxic activities, among others. OncoA presents a similar chemical structure to doxorubicin, a drug used in cancer treatment, which possesses an intrinsic fluorescence explored in various studies, including those using doxorubicin-loaded nanoparticles. Thus, due to the chemical structural similarity, the question arose whether oncoA could also show autofluorescence. Therefore, this study proposed to characterize the absorption and emission spectral profiles of oncoA and analyze if this compound could be used as a fluorescent probe. METHODS: For this, fucoidan-coated polyisobutylcyanoacrylate (PIBCA) nanoparticles containing oncoA were prepared, and an uptake study was performed using a human metastatic breast cancer cell line (MDA-MB-231 cells). RESULTS: OncoA presented a maximum emission wavelength in the blue region, near 430 nm, at 350 nm excitation, compatible with standard microscope optics. Fluorescence microscopy analyses showed that oncoA-loaded PIBCA nanoparticles were internalized by MDA-MB-231 cells under incubation times as shorter as 15 min. CONCLUSION: According to these findings, oncoA-encapsulated nanoparticles are promising fluorescent probes and could be useful for cellular uptake studies.

Protective mucus effect of the crude fraction of the mucus produced by the zoanthide Palythoa caribaeorum.

AIMS: This study aimed to evaluate the gastroduodenal protective action of crude fraction extracted from P. caribaeorum mucus in Wistar rats. MAIN METHOD: Initially, phytochemical screening was performed to measure secondary metabolites present in the extract. Subsequently, studies of gastroprotective action in Wistar rats were developed. The animals were randomly divided into six experimental groups: SF0.9% group, misoprostol group, and test groups (200, 100, 10, and 1 mg/kg) that received different doses of the crude fraction of zoanthid mucus (CFZM) diluted in SF0.9%. After 14 days of treatment, acute gastric ulcers were induced by gavage by administering aspirin (200 mg/kg). The stomach and duodenum were removed for histopathological and gene analysis of the mucosa. KEY FINDINGS: The present study found that all investigated metabolites showed negative results. The crude fraction showed a gastric and duodenal protective effect evidenced by an increase in the amount and production of mucins (MUC1 and MUC5AC) and mucus production area in the stomach. Histopathological analysis evidenced a decrease in epithelial damage in the duodenum, with a more significant extension of intestinal villi and a greater amount of goblet cells. SIGNIFICANCE: The crude fraction, extracted from P. caribaeorum, showed gastric and duodenal protective action and is not inert in murine gastroduodenal tissues.