Cetyltrimethylammonium bromide-nanocrystalline cellulose (CTAB-NCC) based microemulsions for enhancement of topical delivery of curcumin

High internal phase Pickering emulsion stabilized by thermally treated quinoa protein isolate: Improved stability and bioaccessibility of curcumin and astaxanthin

High internal phase Pickering emulsions (HIPPEs) were stabilized by thermally treated quinoa protein isolate (QPI), including atmospheric pressure boiling (AB), high pressure boiling (HPB), and baking (B), respectively, for the encapsulation of curcumin (CUR) and astaxanthin (AST) to retard its degradation during storage and improve their bioaccessibility. The QPI dispersion was sonicated to generate nanoparticles for the production of HIPPEs. Thermal treatments caused the reduction in the particle size and increased water contact angle compared to the control QPI nanoparticles, and further improving the emulsion properties of QPI. The microstructure results further supported the nature of oil-in-water of HIPPEs stabilized by QPI nanoparticles by showing that the nanoparticles formed a tight interfacial film and closely coated the surface of oil droplets. Thermal treatment reduced the droplet size by approximately 11%, 15%, and 3% for HIPPEs stabilized by AB-QPI, HPB-QPI, and B-QPI, respectively, compared to those of control QPI, which effectively improved the emulsion's viscoelasticity and storage stability. Retention rate and bioaccessibility of CUR and AST in HIPPEs were improved compared to the encapsulation by corn oil, showing HPB-QPI > AB-QPI > B-QPI > control QPI. HIPPEs stabilized by thermally treated QPI-protected lipophilic bioactive compounds and were beneficial for the advancement of functional foods based on QPI. PRACTICAL APPLICATION: The emulsifying properties of QPI nanoparticles were significantly improved after thermal treatment. High internal phase Pickering emulsion stabilized by thermally treated QPI nanoparticles significantly improved the stability and bioaccessibility of curcumin and astaxanthin. It provides a theoretical basis for utilizing thermally treated QPI nanoparticles as emulsifiers in delivery systems, broadening the development of curcumin and astaxanthin in the food and pharmaceutical fields.

Ultrasound-assisted preparation of shikonin-loaded emulsions for the treatment of bacterial infections

Bacteria can encapsulate themselves in a self-generated matrix of hydrated extracellular polymeric substances such as polysaccharides, proteins, and nucleic acids, thereby forming bacterial biofilm infections. These biofilms are drug resistant and will diminish the efficacy of antimicrobial agents, rendering treatment of such infections challenging. Herein, an innovative strategy is proposed to synergistically degrade bacterial biofilms and eradicate the entrapped bacteria through integrating α-amylase (α-Amy), shikonin (SK) and epigallocatechin gallate (EGCG) within an emulsion. The natural protein α-Amy is deployed to enzymatically hydrolyze the polysaccharide of biofilms. Due to the amphipilic properties of α-Amy and the cross-linking capability of EGCG, the formed α-Amy/SK@EGCG emulsion possess high stability. SK was encapsulated within the emulsion through ultrasound-assisted assembly, targeting to treat bacterial infection after biofilm degradation. In vitro and in vivo experiments demonstrate that the polyphenol-protein stabilized emulsion loaded with antibacterial SK achieves profound penetration into the biofilms due to the extracellular polysaccharide hydrolysis mediated by α-Amy. As a result, the α-Amy/SK@EGCG emulsion can significantly alleviate inflammation symptoms and accelerate the healing process of biofilm-infected wounds. This study provides a promising therapeutic strategy for the development of novel materials aimed for the enhanced treatment of bacterial biofilm infections.

Preparation, characterization and antibacterial investigation of water-soluble curcumin-chitooligosaccharide complexes

Curcumin has a wide range of application prospects, with various bioactivities in the food industry and in the biomedical field. However, curcumin has poor water solubility and is sensitive to pH, light and temperature. In this study, curcumin-chitooligosaccharide (CUR-COS) complexes were prepared via mechanochemical methods, and the CUR-COS complex was more soluble after freeze-drying (up to 862-fold greater than that of curcumin). The complex was characterized by SEM, XRD, FT-IR and thermal analysis, and its stability against pH, light and thermal treatment was evaluated. COSs could serve as carriers for curcumin delivery. Additionally, the antibacterial activity of the formed complex was determined. As a result, CUR-COS exhibited significantly better water solubility, enhanced stability, and stronger antibacterial properties than did pure CUR, offering a promising pathway for the extensive application of lipophilic natural products in foods, especially water-based products.

3D bioprinted poly(lactic acid) scaffolds infused with curcumin-loaded nanostructured lipid carriers: a promising approach for skin regeneration

Nanotechnology and 3D bioprinted scaffolds are revolutionizing the field of wound healing and skin regeneration. By facilitating proper cellular movement and providing a customizable structure that replicates the extracellular matrix, such technologies not only expedite the healing process but also ensure the seamless integration of new skin layers, enhancing tissue repair and promoting overall cell growth. This study centres on the creation and assessment of a nanostructured lipid carrier containing curcumin (CNLC), which is integrated into a 3D bioprinted PLA scaffold system. The goal is to investigate its potential as a vehicle for delivering poorly soluble curcumin for enhanced wound healing. The developed CNLC exhibited an oval morphology and average particle size of 292 nm. The entrapment efficiency (EE) was 81.37 ± 0.85%, and the drug loading capacity was 6.59 ± 1.61%. CNLC was then integrated into PLA-based 3D bioprinted scaffolds, and physicochemical analyses were conducted to evaluate their properties. Cell viability studies carried out using fibroblast cells demonstrated that the PLA/CNLC scaffolds are non-cytotoxic. In vivo experiments showed that the PLA/CNLC scaffolds exhibited complete wound contraction and closure of full-thickness wounds within a period of 21 days. The findings confirmed the scaffold's capacity as a tool for accelerating wound healing. The research emphasises the need for using biomimetic 3D printed scaffold materials and the promise of nanobiotechnology in enhancing treatment efficacy.

Understanding Microemulsions and Nanoemulsions in (Trans)Dermal Delivery

Continuously explored in pharmaceuticals, microemulsions and nanoemulsions offer drug delivery opportunities that are too significant to ignore, namely safe delivery of clinically relevant drug doses across biological membranes. Their effectiveness as drug vehicles in mucosal and (trans)dermal delivery is evident from the volume of published literature. Commonly, their ability to enhance skin permeation is attributed to dispersion size, a characteristic closely related to solubilization capacity. However, the literature falls short on distinctions between microemulsions and nanoemulsions for definitions, behavior, or specific differences in their mechanisms of action in (trans)dermal delivery. The focus is typically on surfactant/cosurfactant ratio and droplet size but the role of mesostructures or the effect of cosolvent (Csol), oil (O) or water (W) on permeation profile remain poorly explained. Towards a deeper understanding of these vehicles in (trans)dermal drug delivery, this review begins with their conceptual and practical distinctions before delving into the published works for less obvious but potentially important underlying mechanisms; notably composition and the competitive positioning of system constituents in the resulting microstructures and subsequent effect(s) these may have on skin structures and drug permeability. For practical purposes, this review focuses on formulation systems based on ternary diagrams with commonly accepted non-ionic surfactants, cosurfactants, cosolvents, and oils used in pharmaceutical applications.

In Vitro and In Vivo Evaluation of Electrospun PVA Nanofiber Containing ZnO/Curcumin for Wound Healing Application

The development of biocompatible wound dressings containing therapeutic agents to accelerate wound healing is an interesting field of study in biomedical sciences. Polyvinyl alcohol (PVA) nanofibers were loaded with zinc oxide nanoparticles (ZnO NPs) and curcumin (Cur) through electrospinning. The dressings were characterized by SEM and XRD and FTIR. The antioxidant, antibacterial, and cytotoxic activities Cur/ZnO/PVA nano dressing were evaluated using DPPH radical scavenging assay, disc diffusion method, and MTT assay, respectively. Cur/ZnO/PVA nano dressing showed sustained Cur release about 19.7% and 61.1% after 8h and 168h, respectively. Cur/ZnO NPs/PVA mixture had higher antioxidant potential than PVA, ZnO NPs, and Cur. The dressing showed a good antibacterial effect. The in vivo wound healing effect of different types of prepared dressings, including PVA, Cur/PVA, Cur/ZnO/PVA, and ZnO/ PVA nanofibers, was also investigated. PVA dressing containing Cur/ZnO NPs resulted in the highest increase of wound contraction in rats. The assembly of Cur and ZnO NPs on PVA nanofibers could propose as an effective delivery method to improve the wound healing process. The investigated wound dressing could be commercialized and used on a large scale after proper further studies, including clinical trials.

Encapsulation of sunflower and flaxseed oils using Opuntia (Cactaceae) mucilage as a core-shell material through coacervation methods: A study on formulation, characterization, and in vitro digestion

Sunflower oil (SFO) and Flaxseed oil (FSO) were microencapsulated using simple and complex coacervation techniques with Opuntia (Cactaceae) mucilage (Mu) and with a combination of Mu with chitosan (Chit). The encapsulation efficiency (EE) of SFO and FSO in emulsions using Mu/Chit shells was 96.7% and 97.4%, respectively. Morphological studies indicated successful entrapment of oils in core shells with particle sizes ranging from 1396 ± 42.4 to 399.8 ± 42.3 nm. The thermogravimetric analyses demonstrated enhanced core protection with thermal stability noted for microcapsules regardless of encapsulation method. The stability of the microcapsules, during in vitro digestion was studied. The obtained results revealed that the microcapsules are intact in oral conditions and have a slow release of oil over stomach digestion and rapid release in the small intestine. The results showed that Mu and Mu/Chit coacervates can be used as effective carrier systems to encapsulate sensitive ingredients and functional oils.

Improving curcumin bioavailability: Targeted delivery of curcumin and loading systems in intestinal inflammation

Curcumin is a natural food ingredient and has the potential to alleviate inflammation and combat cancer. The incidence of intestinal inflammation has been increasing and poses a severe risk to human health. Due to low absorption and bioavailability, curcumin's anti-inflammatory ability is ineffective. To improve the bioavailability of curcumin, descriptions of the intestinal barrier, signaling pathways, and transport mechanisms are reviewed. Blocking the signaling pathways lowers the number of inflammatory cytokines produced, which is the primary mechanism by which curcumin relieves inflammatory symptoms. The bioavailability of curcumin is not only related to physicochemical properties but also to the nature of the carrier material. Environmental indicators also have an impact on the improvement of curcumin bioavailability in applications. There is a need to develop multifunctional and more stable nanomaterial targeting systems to improve curcumin bioavailability and achieve better results in nanotechnology research and targeted inflammation therapy.

The potential of nanofibrillated cellulose from Hevea brasiliensis to produce films for bio-based packaging

Cellulose micro/nanofibril (MNFC) films are an interesting alternative to plastic-based films for application in biodegradable packaging. In this study, we aimed to produce and characterize MNFC films obtained from alkaline-pretreated rubberwood (Hevea brasiliensis) waste and Eucalyptus sp. commercial pulp. MNFC and films were evaluated regarding microstructure; crystallinity; stability; and physical, optical, mechanical, and barrier properties. A combined quality index (QI) was also calculated. Eucalyptus MNFC suspensions were more stable than H. brasiliensis. Both films had a hydrophobic surface (>90°) and high grease resistance (oil kit 12). H. brasiliensis films had lower transparency (26.4 %) and high crystallinity (∼89 %), while Eucalyptus films had lower permeability and higher mechanical strength. The QI of MNFC was 51 ± 5 for H. brasiliensis and 55 ± 4 for Eucalyptus, showing that both types of raw material have potential for application in the packaging industry and in the reinforcement of composites, as well as for high value-added applications in products made from special materials.

Folic acid-modified nanocrystalline cellulose for enhanced delivery and anti-cancer effects of crocin

Crocin is a carotenoid compound in saffron with anti-cancer properties. However, its therapeutic application is limited by its low absorption, bioavailability, and stability, which can be overcome through nanocarrier delivery systems. This study used surface-modified Nano-crystalline cellulose (NCC) to deliver crocin to cancer cells. NCC modified with CTAB were loaded with crocin and then conjugated with folic acid (NCF-CR-NPs). The synthesized nanoparticles (NPs) were characterized using FTIR, XRD, DLS, and FESEM. The crystallinity index of NCC was 66.64%, higher than microcrystalline cellulose (61.4%). The crocin loading and encapsulation efficiency in NCF-CR-NPs were evaluated. Toxicity testing by MTT assay showed that NCF-CR-NPs had higher toxicity against various cancer cell lines, including colon cancer HT-29 cells (IC50 ~ 11.6 μg/ml), compared to free crocin. Fluorescent staining, flow cytometry, and molecular analysis confirmed that NCF-CR-NPs induced apoptosis in HT-29 cells by increasing p53 and caspase 8 expression. The antioxidant capacity of NCF-CR-NPs was also evaluated using ABTS and DPPH radical scavenging assays. NCF-CR-NPs exhibited high free radical scavenging ability, with an IC50 of ~ 46.5 μg/ml for ABTS. In conclusion, this study demonstrates the potential of NCF-CR-NPs to deliver crocin to cancer cells effectively. The NPs exhibited enhanced anti-cancer and antioxidant activities compared to free crocin, making them a promising nanocarrier system for crocin-based cancer therapy.

Advanced 3D Electrospinning "Xspin" System: Fabrication of Bifiber Floating Oral Pharmaceutical Scaffolds for Controlled Drug Delivery

Electrospinning has become a widely used and efficient method for manufacturing nanofibers from diverse polymers. This study introduces an advanced electrospinning technique, Xspin - a multi-functional 3D printing platform coupled with electrospinning system, integrating a customised 3D printhead, MaGIC - Multi-channeled and Guided Inner Controlling printheads. The Xspin system represents a cutting-edge fusion of electrospinning and 3D printing technologies within the realm of pharmaceutical sciences and biomaterials. This innovative platform excels in the production of novel fiber with various materials and allows for the creation of highly customized fiber structures, a capability hitherto unattainable through conventional electrospinning methodologies. By integrating the benefits of electrospinning with the precision of 3D printing, the Xspin system offers enhanced control over the scaffold morphology and drug release kinetics. Herein, we fabricated a model floating pharmaceutical dosage for the dual delivery of curcumin and ritonavir and thoroughly characterized the product. Fourier transform infrared (FTIR) spectroscopy demonstrated that curcumin chemically reacted with the polymer during the Xspin process. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) confirmed the solid-state properties of the active pharmaceutical ingredient after Xspin processing. Scanning electron microscopy (SEM) revealed the surface morphology of the Xspin-produced fibers, confirming the presence of the bifiber structure. To optimize the quality and diameter control of the electrospun fibers, a design of experiment (DoE) approach based on quality by design (QbD) principles was utilized. The bifibers expanded to approximately 10-11 times their original size after freeze-drying and effectively entrapped 87% curcumin and 84% ritonavir. In vitro release studies demonstrated that the Xspin system released 35% more ritonavir than traditional pharmaceutical pills in 2 h, with curcumin showing complete release in pH 1.2 in 5 min, simulating stomach media. Furthermore, the absorption rate of curcumin was controlled by the characteristics of the linked polymer, which enables both drugs to be absorbed at the desired time. Additionally, multivariate statistical analyses (ANOVA, pareto chart, etc.) were conducted to gain better insights and understanding of the results such as discern statistical differences among the studied groups. Overall, the Xspin system shows significant potential for manufacturing nanofiber pharmaceutical dosages with precise drug release capabilities, offering new opportunities for controlled drug delivery applications.

The Nanotech Potential of Curcumin in Pharmaceuticals: An Overview

It is safe to use Curcumin as a cosmetic and therapeutic ingredient in pharmaceutical products. For the uses mentioned above and for fundamental research, it is essential to obtain pure Curcumin from plant sources. There is a requirement for effective extraction and purification techniques that adhere to green chemistry standards for efficiency improvement, process safety, and environmental friendliness. Several outstanding studies have looked into the extraction and purification of Curcumin. This review thoroughly covers the currently available curcumin extraction, synthesis, and transformation techniques. Additionally, Curcumin's poor solubility and low absorption in the human body have limited its potential for pharmaceutical use. However, recent developments in novel curcumin formulations utilizing nanotechnology delivery methods have provided new approaches to transport and maximize the human body's curcumin absorption efficiency. In this review, we explore the various curcumin nanoformulations and the potential medicinal uses of nano curcumin. Additionally, we review the necessary future research directions to recommend Curcumin as an excellent therapeutic candidate.

Preparation, in vitro and in vivo evaluation of a novel mitiglinide microemulsions

This study aimed to prepare an o/w mitiglinide microemulsion (MTGME) to improve the drug solubility and bioavailability. The formulation of o/w MTGME was optimized by the solubility study of drug, pseudo-ternary phase diagram and Box-Behnken design successively. MTGME was characterized by dynamic laser light scattering (DLS), zeta potential and transmission electron microscopy (TEM), moreover, the storage stability, pharmacodynamics and pharmacokinetics were investigated. The optimal prescription for MTGME consisted of Maisine 35-1 (oil), Cremophor EL (surfactant) and propylene glycol (PG, cosurfactant). MTGME with a spherical dimension of 58.1 ± 5.86 nm was stable when stored at 4 °C for 3 months. The blood glucose levers (BGL) of diabetic mice were uniformly and significantly decreased by intragastric (i.g.) administration of 1-4 mg/kg MTGME, in which BGL (i.g. 4 mg/kg MTGME) was reduced by 69% during 24 h. The pharmacokinetics study of MTGME (i.g., 20 mg/kg) in Wistar rats showed higher plasma drug concentration (Cmax, 2.9 folds), larger area under curve (AUC, 4.6 folds) and oral bioavailability than those of MTG suspensions. Generally, the MTGME (o/w) showed good effect on controlling hyperglycemia. Therefore, microemulsion can be used as an effective oral drug delivery system to improve the bioavailability of MTG.

Nanosizing of Lavender, Basil, and Clove Essential Oils into Microemulsions for Enhanced Antioxidant Potential and Antibacterial and Antibiofilm Activities

Plant essential oils (EOs) possess significant bioactivities (antibacterial and antioxidant) and can be substituted for potentially harmful synthetic preservatives in the food industry. However, limited water solubility, bioavailability, volatility, and stability limit their use. Therefore, the goal of this research was nanosizing lavender essential oil (LEO), basil essential oil (BEO), and clove essential oil (CEO) in a microemulsion (ME) to improve their physicochemical attributes and bioefficacy. Tween 80 and Transcutol P were utilized for construction of pseudoternary phase diagrams. It was observed that the concentration of EOs had a great impact on the physicochemical and biological properties of MEs. A spherical droplet of MEs with a diameter of less than 20 nm with a narrower size distribution (polydispersity index (PDI) = 0.10-0.27) and a ζ potential of -0.27 to -9.03 was observed. ME formulations were also evaluated for viscosity, conductivity, and the refractive index. Moreover, the impact of delivery systems on the antibacterial property of EOs was assessed by determining the zone of inhibition and minimum inhibitory concentration against two distinct pathogen classes (S. aureus and E. coli). Crystal violet assay was used to measure the growth and development of biofilms. According to bioefficacy assays, ME demonstrated more efficient antibacterial activity against microorganisms at concentrations lower than pure EOs. CEO ME had superior activity againstS. aureus and E. coli. Similarly, dose-dependent antioxidant capacity was noted for MEs. Consequently, nanosized EO formulations with improved physicochemical properties and enhanced bioactivities can be employed in the food processing sector as a preservation agent.

Microemulsion-Based Keratin-Chitosan Gel for Improvement of Skin Permeation/Retention and Activity of Curcumin

Curcumin (Cur) is a kind of polyphenol with a variety of topical pharmacological properties including antioxidant, analgesic and anti-inflammatory activities. However, its low water solubility and poor skin bioavailability limit its effectiveness. In the current study, we aimed to develop microemulsion-based keratin-chitosan gel for the improvement of the topical activity of Cur. The curcumin-loaded microemulsion (CME) was formulated and then loaded into the keratin-chitosan (KCS) gel to form the CME-KCS gel. The formulated CME-KCS gel was evaluated for its characterization, in vitro release, in vitro skin permeation and in vivo activity. The results showed that the developed CME-KCS gel had an orange-yellow and gel-like appearance. The particle size and zeta potential of the CME-KCS gel were 186.45 ± 0.75 nm and 9.42 ± 0.86 mV, respectively. The CME-KCS gel showed desirable viscoelasticity, spreadability, bioadhesion and controlled drug release, which was suitable for topical application. The in vitro skin permeation and retention study showed that the CME-KCS gel had better in vitro skin penetration than the Cur solution and achieved maximum skin drug retention (3.75 ± 0.24 μg/cm²). In vivo experimental results confirmed that the CME-KCS gel was more effective than curcumin-loaded microemulsion (Cur-ME) in analgesic and anti-inflammatory activities. In addition, the CME-KCS gel did not cause any erythema or edema based on a mice skin irritation test. These findings indicated that the developed CME-KCS gel could improve the skin penetration and retention of Cur and could become a promising formulation for topical delivery to treat local diseases.

Effect of different pre-treatments on the redispersion capacity of spray-dried microfibrillated cellulose: Elaboration and characterization of biofilms

This study aimed to evaluate the influence of the addition of the cationic surfactant cetyltrimethylammonium bromide (CTAB) in microfibrillated cellulose (MFC/CNFs) suspensions submitted to different pretreatments to produce redispersible spray-dried (SD) MFC/CNFs. Suspensions pretreated with 5 % and 10 % sodium silicate and oxidized with 2,2,6,6,-tetramethylpiperidinyl-1-oxyl (TEMPO) were modified with CTAB surfactant and subsequently dried by SD. The SD-MFC/CNFs aggregates were redispersed by ultrasound to produce cellulosic films by the casting method. In summary, the results demonstrated that the addition of CTAB surfactant to the TEMPO-oxidized suspension was critical to achieving the most effective redispersion. The experimental results obtained using micrographs, optical (UV-Vis), mechanical, water vapor barrier properties, and the quality index confirmed that the addition of CTAB to the TEMPO-oxidized suspension favored the redispersion of spray-dried aggregates, development of cellulosic films with attractive properties, offering possibilities for the elaboration of new products, for example, in the production of bionanocomposites with higher mechanical performance. This research brings interesting insights into the redispersion and application of SD-MFC/CNFs aggregates, strengthening the commercialization of MFC/CNFs for industrial use.

Exploring the Versatility of Microemulsions in Cutaneous Drug Delivery: Opportunities and Challenges

Microemulsions are novel drug delivery systems that have garnered significant attention in the pharmaceutical research field. These systems possess several desirable characteristics, such as transparency and thermodynamic stability, which make them suitable for delivering both hydrophilic and hydrophobic drugs. In this comprehensive review, we aim to explore different aspects related to the formulation, characterization, and applications of microemulsions, with a particular emphasis on their potential for cutaneous drug delivery. Microemulsions have shown great promise in overcoming bioavailability concerns and enabling sustained drug delivery. Thus, it is crucial to have a thorough understanding of their formulation and characterization in order to optimize their effectiveness and safety. This review will delve into the different types of microemulsions, their composition, and the factors that affect their stability. Furthermore, the potential of microemulsions as drug delivery systems for skin applications will be discussed. Overall, this review will provide valuable insights into the advantages of microemulsions as drug delivery systems and their potential for improving cutaneous drug delivery.

Redox-responsive microemulsion: Fabrication and application to curcumin encapsulation

HYPOTHESIS

Stimulus-responsive microemulsions have aroused significant attention because of their versatile and reversible switchability between stable and unstable states. However, most stimuli-responsive microemulsions are based on stimuli-responsive surfactants. We posit that the change in the hydrophilicity of a selenium-containing alcohol triggered by a mild redox reaction could also influence the stability of microemulsions and provide a new nanoplatform for the delivery of bioactive substances.

EXPERIMENTS

A selenium-containing diol (3,3'-selenobis(propan-1-ol), PSeP) was designed and used as a co-surfactant in a microemulsion with ethoxylated hydrogenated castor oil (HCO40), diethylene glycol monohexyl ether (DGME), 2-n-octyl-1-dodecanol (ODD) and water. The redox-induced transition in PSeP was characterized by ¹H NMR, ⁷⁷Se NMR, and MS. The redox-responsiveness of the ODD/HCO40/DGME/PSeP/water microemulsion was investigated through determination of a pseudo-ternary phase diagram, analysis by dynamic light scattering, and electrical conductivity, and its encapsulation performance was evaluated by determination of the solubility, stability, antioxidant activity, and skin penetrability of encapsulated curcumin.

FINDINGS

The redox conversion of PSeP enabled efficient switching of ODD/HCO40/DGME/PSeP/water microemulsions. Addition of oxidant (H₂O₂), oxidized PSeP into more hydrophilic PSeP-Ox (selenoxide), disrupting the emulsifying capacity of the combination of HCO40/DGME/PSeP, markedly reducing the monophasic microemulsion region in the phase diagram, and inducing phase separation in some formulations. Addition of reductant (N₂H₄·H₂O), reduced PSeP-Ox and restored the emulsifying capacity of the combination of HCO40/DGME/PSeP. In addition, PSeP-based microemulsions can significantly enhance the solubility in oil (by 23 times), stability, antioxidant capacity (DPPH∙ radical scavenging by 91.74 %), and skin penetrability of curcumin, showing clear potential for encapsulation and delivery of curcumin and other bioactive substances.

Recent Development of Nanomaterials for Transdermal Drug Delivery

Nano-engineered medical products first appeared in the last decade. The current research in this area focuses on developing safe drugs with minimal adverse effects associated with the pharmacologically active cargo. Transdermal drug delivery, an alternative to oral administration, offers patient convenience, avoids first-pass hepatic metabolism, provides local targeting, and reduces effective drug toxicities. Nanomaterials provide alternatives to conventional transdermal drug delivery including patches, gels, sprays, and lotions, but it is crucial to understand the transport mechanisms involved. This article reviews the recent research trends in transdermal drug delivery and emphasizes the mechanisms and nano-formulations currently in vogue.

An Overview of Nanoemulgels for Bioavailability Enhancement in Inflammatory Conditions via Topical Delivery

The anti-inflammatory drugs that are generally available possess the disadvantage of hydrophobicity, which leads to poor permeability and erratic bioavailability. Nanoemulgels (NEGs) are novel drug delivery systems that aim to improve the solubility and permeability of drugs across the biological membrane. The nano-sized droplets in the nanoemulsion enhance the permeation of the formulation, along with surfactants and co-surfactants that act as permeation enhancers and can further improve permeability. The hydrogel component of NEG helps to increase the viscosity and spreadability of the formulation, making it ideal for topical application. Moreover, oils that have anti-inflammatory properties, such as eucalyptus oil, emu oil and clove oil, are used as oil phases in the preparation of the nanoemulsion, which shows a synergistic effect with active moiety and enhances its overall therapeutic profile. This leads to the creation of hydrophobic drugs that possess enhanced pharmacokinetic and pharmacodynamic properties, and simultaneously avoid systemic side effects in individuals with external inflammatory disorders. The nanoemulsion's effective spreadability, ease of application, non-invasive administration, and subsequent ability to achieve patient compliance make it more suitable for topical application in the combat of many inflammatory disorders, such as dermatitis, psoriasis, rheumatoid arthritis, osteoarthritis and so on. Although the large-scale practical application of NEG is limited due to problems regarding its scalability and thermodynamic instability, which arise from the use of high-energy approaches during the production of the nanoemulsion, these can be resolved by the advancement of an alternative nanoemulsification technique. Considering the potential advantages and long-term benefits of NEGs, the authors of this paper have compiled a review that elaborates the potential significance of utilizing nanoemulgels in a topical delivery system for anti-inflammatory drugs.

Curcumin-Loaded Bioactive Polymer Composite Film of PVA/Gelatin/Tannic Acid Downregulates the Pro-inflammatory Cytokines to Expedite Healing of Full-Thickness Wounds

Curcumin (Cur) entrapped poly(vinyl alcohol) (PVA)/gelatin composite films were prepared by cross-linking with tannic acid (TA) as bioactive dressings for rapid wound closure. Films were evaluated for mechanical strength, swelling index, water vapor transmission rate (WVTR), film solubility, and in-vitro drug release studies. SEM revealed uniform and smooth surfaces of blank (PG9) and Cur-loaded composite films (PGC4). PGC4 exhibited excellent mechanical strength (tensile strength (TS) and Young's modulus (YM) were 32.83 and 0.55 MPa, respectively), swelling ability (600-800% at pH 5.4, 7.4, and 9), WVTR (2003 ± 26), and film solubility (27.06 ± 2.0). Sustained release (81%) of the encapsulated payload was also observed for 72 h. The antioxidant activity determined by DPPH free radical scavenging showed that the PGC4 possessed strong % inhibition. The PGC4 formulation displayed higher antibacterial potential against S. aureus (14.55 mm zone of inhibition) and E. coli (13.00 mm zone of inhibition) compared to blank and positive control by the agar well diffusion method. An in-vivo wound healing study was carried out on rats using a full-thickness excisional wound model. Wounds treated with PGC4 showed very rapid healing about 93% in just 10 days post wounding as compared to 82.75% by Cur cream and 80.90% by PG9. Furthermore, histopathological studies showed ordered collagen deposition and angiogenesis along with fibroblast formation. PGC4 also exerted a strong anti-inflammatory effect by downregulating the expression of pro-inflammatory cytokines (TNF-α and IL-6 were lowered by 76% and 68% as compared to the untreated group, respectively). Therefore, Cur-loaded composite films can be an ideal delivery system for effective wound healing.

Curcumin-loaded microemulsion: formulation, characterization, and in vitro skin penetration

OBJECTIVE

Formulation of curcumin in a microemulsion with a high loading capacity and that favors its penetration into the skin.

SIGNIFICANCE

Take advantage of the properties of microemulsions to promote the penetration of curcumin into the skin, with the aim of enhancing its therapeutic effects.

METHODS

Curcumin was formulated in microemulsions based on oleic acid (oil phase), Tween® 80 (surfactant), and Transcutol^® HP (cosurfactant). The microemulsion formation area was mapped by constructing pseudo-ternary diagrams for surfactant:co-surfactant ratios 1:1, 1:2, and 2:1. Microemulsions were characterized through measurements of specific weight, refractive index, conductivity, viscosity, droplet size, and in vitro skin permeation studies.

RESULTS

Nine microemulsions were prepared and characterized, showing clear, stable formulations with globule size dependent on the proportion of the components. The microemulsion with the highest loading capacity (60 mg/mL), based on Tween^® 80, Transcutol^® HP, oleic acid, and water (40:40:10:10) was able to penetrate the viable epidermis, finding a total amount of curcumin in the receptor medium at 24 h of 10.17 ± 9.7 µg/cm². The distribution of curcumin in the skin, visualized by confocal laser scanning microscopy, showed that the maximum amount was located between 20 and 30 µm.

CONCLUSION

The inclusion of curcumin in a microemulsion allows its passage into and through the skin. The localization of curcumin, especially in the viable epidermis, would be important for those cases where local conditions are sought to be treated.

Wound-Healing Effects of Curcumin and Its Nanoformulations: A Comprehensive Review

Wound healing is an intricate process of tissue repair or remodeling that occurs in response to injury. Plants and plant-derived bioactive constituents are well explored in the treatment of various types of wounds. Curcumin is a natural polyphenolic substance that has been used since ancient times in Ayurveda for its healing properties, as it reduces inflammation and acts on several healing stages. Several research studies for curcumin delivery at the wound site reported the effectiveness of curcumin in eradicating reactive oxygen species and its ability to enhance the deposition of collagen, granulation tissue formation, and finally, expedite wound contraction. Curcumin has been widely investigated for its wound healing potential but its lower solubility and rapid metabolism, in addition to its shorter plasma half-life, have limited its applications in wound healing. As nanotechnology has proven to be an effective technique to accelerate wound healing by stimulating appropriate mobility through various healing phases, curcumin-loaded nanocarriers are used for targeted delivery at the wound sites. This review highlights the potential of curcumin and its nanoformulations, such as liposomes, nanoparticles, and nano-emulsions, etc. in wound healing. This paper emphasizes the numerous biomedical applications of curcumin which collectively prepare a base for its antibiofilm and wound-healing action.

Cellulose nanocrystals based delivery vehicles for anticancer agent curcumin

Cancer is a complex disease that starts with genetic alterations and mutations in healthy cells. The past decade has witnessed a huge demand for new biocompatibility and high-performance intelligent drug delivery systems. Curcumin (CUR) is a bioactive stimulant with numerous medical benefits. However, because of its hydrophobic nature, it has low bioavailability. The utilization of many biobased materials has been found to improve the loading of hydrophobic drugs. Cellulose nanocrystals (CNCs) with exceptional qualities and a wide range of applications, feature strong hydrophilicity and lipophilicity, great emulsification stability, high crystallinity and outstanding mechanical attributes. In this review, numerous CNCs-based composites have been evaluated for involvement in the controlled release of CUR. The first part of the review deals with recent advancements in the extraction of CNCs from lignocellulose biomass. The second elaborates some recent developments in the post-processing of CNCs in conjunction with other materials like natural polymers, synthetic polymers, β-CD, and surfactants for CUR loading/encapsulation and controlled release. Furthermore, numerous CUR drug delivery systems, challenges, and techniques for effective loading/encapsulation of CUR on CNCs-based composites have been presented. Finally, conclusions and future outlooks are also explored.

Curcumin and Related Compounds in Cancer Cells: New Avenues for Old Molecules

Curcumin and related compounds are known for the large spectrum of activities. The chemical features of these compounds are important for their biological effects with a key role for the thiol-reactive α−β unsaturated carbonyl groups. Curcumin derivatives may overcome the limitation of the bioavailability of the parent compound, while maintaining the key chemical features responsible for biological activities. Curcumin and related compounds show anti-viral, anti-fungal, anti-microbial and anti-tumor activities. The therapeutic effects of curcumin, used as a supplement in cancer therapy, have been documented in various cancer types, in which inhibition of cell growth and survival pathways, induction of apoptosis and other cell death pathways have been reported. Curcumin-induced apoptosis has been linked both to the intrinsic and extrinsic apoptotic pathways. Necroptosis has also been involved in curcumin-induced toxicity. Among curcumin-induced effects, ferroptosis has also been described. The mechanism of curcumin toxicity can be triggered by reactive oxygen species-mediated endoplasmic reticulum stress. Curcumin targets have been identified in the context of the ubiquitin-proteasome system with evidence of inhibition of the proteasome proteolytic activities and cellular deubiquitinases. Curcumin has recently been shown to act on the tumor microenvironment with effects on cancer-associated fibroblasts and immune cells. The related product caffeic acid phenethyl ester has shown promising preclinical results with an effect on the inflammatory microenvironment. Here, we review the mechanisms underlying curcumin and derivatives toxicity towards cancer cells with particular emphasis on cell death pathways and the ubiquitin-proteasome system.

Evaluation of Hydrophilic and Hydrophobic Silica Particles on the Release Kinetics of Essential Oil Pickering Emulsions

Colloidal particle-stabilized emulsions have recently gained increasing interest as delivery systems for essential oils. Despite the use of silica particles in food and pharmaceutical applications, the formation and release of hydrophilic and hydrophobic silica particle-stabilized emulsions are still not well studied. Thus, in this study, the structures of hydrophilic (A200, A380, 244FP, and 3150) and hydrophobic (R202 and R106) silica were deeply characterized using the solid state, contact angle, and other properties that could affect the formation of emulsions. Following that, Mosla chinensis essential oil emulsions were stabilized with different types of silica, and their characteristics, particularly their release behavior, were studied. Fick's second law was used to investigate the mechanism of release. Additionally, six mathematical models were employed to assess the experimental data of release: zero-order, first-order, Higuchi, Hixson-Crowell, Peppas, and Page models. The release mechanism of essential oils demonstrated that diffusion was the dominant mechanism, and the fitting results for the release kinetics confirmed that the release profiles were governed by the Higuchi model. The contact angle and specific surface area were the key properties that affect the release of essential oils from emulsions. Hydrophilic A200 was found to be capable of delivering essential oils more efficiently, and silica particles could be extended to achieve the controlled release of bioactives. This study showed that understanding the impact of silica particles on the release behavior provided the basis for modulating and mapping material properties to optimize the performance of emulsion products.

Nanocellulose, a versatile platform: From the delivery of active molecules to tissue engineering applications

Nanocellulose, a biopolymer, has received wide attention from researchers owing to its superior physicochemical properties, such as high mechanical strength, low density, biodegradability, and biocompatibility. Nanocellulose can be extracted from wide range of sources, including plants, bacteria, and algae. Depending on the extraction process and dimensions (diameter and length), they are categorized into three main types: cellulose nanocrystals (CNCs), cellulose nanofibrils (CNFs), and bacterial nanocellulose (BNC). CNCs are a highly crystalline and needle-like structure, whereas CNFs have both amorphous and crystalline regions in their network. BNC is the purest form of nanocellulose. The nanocellulose properties can be tuned by chemical functionalization, which increases its applicability in biomedical applications. This review highlights the fabrication of different surface-modified nanocellulose to deliver active molecules, such as drugs, proteins, and plasmids. Nanocellulose-mediated delivery of active molecules is profoundly affected by its topographical structure and the interaction between the loaded molecules and nanocellulose. The applications of nanocellulose and its composites in tissue engineering have been discussed. Finally, the review is concluded with further opportunities and challenges in nanocellulose-mediated delivery of active molecules.

Anti-Inflammatory Effects of Curcumin in the Inflammatory Diseases: Status, Limitations and Countermeasures

Curcumin is a natural compound with great potential for disease treatment. A large number of studies have proved that curcumin has a variety of biological activities, among which anti-inflammatory effect is a significant feature of it. Inflammation is a complex and pervasive physiological and pathological process. The physiological and pathological mechanisms of inflammatory bowel disease, psoriasis, atherosclerosis, COVID-19 and other research focus diseases are not clear yet, and they are considered to be related to inflammation. The anti-inflammatory effect of curcumin can effectively improve the symptoms of these diseases and is expected to be a candidate drug for the treatment of related diseases. This paper mainly reviews the anti-inflammatory effect of curcumin, the inflammatory pathological mechanism of related diseases, the regulatory effect of curcumin on these, and the latest research results on the improvement of curcumin pharmacokinetics. It is beneficial to the further study of curcumin and provides new ideas and insights for the development of curcumin anti-inflammatory preparations.

Novel Gel Microemulsion as Topical Drug Delivery System for Curcumin in Dermatocosmetics

Gel microemulsion combines the advantages of the microemulsion, which can encapsulate, protect and deliver large quantities of active ingredients, and the gel, which is so appreciated in the cosmetic industry. This study aimed to develop and characterize new gel microemulsions suitable for topical cosmetic applications, using grape seed oil as the oily phase, which is often employed in pharmaceuticals, especially in cosmetics. The optimized microemulsion was formulated using Tween 80 and Plurol^® Diisostearique CG as a surfactant mix and ethanol as a co-solvent. Three different water-soluble polymers were selected in order to increase the viscosity of the microemulsion: Carbopol^® 980 NF, chitosan, and sodium hyaluronate salt. All used ingredients are safe, biocompatible and biodegradable. Curcumin was chosen as a model drug. The obtained systems were physico-chemically characterized by means of electrical conductivity, dynamic light scattering, polarized microscopy and rheometric measurements. Evaluation of the cytotoxicity was accomplished by MTT assay. In the final phase of the study, the release behavior of Curcumin from the optimized microemulsion and two gel microemulsions was evaluated. Additionally, mathematical models were applied to establish the kinetic release mechanism. The obtained gel microemulsions could be effective systems for incorporation and controlled release of the hydrophobic active ingredients.