Curcumin Loaded PEGylated Nanoemulsions Designed for Maintained Antioxidant Effects and Improved Bioavailability: A Pilot Study on Rats

When conventional approach in toxicity assays falls short for nanomedicines: a case study with nanoemulsions

The aim of this study was to assess the critical quality attributes of parenteral nanoemulsion formulations by measuring several physicochemical parameters and linking them to their in vitro performance, illustrating how simplistic and routinely used approaches are insufficient for understanding a potential nanomedicine. Physicochemical characterization should encompass size and size distribution through at least two orthogonal techniques, such as dynamic light scattering (DLS) and electron microscopy, with added value from analytical ultracentrifugation. In vitro toxicity assessment was performed using three different assays to determine mitochondrial activity (WST-1), membrane integrity (lactate dehydrogenase release (LDH) assay), and cell viability (propidium iodide (PI) staining). Special focus was placed on estimating appropriate incubation times for relevant results in biological investigations. All formulations had an average diameter of around 100 nm. Conclusions regarding in vitro safety were assay-dependent: LDH and PI-based assays showed good correlation, while the WST-1 assay indicated that the non-PEGylated formulation altered mitochondrial activity more significantly compared to the PEGylated ones. The study underlined that the selection of appropriate cytotoxicity assays should be based on the possible mechanism of cellular perturbation. Alternatively, different aspects of cellular toxicity should be tested. Additionally, there is a need for well-designed controls to overcome nanoparticle scattering effects and avoid potentially false high toxicity results, which was demonstrated. Combining orthogonal, well-designed physicochemical and biological assays in a standardized manner as an initial step in the reliable preclinical characterization of nanomedicines is suggested. This represents a key aspect of new methodologies in nanomedicine characterization.

Defining the mechanisms behind the hepatoprotective properties of curcumin

As a critical cause of human dysfunctionality, hepatic failure leads to approximately two million deaths per year and is on the rise. Considering multiple inflammatory, oxidative, and apoptotic mechanisms behind hepatotoxicity, it urges the need for finding novel multi-targeting agents. Curcumin is a phenolic compound with anti-inflammatory, antioxidant, and anti-apoptotic roles. Curcumin possesses auspicious health benefits and protects against several diseases with exceptional safety and tolerability. This review focused on the hepatoprotective mechanisms of curcumin. The need to develop novel delivery systems of curcumin (e.g., nanoparticles, self-micro emulsifying, lipid-based colloids, solid lipid nanoparticles, cyclodextrin inclusion, phospholipid complexes, and nanoemulsions) is also considered.

A Concise Review on Effect of PEGylation on the Properties of Lipid-Based Nanoparticles

Nanoparticle-based drug delivery systems have emerged as promising platforms for enhancing therapeutic efficacy while minimizing off-target effects. Among various strategies employed to optimize these systems, polyethylene glycol (PEG) modification, known as PEGylation-the covalent attachment of PEG to nanoparticles, has gained considerable attention for its ability to impart stealth properties to nanoparticles while also extending circulation time and improving biocompatibility. PEGylation extends to different drug delivery systems, in specific, nanoparticles for targeting cancer cells, where the concentration of drug in the cancer cells is improved by virtue of PEGylation. The primary challenge linked to PEGylation lies in its confirmation. Numerous research findings provide comprehensive insights into selecting PEG for various PEGylation methods. In this review, we have endeavored to consolidate the outcomes concerning the choice of PEG and diverse PEGylation techniques.

Multimodal evaluation of drug antibacterial activity reveals cinnamaldehyde analog anti-biofilm effects against Haemophilus influenzae

Biofilm formation by the pathobiont Haemophilus influenzae is associated with human nasopharynx colonization, otitis media in children, and chronic respiratory infections in adults suffering from chronic respiratory diseases such as chronic obstructive pulmonary disease (COPD). β-lactam and quinolone antibiotics are commonly used to treat these infections. However, considering the resistance of biofilm-resident bacteria to antibiotic-mediated killing, the use of antibiotics may be insufficient and require being replaced or complemented with novel strategies. Moreover, unlike the standard minimal inhibitory concentration assay used to assess antibacterial activity against planktonic cells, standardization of methods to evaluate anti-biofilm drug activity is limited. In this work, we detail a panel of protocols for systematic analysis of drug antimicrobial effect on bacterial biofilms, customized to evaluate drug effects against H. influenzae biofilms. Testing of two cinnamaldehyde analogs, (E)-trans-2-nonenal and (E)-3-decen-2-one, demonstrated their effectiveness in both H. influenzae inhibition of biofilm formation and eradication or preformed biofilms. Assay complementarity allowed quantifying the dynamics and extent of the inhibitory effects, also observed for ampicillin resistant clinical strains forming biofilms refractory to this antibiotic. Moreover, cinnamaldehyde analog encapsulation into poly(lactic-co-glycolic acid) (PLGA) polymeric nanoparticles allowed drug vehiculization while maintaining efficacy. Overall, we demonstrate the usefulness of cinnamaldehyde analogs against H. influenzae biofilms, present a test panel that can be easily adapted to a wide range of pathogens and drugs, and highlight the benefits of drug nanoencapsulation towards safe controlled release.

Evaluation of curcumin-based ophthalmic nano-emulsion on atropine-induced dry eye in mice

Background

One of the most efficient treatments for dry eye syndrome (DES) is to use nanocarriers as a potential delivery system. We aim to evaluate curcumin in a nano emulsion formulation.

Methods

A new formulation containing 5.5% curcuminoid was used. DLS, Zeta potential, TEM, and HPLC tests were performed to determine the size and morphology. First, 30 mice were selected as atropine-induced dry eye models. Next, 25 mice in 5 groups were treated with the nano emulsion at different doses, and corneal tissues were separated for evaluation.

Results

The DLS test results were indicative of the particles' stability. Nano curcumin appeared to be thoroughly effective in all groups, with the highest dose showing the most similarity to the healthy control group.

Conclusions

Curcumin-based nano emulsion eye drop is a promising candidate for DES management. However, further investigation is required to evaluate the possible risks in humans.

Pharmacokinetics, biodistribution, and in vivo toxicity of 7-nitroindazole loaded in pegylated and non-pegylated nanoemulsions in rats

Sepsis is a life-threatening condition caused by a dysregulated host response to infection. The development of sepsis is associated with excessive nitric oxide (NO) production, which plays an important role in controlling vascular homeostasis. 7-nitroindazole (7-NI) is a selective inhibitor of neuronal nitric oxide synthase (NOS-1) with potential application for treating NO imbalance conditions. However, 7-NI exhibits a low aqueous solubility and a short plasma half-life. To circumvent these biopharmaceutical limitations, pegylated (NEPEG7NI) and non-pegylated nanoemulsions (NENPEG7NI) containing 7-NI were developed. This study evaluates the pharmacokinetic profiles and toxicological properties of 7-NI loaded into the nanoemulsions. After a single intravenous administration of the free drug and the nanoemulsions at a dose of 10 mg.kg-1 in Wistar rats, 7-NI was widely distributed in the organs. The pharmacokinetic parameters of Cmax, t1/2, and AUC0-t were significantly increased after administration of the NEPEG7NI, compared to both free 7-NI and NENPEG7NI (p < 0.05). No observable adverse effects were observed after administering the free 7-NI, NEPEG7NI, or NENPEG7NI in the animals after a single dose of up to 3.0 mg.kg-1. The results indicated that 7-NI-loaded nanoemulsions are safe, constituting a promising approach to treating sepsis.

An Updated Review on Nanoemulsion: Factory for Food and Drug Delivery

BACKGROUND

A nanoemulsion is a colloidal system of small droplets dispersed in another liquid. It has attracted considerable attention due to its unique properties and various applications. Throughout this review, we provide an overview of nanoemulsions and how they can be applied to various applications such as drug delivery, food applications, and pesticide formulations.

OBJECTIVE

This updated review aims to comprehensively overview nanoemulsions and their applications as a versatile platform for drug delivery, food applications, and pesticide formulations.

METHODS

Research relevant scientific literature across various databases, including PubMed, Scopus, and Web of Science. Suitable keywords for this purpose include "nanoemulsion," "drug delivery," and "food applications." Ensure the search criteria include recent publications to ensure current knowledge is included.

RESULTS

Several benefits have been demonstrated in the delivery of drugs using nanoemulsions, including improved solubility, increased bioavailability, and controlled delivery. Nanoemulsions have improved some bioactive compounds in food applications, including vitamins and antioxidants. At the same time, pesticide formulations based on nanoemulsions have also improved solubility, shelf life, and effectiveness.

CONCLUSION

The versatility of nanoemulsions makes them ideal for drug delivery, food, and pesticide formulation applications. These products are highly soluble, bioavailable, and targeted, providing significant advantages. More research and development are required to implement nanoemulsion-based products on a commercial scale.

Lipid-like gemcitabine diester-loaded liposomes for improved chemotherapy of pancreatic cancer

Gemcitabine (GEM) is a non-selective chemotherapeutic agent used in the treatment of pancreatic cancer. Its antitumor efficacy is limited by a short plasma half-life and severe adverse reactions. To overcome these shortcomings, four novel lipid-like GEM diesters were synthesized and encapsulated into liposomes. Through optimization, dimyristoyl GEM (dmGEM)-loaded liposomes (LipodmGEM) were successfully obtained with an almost complete encapsulation efficiency. Compared to free GEM, LipodmGEM showed enhanced cellular uptake and cell apoptosis, improved inhibition of cell migration on AsPC-1 cells and a greatly extended half-life (7.22 vs. 1.78 h). LipodmGEM succeeded in enriching the drug in the tumor (5.28 vs. 0.03 μmol/g at 8 h), overcoming a major shortcoming of GEM, showed excellent anticancer efficacy in vivo and negligible systemic toxicity, superior to GEM. Attractive as well, suspensions of LipodmGEM remained stable at 2-10 °C away from light for no <2 years. Our results suggest that LipodmGEM might become of high interest for treating pancreatic cancer while the simple strategy we reported might be explored as well for converting other antitumor drugs with high water-solubility and short plasma half-life into attractive nanomedicines.

A critical review of the novelties in the development of intravenous nanoemulsions

Nanoemulsions have gained increasing attention in recent years as a drug delivery system due to their ability to improve the solubility and bioavailability of poorly water-soluble drugs. This systematic review aimed to collect and critically analyze recent novelties in developing, designing, and optimizing intravenous nanoemulsions appearing in articles published between 2017 and 2022. The applied methodology involved searching two electronic databases PubMed and Scopus, using the keyword "nanoemulsion" in combination with "intravenous" or "parenteral". The resulting original articles were classified by the method of preparation into different categories. An overview of the current methods used for the preparation of such formulations, including high- and low-energy emulsification, was provided. The advantages and disadvantages of these methods were discussed, as well as their potential impact on the properties of the developed intravenous nanoemulsions. The problem of inconsistency in intravenous nanoemulsion terminology may lead to misunderstandings and misinterpretations of their properties and applications was also undertaken. Finally, the regulatory aspects of intravenous nanoemulsions, the state of the art in the field of intravenous emulsifiers, and the future perspectives were presented.

Development and Characterization of a Hydrogel Containing Curcumin-Loaded Nanoemulsion for Enhanced In Vitro Antibacteria and In Vivo Wound Healing

Curcumin (CUR) is a natural compound extracted from turmeric (Curcuma longa L.) used to cure acne, wound healing, etc. Its disadvantages, such as poor solubility and permeability, limit its efficacy. Nanoemulsion (NE)-based drug delivery systems have gained popularity due to their advantages. This study aimed to optimize a CUR-NE-based gel and evaluate its physicochemical and biological properties. A NE was prepared using the catastrophic phase inversion method and optimized using the Design Expert 12.0 software. The CUR-NE gel was characterized in terms of visual appearance, pH, drug release, antibacterial and wound healing effects. The optimal formulation contained CUR, Capryol 90 (oil), Labrasol:Cremophor RH40 (1:1) (surfactants), propylene glycol (co-surfactant), and water. The NE had a droplet size of 22.87 nm and a polydispersity index of 0.348. The obtained CUR-NE gel had a soft, smooth texture and a pH of 5.34 ± 0.05. The in vitro release of CUR from the NE-based gel was higher than that from a commercial gel with nanosized CUR (21.68 ± 1.25 µg/cm2, 13.62 ± 1.63 µg/cm2 after 10 h, respectively). The CUR-NE gel accelerated in vitro antibacterial and in vivo wound healing activities as compared to other CUR-loaded gels. The CUR-NE gel has potential for transdermal applications.

Curcumin: Overview of Extraction Methods, Health Benefits, and Encapsulation and Delivery Using Microemulsions and Nanoemulsions

Curcumin is the principal curcuminoid found in the rhizomes of turmeric. Due to its therapeutic action against cancer, depression, diabetes, some bacteria, and oxidative stress, it has been used widely in medicine since ancient times. Due to its low solubility, the human organism cannot completely absorb it. Advanced extraction technologies, followed by encapsulation in microemulsion and nanoemulsion systems, are currently being used to improve bioavailability. This review discusses the different methods available for curcumin extraction from plant material, methods for the identification of curcumin in the resulting extracts, its beneficial effects on human health, and the encapsulation techniques into small colloidal systems that have been used over the past decade to deliver this compound.

Nanoemulsion curcumin injection showed significant anti-inflammatory activities on carrageenan-induced paw edema in Sprague-Dawley rats

Medicinal plants are candidates for the discovery of potential new anti-inflammatory agents. Curcumin is the active compound found in turmeric root, which has high anti-inflammatory activity. One of the limitations of curcumin as a therapeutic agent is its low solubility in water and extensive first-pass effect metabolism. The aim of this study was to formulate curcumin nanoemulsion for parenteral injection. We prepared curcumin nanoemulsions with a homogenizer using three surfactant concentrations (1.8%; 2.4%; and 3%) and two curcumin concentrations (1% and 3%). Formulas were evaluated for droplet diameter, polydispersity index, zeta potential, viscosity, pH, entrapment efficiency (EE), osmolality, sterility, and morphology. The nanoemulsion containing 1% curcumin and 3% surfactant (F3) demonstrated good stability. Curcumin nanoemulsions at 20 and 40 mg/kg doses showed anti-inflammatory activity on carrageenan-induced paw edema in male Sprague-Dawley rats. These two doses inhibited paw edema by 33% and 56% respectively at 5 h after carrageenan induction. Inhibition of edema volume by curcumin nanoemulsion at a dose of 40 mg/kg did not show a significant difference (P > 0.05) compared to the activity of the standard drug ketorolac at a dose of 2.7 mg/kg. We conclude that curcumin nanoemulsion has anti-inflammatory activity and can be a promising anti-inflammatory agent.

Fabrication and characterization of nanoemulsions for encapsulation and delivery of vitexin: antioxidant activity, storage stability and in vitro digestibility

BACKGROUND

Nanoemulsions were prepared as an encapsulation and delivery system for vitexin, a poorly water-soluble antioxidant. This study evaluated how the type and concentration of the dispersed oil phase and vitexin loading impacted droplet characteristics and nanoemulsion stability. The influences of storage temperature on antioxidant activity and in vitro gastrointestinal digestion on nanoemulsion stability were also investigated.

RESULTS

Nanoemulsions prepared at different dispersed oil concentrations showed diverse characteristics and stability. Highest stability against droplet aggregation and phase separation with small oil droplets (< 150 nm) was observed for nanoemulsions prepared using 300 g kg^-1 medium-chain triglyceride oil. These nanoemulsions are able to entrap and deliver vitexin with high encapsulation efficiency (88-90%) with no significant effect on emulsion stability. Vitexin-loaded nanoemulsions were stable during storage when refrigerated (4 °C) and at room temperature (25 °C) for up to 45 days with no effect on their antioxidant activity. Significantly delayed lipolysis rate and decreased extent of lipid digestion were observed in vitexin-loaded nanoemulsions.

CONCLUSIONS

Stable vitexin-loaded nanoemulsions were successfully produced by high-pressure homogenization using a mixture of Tween 80 and lecithin as emulsifiers. Vitexin-loaded nanoemulsions stabilized with a mixture of these two emulsifiers were effective in retaining antioxidant activity during storage and protecting vitexin from changes during gastrointestinal digestion. Our results suggested that nanoemulsions were effective vitexin delivery systems for food applications. © 2022 Society of Chemical Industry.

Designing and characterization of curcumin-loaded nanotechnological dressings: A promising platform for skin burn treatment

Burns affect the skin and appendages, impair their function, and become favorable regions for bacterial infections. Owing to time-consuming and costly treatments, burns have been considered a public health problem. The limitations of the treatments used for burns have motivated the search for more efficient alternatives. Curcumin has several potential properties such as anti-inflammatory, healing, and antimicrobial activities. However, this compound is unstable and has low bioavailability. Therefore, nanotechnology could offer a solution for its application. This study aimed to develop and characterize dressings (or gauzes) impregnated with curcumin nanoemulsions that were prepared using two different techniques as a promising platform for skin burn treatment. In addition, the effect of cationization on curcumin release from the gauze was evaluated. Nanoemulsions were successfully prepared using two methods, ultrasound and a high-pressure homogenizer, with sizes of 135 nm and 144.55 nm, respectively. These nanoemulsions exhibited a low polydispersity index, adequate zeta potential, high encapsulation efficiency, and stability for up to 120 d. In vitro assays demonstrated a controlled release of curcumin between 2 and 240 h. No cytotoxicity was observed at concentrations of curcumin up to 75 µg/mL, and cell proliferation was observed. The incorporation of nanoemulsions in the gauze was successfully achieved, and the evaluation of curcumin release showed a faster release from cationized gauzes, whereas the non-cationized gauze promoted a more constant release.

Parenteral Lipid-Based Nanoparticles for CNS Disorders: Integrating Various Facets of Preclinical Evaluation towards More Effective Clinical Translation

Contemporary trends in combinatorial chemistry and the design of pharmaceuticals targeting brain disorders have favored the development of drug candidates with increased lipophilicity and poorer water solubility, with the expected improvement in delivery across the blood-brain barrier (BBB). The growing availability of innovative excipients/ligands allowing improved brain targeting and controlled drug release makes the lipid nanocarriers a reasonable choice to overcome the factors impeding drug delivery through the BBB. However, a wide variety of methods, study designs and experimental conditions utilized in the literature hinder their systematic comparison, and thus slows the advances in brain-targeting by lipid-based nanoparticles. This review provides an overview of the methods most commonly utilized during the preclinical testing of liposomes, nanoemulsions, solid lipid nanoparticles and nanostructured lipid carriers intended for the treatment of various CNS disorders via the parenteral route. In order to fully elucidate the structure, stability, safety profiles, biodistribution, metabolism, pharmacokinetics and immunological effects of such lipid-based nanoparticles, a transdisciplinary approach to preclinical characterization is mandatory, covering a comprehensive set of physical, chemical, in vitro and in vivo biological testing.

The Impact of the Oil Phase Selection on Physicochemical Properties, Long-Term Stability, In Vitro Performance and Injectability of Curcumin-Loaded PEGylated Nanoemulsions

A nanotechnology-based approach to drug delivery presents one of the biggest trends in biomedical science that can provide increased active concentration, bioavailability, and safety compared to conventional drug-delivery systems. Nanoemulsions stand out amongst other nanocarriers for being biodegradable, biocompatible, and relatively easy to manufacture. For improved drug-delivery properties, longer circulation for the nanoemulsion droplets should be provided, to allow the active to reach the target site. One of the strategies used for this purpose is PEGylation. The aim of this research was assessing the impact of the oil phase selection, soybean or fish oil mixtures with medium chain triglycerides, on the physicochemical characteristics and injectability of curcumin-loaded PEGylated nanoemulsions. Electron paramagnetic resonance spectroscopy demonstrated the structural impact of the oil phase on the stabilizing layer of nanoemulsions, with a more pronounced stabilizing effect of curcumin observed in the fish oil nanoemulsion compared to the soybean oil one. The design of the experiment study, employed to simultaneously assess the impact of the oil phase, different PEGylated phospholipids and their concentrations, as well as the presence of curcumin, showed that not only the investigated factors alone, but also their interactions, had a significant influence on the critical quality attributes of the PEGylated nanoemulsions. Detailed physicochemical characterization of the NEs found all formulations were appropriate for parenteral administration and remained stable during two years of storage, with the preserved antioxidant activity demonstrated by DPPH and FRAP assays. In vitro release studies showed a more pronounced release of curcumin from the fish oil NEs compared to that from the soybean oil ones. The innovative in vitro injectability assessment, designed to mimic intravenous application, proved that all formulations tested in selected experimental setting could be employed in prospective in vivo studies. Overall, the current study shows the importance of oil phase selection when formulating PEGylated nanoemulsions.