Curcumin and quercetin co-encapsulated in nanoemulsions for nasal administration: A promising therapeutic and prophylactic treatment for viral respiratory infections.

One of the most frequent causes of respiratory infections are viruses. Viruses reaching the airways can be absorbed by the human body through the respiratory mucosa and mainly infect lung cells. Several viral infections are not yet curable, such as coronavirus-2 (SARS-CoV-2). Furthermore, the side effect of synthetic antiviral drugs and reduced efficacy against resistant variants have reinforced the search for alternative and effective treatment options, such as plant-derived antiviral molecules. Curcumin (CUR) and quercetin (QUE) are two natural compounds that have been widely studied for their health benefits, such as antiviral and anti-inflammatory activity. However, poor oral bioavailability limits the clinical applications of these natural compounds. In this work, nanoemulsions (NE) co-encapsulating CUR and QUE designed for nasal administration were developed as promising prophylactic and therapeutic treatments for viral respiratory infections. The NEs were prepared by high-pressure homogenization combined with the phase inversion temperature technique and evaluated for their physical and chemical characteristics. In vitro assays were performed to evaluate the nanoemulsion retention into the porcine nasal mucosa. In addition, the CUR and QUE-loaded NE antiviral activity was tested against a murine ß-COV, namely MHV-3. The results evidenced that CUR and QUE loaded NE had a particle size of 400 nm and retention in the porcine nasal mucosa. The antiviral activity of the NEs showed a percentage of inhibition of around 99 %, indicating that the developed NEs has interesting properties as a therapeutic and prophylactic treatment against viral respiratory infections.

Toward a Platform for the Treatment of Burns: An Assessment of Nanoemulsions vs. Nanostructured Lipid Carriers Loaded with Curcumin.

Curcumin is a highly promising substance for treating burns, owing to its anti-inflammatory, antioxidant, antimicrobial, and wound-healing properties. However, its therapeutic use is restricted due to its hydrophobic nature and low bioavailability. This study was conducted to address these limitations; it developed and tested two types of lipid nanocarriers, namely nanoemulsions (NE-CUR) and nanostructured lipid carriers (NLC-CUR) loaded with curcumin, and aimed to identify the most suitable nanocarrier for skin burn treatment. The study evaluated various parameters, including physicochemical characteristics, stability, encapsulation efficiency, release, skin permeation, retention, cell viability, and antimicrobial activity. The results showed that both nanocarriers showed adequate size (~200 nm), polydispersity index (~0.25), and zeta potential (~>-20 mV). They also showed good encapsulation efficiency (>90%) and remained stable for 120 days at different temperatures. In the release test, NE-CUR and NCL-CUR released 57.14% and 51.64% of curcumin, respectively, in 72 h. NE-CUR demonstrated better cutaneous permeation/retention in intact or scalded skin epidermis and dermis than NLC-CUR. The cell viability test showed no toxicity after treatment with NE-CUR and NLC-CUR up to 125 µg/mL. Regarding microbial activity assays, free curcumin has activity against P. aeruginosa, reducing bacterial growth by 75% in 3 h. NE-CUR inhibited bacterial growth by 65% after 24 h, and the association with gentamicin had favorable results, while NLC-CUR showed a lower inhibition. The results demonstrated that NE-CUR is probably the most promising nanocarrier for treating burns.

Development of a Novel Lipid-Based Nanosystem Functionalized with WGA for Enhanced Intracellular Drug Delivery.

Despite a considerable number of new antibiotics under going clinical trials, treatment of intracellular pathogens still represents a major pharmaceutical challenge. The use of lipid nanocarriers provides several advantages such as protection from compound degradation, increased bioavailability, and controlled and targeted drug release. Wheat germ agglutinin (WGA) is known to have its receptors on the alveolar epithelium and increase phagocytosis. The present study aimed to produce nanostructured lipid carriers with novel glycosylated amphiphilic employed to attach WGA on the surface of the nanocarriers to improve intracellular drug delivery. High-pressure homogenization was employed to prepare the lipid nanocarriers. In vitro, high-content analysis and flow cytometry assay was employed to study the increased uptake by macrophages when the nanocarriers were grafted with WGA. A lipid nanocarrier with surface-functionalized WGA protein (~200 nm, PDI > 0.3) was successfully produced and characterized. The system was loaded with a lipophilic model compound (quercetin; QU), demonstrating the ability to encapsulate a high amount of compound and release it in a controlled manner. The nanocarrier surface functionalization with the WGA protein increased the phagocytosis by macrophages. The system proposed here has characteristics to be further explored to treat intracellular pathogens.

Curcumin and Quercetin-Loaded Lipid Nanocarriers: Development of Omega-3 Mucoadhesive Nanoemulsions for Intranasal Administration.

Curcumin (CUR) and quercetin (QU) are potential compounds for treatment of brain diseases such as neurodegenerative diseases (ND) because of their anti-inflammatory and antioxidant properties. However, low water solubility and poor bioavailability hinder their clinical use. In this context, nanotechnology arises as a strategy to overcome biopharmaceutical issues. In this work, we develop, characterize, compare, and optimize three different omega-3 (ω-3) fatty acids nanoemulsions (NEs) loaded with CUR and QU (negative, cationic, gelling) prepared by two different methods for administration by intranasal route (IN). The results showed that formulations prepared with the two proposed methods exhibited good stability and were able to incorporate a similar amount of CUR and QU. On the other side, differences in size, zeta potential, in vitro release kinetics, and permeation/retention test were observed. Considering the two preparation methods tested, high-pressure homogenization (HPH) shows advantages, and the CQ NE- obtained demonstrated potential for sustained release. Toxicity studies demonstrated that the formulations were not toxic for Caenorhabditis elegans. The developed ω-3 fatty acid NEs have shown a range of interesting properties for the treatment of brain diseases, since they have the potential to increase the nose-to-brain permeation of CUR and QU, enabling enhanced treatments efficiency.

Glycyrrhizic Acid and Its Hydrolyzed Metabolite 18ß-Glycyrrhetinic Acid as Specific Ligands for Targeting Nanosystems in the Treatment of Liver Cancer.

Glycyrrhizic acid and its hydrolyzed metabolite 18ß-glycyrrhetinic acid, obtained from the plant Glycyrrhiza glabra, have numerous pharmacological activities, such as anti-inflammatory, anti-ulcerative, antiallergic, immunomodulatory, antiviral, antitumor, hepatoprotective, and antioxidant effects, and others. In addition to the pharmacological activities, in the 1980s, an interaction and uptake of these molecules by the liver was verified, which was later confirmed by other studies through the discovery of specific receptors in the hepatocytes. The presence of these specific receptors in the liver led to vectorization and delivery of drugs, by the introduction of glycyrrhizic acid or glycyrrhetinic acid on the surface of nanosystems, for the treatment of liver diseases. This review describes experimental evidence of vectorization by conjugating glycyrrhizic acid or glycyrrhetinic acid to nanosystems and delivery of antitumor drugs for the treatment of liver cancer and also describes the techniques used to perform this conjugation. We have shown that due to the existence of specific receptors for these molecules, in addition to the targeting of nanosystems to hepatocytes, nanosystems having glycyrrhizic acid or glycyrrhetinic acid on their surface had the same therapeutic effect in a significantly lower dose compared to the free drug and unconjugated nanosystems, with consequent reduction of side effects and toxicity.

Nanoemulsion Improves the Neuroprotective Effects of Curcumin in an Experimental Model of Parkinson's Disease.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by motor dysfunction. Recent studies have shown that curcumin (CUR) has neuroprotective effects in PD experimental models. However, its efficacy is limited due to low water solubility, bioavailability, and access to the central nervous system. In this study, we compared the effects of new curcumin-loaded nanoemulsions (NC) and free CUR in an experimental model of PD. Adult Swiss mice received NC or CUR (25 and 50 mg/kg) or vehicle orally for 30 days. Starting on the eighth day, they were administered rotenone (1 mg/kg) intraperitoneally until the 30th day. At the end of the treatment, motor assessment was evaluated by open field, pole test, and beam walking tests. Oxidative stress markers and mitochondrial complex I activity were measured in the brain tissue. Both NC and CUR treatment significantly improved motor impairment, reduced lipoperoxidation, modified antioxidant defenses, and prevented inhibition of complex I. However, NC was more effective in preventing motor impairment and inhibition of complex I when compared to CUR in the free form. In conclusion, our results suggest that NC effectively enhances the neuroprotective potential of CUR and is a promising nanomedical application for PD.

Development of Lipid Nanocarriers for Tuberculosis Treatment: Evaluation of Suitable Excipients and Nanocarriers.

BACKGROUND: Lipid nanocarriers have been widely tested as drug delivery systems to treat diseases due to their bioavailability, controlled release, and low toxicity. For the pulmonary route, the Food and Drug Administration favors the use of substances generally recognized as safe, as well as biodegradable and biocompatible to minimize the possibility of toxicity. Tuberculosis (TB) remains a public health threat worldwide, mainly due to the long treatment duration and adverse effects. Therefore, new drug delivery systems for treating TB are needed. OBJECTIVE: Physicochemical characterization of different lipid-based nanocarriers was used to optimize carrier properties. Optimized systems were incubated with Mycobacterium tuberculosis to assess whether lipid-based systems act as the energy source for the bacteria, which could be counterproductive to therapy. METHODS: Several excipients and surfactants were evaluated to prepare different types of nanocarriers using high-pressure homogenization. RESULTS: A mixture of trimyristin with castor oil was chosen as the lipid matrix after differential scanning calorimetry analysis. A mixture of egg lecithin and PEG-660 stearate was selected as an optimal surfactant system, as this mixture formed the most stable formulations. Three types of lipid nanocarriers, solid lipid nanoparticles, nanostructured lipid carriers (NLC), and nanoemulsions, were prepared, with the NLC systems showing the most suitable properties for further evaluation. It may provide the advantages of increasing the entrapment efficiency, drug release, and the ability to be lyophilized, producing powder for pulmonary administration as an alternative to entrap poor water-soluble molecules. CONCLUSION: Furthermore, the NLC system can be considered for use as a platform for the treatment of TB through the pulmonary route.

Anti-inflammatory and Antioxidant Effects of the Microalga Pediastrum boryanum in Carrageenan-Induced Rat Paw Edema

Abstract The potential use of microalgae in health has been the aim of different studies in the last years. This study investigated anti-inflammatory and antioxidant properties of three different extracts of green microalga Pediastrum boryanum in an acute inflammation model in rats. Rats were treated intraperitoneally with lyophilized biomass, the phenolic compounds and the extracellular extracts of P. boryanum before the induction of paw edema by the intraplantar injection of carrageenan. The edema and the levels of interleukin-1β and tumor necrosis factor-α were determined in the hind paw. Oxidative stress markers were analyzed in the liver and hepatic toxicity and genetic damage was evaluated in the blood. The results demonstrated that the three extracts of P. boryanum exhibited pronounced anti-oedematous property and decreased the levels of cytokines. The best results were provided by the phenolic compounds extract, that contains gallic, chlorogenic, protocathecuic and vanillic acid. A reduction in lipid peroxidation was observed after the treatment with lyophilized biomass and the extracellular extract improved the total antioxidant capacity of the liver. Moreover, no DNA damage and hepatic toxicity were observed after administration of P. boryanum extracts. In conclusion, these results suggest that P. boryanum can be an important source of anti-inflammatory compounds.

Curcumin and Quercetin-Loaded Nanoemulsions: Physicochemical Compatibility Study and Validation of a Simultaneous Quantification Method.

Biphasic oil/water nanoemulsions have been proposed as delivery systems for the intranasal administration of curcumin (CUR) and quercetin (QU), due to their high drug entrapment efficiency, the possibility of simultaneous drug administration and protection of the encapsulated compounds from degradation. To better understand the physicochemical and biological performance of the selected formulation simultaneously co-encapsulating CUR and QU, a stability test of the compound mixture was firstly carried out using X-ray powder diffraction and thermal analyses, such as differential scanning calorimetry (DSC) and thermogravimetric analyses (TGA). The determination and quantification of the encapsulated active compounds were then carried out being an essential parameter for the development of innovative nanomedicines. Thus, a new HPLC-UV/Vis method for the simultaneous determination of CUR and QU in the nanoemulsions was developed and validated. The X-ray diffraction analyses demonstrated that no interaction between the mixture of active ingredients, if any, is strong enough to take place in the solid state. Moreover, the thermal analysis demonstrated that the CUR and QU are stable in the nanoemulsion production temperature range. The proposed analytical method for the simultaneous quantification of the two actives was selective and linear for both compounds in the range of 0.5-12.5 µg/mL (R2 > 0.9997), precise (RSD below 3%), robust and accurate (recovery 100 ± 5 %). The method was validated in accordance with ICH Q2 R1 "Validation of Analytical Procedures" and CDER-FDA "Validation of chromatographic methods" guideline. Furthermore, the low limit of detection (LOD 0.005 µg/mL for CUR and 0.14 µg/mL for QU) and the low limit of quantification (LOQ 0.017 µg/mL for CUR and 0.48 µg/mL for QU) of the method were suitable for the application to drug release and permeation studies planned for the development of the nanoemulsions. The method was then applied for the determination of nanoemulsions CUR and QU encapsulation efficiencies (> 99%), as well as for the stability studies of the two compounds in simulated biological fluids over time. The proposed method represents, to our knowledge, the only method for the simultaneous quantification of CUR and QU in nanoemulsions.

Development of Nasal Lipid Nanocarriers Containing Curcumin for Brain Targeting.

BACKGROUND: Curcumin (CUR) has properties that can be useful for the treatment of Alzheimer's disease. Such properties are the inhibition of amyloid-ß-protein (Aß) aggregation, Aß-induced inflammation, and activities of ß-secretase and acetylcholinesterase. However, previous studies have revealed that CUR exhibited low bioavailability and difficulties in reaching the brain. OBJECTIVE: To overcome such drawbacks, this study aims at developing nasal lipid nanocarriers loaded with CUR to effectively target the brain. METHODS: The lipid nanocarriers (NE) were prepared using the hot solvent diffusion associated with the phase inversion temperature methods. Physico-chemical and morphological characterizations and in vitro drug release of the nanocarriers were carried out. The CUR permeation/retention was analyzed in Franz-type diffusion cell using porcine nasal mucosa. Confocal laser scan and histopathological studies were also performed. RESULTS: The results showed that the NE sizes ranged between 18 nm and 44 nm with negative zeta potential. The CUR content ranged from 0.24 to 1.50 mg/mL with an encapsulation efficiency of 99%. The profiles of CUR release indicated a biphasic kinetics. CUR-NE permeation across the porcine nasal mucosa was higher when compared to free CUR. These results have also been validated through an analysis on a confocal microscopy. In addition, no toxicity on the nasal mucosa has been observed in a histopathological analysis. CONCLUSION: These results suggest that it is possible to develop NEs with a high content of CUR and small particle size. Such an encapsulation increases the potential of CUR permeation across the porcine nasal mucosa.

Anti-inflammatory Effect and Toxicology Analysis of Oral Delivery Quercetin Nanosized Emulsion in Rats.

PURPOSE: This study evaluates the advantage of the quercetin encapsulation in nanosized emulsion (QU-NE) administered orally in rats in order to demonstrate its anti-oedematous and antioxidant effects as well as its toxicity. METHODS: The nanocarriers were prepared using the hot solvent diffusion with the phase inversion temperature methods. The nanocarriers physicochemical properties were then investigated. The anti-edematous activity was tested using paw edema in rats. In addition, NF-kB expression in subcutaneous tissue of the paws was accessed by immunohistochemistry while the lipid peroxidation was analyzed in the liver by malondialdehyde reaction with thiobarbituric acid. Hematological, renal and hepatic toxicity as well as the genetic damage were also evaluated. RESULTS: The results demonstrated that QU-NE exhibited pronounced anti-oedematous property comparable to drug diclofenac. This effect was associated with NF-κB pathway inhibition. The lipid peroxidation was also only reduced in rats treated with QU-NE. Besides this, no genetic damage, hematological, renal or hepatic toxicities were observed after administration of QU-NE. CONCLUSIONS: These results suggest that quercetin nanosized emulsion exhibits anti-oedematous and antioxidant properties and does not demonstrate toxic effects. This indicates that it has a potential application in the treatment of inflammatory diseases.