Formulation of tocopherol nanocarriers andin vitrodelivery into human skin

The Potential Application of Nanocarriers in Delivering Topical Antioxidants

The imbalance in the production of reactive oxygen species (ROS) with endogenous antioxidant capacity leads to oxidative stress, which drives many disorders, especially in the skin. In such conditions, supplementing exogenous antioxidants may help the body prevent the negative effect of ROS. However, the skin, as the outermost barrier of the body, provides a perfect barricade, making the antioxidant delivery complicated. Several strategies have been developed to enhance the penetration of antioxidants through the skin, one of which is nanotechnology. This review focuses on utilizing several nanocarrier systems, including nanoemulsions, liposomes, solid lipid nanoparticles (SLNs), nanostructured lipid carriers (NLCs), and polymeric nanoparticles, for transporting antioxidants into the skin. We also reveal ROS formation in the skin and the role of antioxidant therapy, as well as the natural sources of antioxidants. Furthermore, we discuss the clinical application of topical antioxidant therapy concomitantly with the current status of using nanotechnology to deliver topical antioxidants. This review will accelerate the advancement of topical antioxidant therapy.

Exercise-induced local sweating: Greater reduction in women than men with sunscreen use

Sunscreens may affect thermoregulation and sweating during exercise in warm climates. In this study, we compared the effects of three sunscreens on local sweating rate (LSR) during exercise under controlled conditions (32°C, relative humidity 55%). Fifteen subjects (8 men, 7 women) underwent 20-min cycles in four randomized conditions: control (CON), sunscreen A (SSA), sunscreen B (SSB) and sunscreen C (SSC). LSR was measured by a patch on the scapular region (p < .001). CON showed higher LSR (182.21 μL/min·dm2, CI95% 168 to 195 μL/min·dm2) compared to SSA (142.10 μL/min·dm2, CI95% 128 to 155 μL/min·dm2), SSB (158.06 μL/min·dm2, CI95% 144 to 171 μL/min·dm2), and SSC (159.00 μL/min·dm2, CI95% 145 to 172 μL/min·dm2). In men, SSA showed lower LSR compared to CON, SSB, and SSC (p < .05). On the other hand, no statistically significant differences were found in LSR between SSB, SSC, and CON conditions. In women, CON was superior to all sunscreens in LSR (p < .001), and there was no difference between them (SSA, SSB, SSC, p > .05). Sunscreen reduced LSR during moderate exercise in a hot and moderate humidity environment compared to CON, especially SSA in men and all sunscreens in women.

Combination of Indomethacin with Nanostructured Lipid Carriers for Effective Anticancer Therapy

Purpose

The anticancer potential of indomethacin and other nonsteroidal anti-inflammatory drugs (NSAIDs) in vitro, in vivo, and in clinical trials is well known and widely reported in the literature, along with their side effects, which are mainly observed in the gastrointestinal tract. Here, we present a strategy for the application of the old drug indomethacin as an anticancer agent by encapsulating it in nanostructured lipid carriers (NLC). We describe the production method of IND-NLC, their physicochemical parameters, and the results of their antiproliferative activity against selected cancer cell lines, which were found to be higher compared to the activity of free indomethacin.

Methods

IND-NLC were fabricated using the hot high-pressure homogenization method. The nanocarriers were physicochemically characterized, and their biopharmaceutical behaviour and therapeutic efficacy were evaluated in vitro.

Results

Lipid nanoparticles IND-NLC exhibited a particle size of 168.1 nm, a negative surface charge (-30.1 mV), low polydispersity index (PDI of 0.139), and high encapsulation efficiency (over 99%). IND-NLC were stable for over 60 days and retained integrity during storage at 4 °C and 25 °C. The potential therapeutic benefits of IND-NLC were screened using in vitro cancer models, where nanocarriers with encapsulated drug effectively inhibited the growth of breast cancer cell line MDA-MB-468 at dosage 15.7 μM.

Conclusion

We successfully developed IND-NLC for delivery of indomethacin to cancer cells and confirmed their antitumoral efficacy in in vitro studies. The results suggest that indomethacin encapsulated in lipid nanoparticles possesses high anticancer potential. Moreover, the presented strategy is highly promising and may offer a new alternative for future therapeutic drug innovations.

Ex vivo Evaluation of a Liposome-Mediated Antioxidant Delivery System on Markers of Skin Photoaging and Skin Penetration

Purpose

The topical application of antioxidants has been shown to augment the skin's innate antioxidant system and enhance photoprotection. A challenge of topical antioxidant formulation is stability and penetrability. The use of a targeted drug delivery system may improve the bioavailability and delivery of antioxidants. In this ex vivo study, we assessed the effects of the topical application of a liposome-encapsulated antioxidant complex versus a free antioxidant complex alone on skin photoaging parameters and penetrability in human skin explants.

Patients and Methods

Human organotypic skin explant cultures (hOSEC) were irradiated to mimic photoaging. The encapsulated antioxidant complex and free antioxidant complex were applied topically onto the irradiated hOSEC daily for 7 days. The two control groups were healthy untreated hOSEC and irradiated hOSEC. Photoprotective efficacy was measured with pro-inflammatory cytokine (IL-6 and IL-8) and matrix metalloproteinase 9 (MMP-9) secretion. Cell viability and metabolic activity were measured via resazurin assay. Tissue damage was evaluated via lactate dehydrogenase (LDH) cytotoxicity assay. Skin penetration of the encapsulated antioxidant complex was assessed via fluorescent dye and confocal microscopy.

Results

Compared to healthy skin, irradiated skin experienced increases in IL-6, IL-8 (p < 0.05), and MMP-9 (p < 0.05) secretion. After treatment with the encapsulated antioxidant complex, there was a 39.3% reduction in IL-6 secretion, 49.8% reduction in IL-8 (p < 0.05), and 38.5% reduction in MMP-9 (p < 0.05). After treatment with the free antioxidant complex, there were no significant differences in IL-6, IL-8, or MMP-9 secretion. Neither treatment group experienced significant LDH leakage or reductions in metabolic activity. Liposomes passed through the stratum corneum and into the epidermis.

Conclusion

The topical application of a liposome-encapsulated antioxidant complex containing ectoin, astaxanthin-rich microalgae Haematococcus pluvialis extract, and THDA improves penetrability and restored IL-6, IL-8, and MMP-9 levels in irradiated human skin explants, which was not seen in the comparator free antioxidant complex group.

Ultrasmall Solid-Lipid Nanoparticles via the Polysorbate Sorbitan Phase-Inversion Temperature Technique: A Promising Vehicle for Antioxidant Delivery into the Skin

Solid lipid nanoparticles promote skin hydration via stratum corneum occlusion, which prevents water loss by evaporation, and via the reinforcement of the skin's lipid-film barrier, which occurs through the adhesion of the nanoparticles to the stratum corneum. The efficacy of both phenomena correlates with lower nanoparticle size and the increased skin permeation of loaded compounds. The so-called Polysorbate Sorbitan Phase-Inversion Temperature method has, therefore, been optimized in this experimental work, in order to engineer ultrasmall solid-lipid nanoparticles that were then loaded with α-tocopherol, as the anti-age ingredient for cosmetic application. Ultrasmall solid-lipid nanoparticles have been proven to be able to favor the skin absorption of loaded compounds via the aforementioned mechanisms.

Co-Encapsulation of Curcumin and α-Tocopherol in Bicosome Systems: Physicochemical Properties and Biological Activity

A novel co-encapsulation system called bicosomes (bicelles within liposomes) has been developed to overcome the limitations associated with the topical application of curcumin (cur) and α-tocopherol (α-toc). The physicochemical properties and biological activity in vitro of bicosome systems were evaluated. Bicelles were prepared with DPPC, DHPC, cur, and α-toc (cur/α-toc-bicelles). Liposomal vesicles loading cur/α-toc-bicelles were prepared with Lipoid P-100 and cholesterol-forming cur/α-toc-bicosomes. Three cur/α-toc-bicosomes were evaluated using different total lipid percentages (12, 16, and 20% w/v). The results indicated that formulations manage to solubilize cur and α-toc in homogeneous bicelles < 20 nm, while the bicosomes reaches 303-420 nm depending on the total lipid percentage in the systems. Bicosomes demonstrated high-encapsulation efficiency (EE) for cur (56-77%) and α-toc (51-65%). The loading capacity (LC) for both antioxidant compounds was 52-67%. In addition, cur/α-toc-bicosomes decreased the lipid oxidation by 52% and increased the antioxidant activity by 60% compared to unloaded bicosomes. The cell viability of these cur/α-toc-bicosomes was >85% in fibroblasts (3T3L1/CL-173™) and ≥65% in keratinocytes (Ha-CaT) and proved to be hematologically compatible. The cur/α-toc-bicelles and cur/α-toc-bicosomes inhibited the growth of C. albicans in a range between 33 and 76%. Our results propose bicosome systems as a novel carrier able to co-encapsulate, solubilize, protect, and improve the delivery performance of antioxidant molecules. The relevance of these findings is based on the synergistic antioxidant effect of its components, its biocompatibility, and its efficacy for dermal tissue treatment damaged by oxidative stress or by the presence of C. albicans. However, further studies are needed to assess the efficacy and safety of cur/α-toc bicosomes in vitro and in vivo.

Improved infectious burn wound healing by applying lyophilized particles containing probiotics and prebiotics

Lactiplantibacillus plantarum cells were encapsulated in a mixture of cationic and anionic polymers, with the final composition stabilized through freeze-drying. A D-optimal design was used to examine the effects of different polymer concentrations as well as adding prebiotics on the probiotic viability and swelling behavior of the formulations. Scanning electron micrographs revealed stacked particles capable of rapidly absorbing significant amounts of water. These images corresponded to initial swelling percentages of around 2000% for the optimal formulation. The optimized formula had a viability percentage of more than 82%, with the stability studies suggesting that the powders should be stored at refrigerated temperatures. The physical characteristics of the optimized formula were examined to ensure compatibility with its application. According to antimicrobial evaluations, the difference in pathogen inhibition between formulated and fresh probiotics was less than a logarithm. The final formula was tested in vivo and showed improved wound healing indicators. The optimized formula resulted in a higher rate of wound closure and infection clearance. Furthermore, the molecular studies for oxidative stress indicated that the formula could modify wound inflammatory responses. In histological investigations, the probiotic-loaded particles functioned exactly as efficaciously as silver sulfadiazine ointment did.

Cosmeceutical formulations of pro-vitamin E phosphate: In-vitro release testing and dermal penetration into excised human skin

Long-term exposure to solar radiation can lead to skin damage such as photoageing, and photocarcinogenesis. This can be prevented by topically applying α-tocopherol phosphate (α-TP). The major challenge is that a significant amount of α-TP needs to reach viable skin layers for effective photoprotection. This study aims to develop candidate formulations of α-TP (gel-like, solution, lotion, and gel), and investigate formulation characteristics' effect on membrane diffusion and human skin permeation. All the formulations developed in the study had an appealing appearance and no signs of separation. All formulations had low viscosity and high spreadability except the gel. The flux of α-TP through the polyethersulfone membrane was the highest for lotion (6.63 ± 0.86 mg/cm²/h), followed by control gel-like (6.14 ± 1.76 mg/cm²/h), solution (4.65 ± 0.86 mg/cm²/h), and gel (1.02 ± 0.22 mg/cm²/h). The flux of α-TP through the human skin membrane was numerically higher for lotion compared to the gel-like (328.6 vs.175.2 µg/cm²/h). The lotion delivered 3-fold and 5-fold higher α-TP in viable skin layers at 3 h and 24 h, respectively, compared to that of the gel-like. The low skin membrane penetration rate and deposition of α-TP in viable skin layers were observed for the solution and gel. Our study demonstrated that dermal penetration of α-TP was influenced by characteristics of formulation such as formulation type, pH, and viscosity. The α-TP in the lotion scavenged higher DPPH free radicals compared to that of gel-like (almost 73% vs. 46%). The IC₅₀ of α-TP in lotion was significantly lower than that of gel-like (397.2 vs. 626.0 µg/mL). The preservative challenge test specifications were fulfilled by Geogard 221 and suggested that the combination of benzyl alcohol and Dehydroacetic Acid effectively preserved 2% α-TP lotion. This result confirms the suitability of the α-TP cosmeceutical lotion formulation employed in the present work for effective photoprotection.

Neem Oil or Almond Oil Nanoemulsions for Vitamin E Delivery: From Structural Evaluation to in vivo Assessment of Antioxidant and Anti-Inflammatory Activity

Purpose

Vitamin E (VitE) may be classified in "the first line of defense" against the formation of reactive oxygen species. Its inclusion in nanoemulsions (NEs) is a promising alternative to increase its bioavailability. The aim of this study was to compare O/W NEs including VitE based on Almond or Neem oil, showing themselves antioxidant properties. The potential synergy of the antioxidant activities of oils and vitamin E, co-formulated in NEs, was explored.

Patients and Methods

NEs have been prepared by sonication and deeply characterized evaluating size, ζ-potential, morphology (TEM and SAXS analyses), oil nanodroplet feature, and stability. Antioxidant activity has been evaluated in vitro, in non-tumorigenic HaCaT keratinocytes, and in vivo through fluorescence analysis of C. elegans transgenic strain. Moreover, on healthy human volunteers, skin tolerability and anti-inflammatory activity were evaluated by measuring the reduction of the skin erythema induced by the application of a skin chemical irritant (methyl-nicotinate).

Results

Results confirm that Vitamin E can be formulated in highly stable NEs showing good antioxidant activity on keratinocyte and on C. elegans. Interestingly, only Neem oil NEs showed some anti-inflammatory activity on healthy volunteers.

Conclusion

From the obtained results, Neem over Almond oil is a more appropriate candidate for further studies on this application.

Novel Strategies against Cancer: Dexibuprofen-Loaded Nanostructured Lipid Carriers

The aim of this work was to design innovative nanostructured lipid carriers (NLCs) for the delivery of dexibuprofen (DXI) as an antiproliferative therapy against tumoral processes, and overcome its side effects. DXI-NLC samples were prepared with beeswax, Miglyol 812 and Tween 80 using high-pressure homogenization. A two-level factorial design 2⁴ was applied to optimize the formulation, and physicochemical properties such as particle size, zeta potential, polydispersity index and entrapment efficiency were measured. Optimized parameters of DXI-NLCs exhibited a mean particle size of 152.3 nm, a polydispersity index below 0.2, and high DXI entrapment efficiency (higher than 99%). Moreover, DXI-NLCs provided a prolonged drug release, slower than the free DXI. DXI-NLCs were stable for 2 months and their morphology revealed that they possess a spherical shape. In vitro cytotoxicity and anticancer potential studies were performed towards prostate (PC-3) and breast (MDA-MB-468) cancer cell lines. The highest activity of DXI-NLCs was observed towards breast cancer cells, which were effectively inhibited at 3.4 μM. Therefore, DXI-NLCs constitute a promising antiproliferative therapy that has proven to be especially effective against breast cancer.

In vitro safety evaluation of sunscreen formulation from nanostructured lipid carriers using human cells and skin model

There is a risk of toxicological reactions due to systemic absorption and photo-instability of sunscreens. The study aimed to investigate the safety profile (cytotoxicity, phototoxicity, photostability, UV filter release profile, and skin irritation properties) of sunscreen (NLC-TRF sunscreen) produced from nanostructured lipid carriers (NLCs) and tocotrienol-rich fraction (TRF). The cytotoxicity and phototoxicity of the sunscreen were evaluated on normal human dermal fibroblast (NHDF) and skin irritation properties was tested on skin model. Besides, the photoprotection in pre- and post-UV irradiation were analysed to determine the photostability. Additionally, the release profile for UV filters (diethylamino hydroxybenzoyl hexyl benzoate (DHHB) and ethylhexyl triazone (EHT)) were evaluated. The NLC-TRF sunscreen demonstrated no cytotoxicity and skin irritation to cause cell death. It showed no phototoxic effect and high photostability up to 10 Minimal Erythema Dose (MED) to ensure high SPF value above 50 and broad-spectrum of UV absorption. The NLC-TRF sunscreen implies its safety for topical application with sustainable release profile for UV filter (cumulative release of 28% for DHHB and 40% for EHT after 8 h) due to the application of NLCs. The results suggest that the NLC-TRF sunscreen is an advanced formulation with improved stability and is safe for topical delivery.

Fibrous palygorskite clays as versatile nanocarriers for skin delivery of tea tree oils in efficient acne therapy

This paper presents a facile approach to develop palygorskite (Pal), a fibrous clay mineral, as a delivery system of tea tree oil (TTO) for topical acne therapy. The obtained TTO-Pal composite showed an efficient loading of TTO (27.4%) with a selective accumulation of terpine-4-ol and 1,8-cineole (two major antimicrobial TTO constituents), sustained release of TTO at skin physiological conditions (pH5.4, 32 °C) and superior skin sebum (2.2 g/g) absorbability. In vitro toxicological assessments showed that the Pal incorporation strategy significantly reduced the acute contact toxicity of TTO. The antimicrobial results revealed a preferable bacteriostatic effect for the TTO-Pal system towards opportunistic dermal pathogens (Escherichia coli, Staphylococcus aureus and Propionibacterium acnes) over the beneficial bacterium (Staphylococcus epidermis). Moreover, TTO-Pal based formulations exhibited pronounced clinical therapeutic efficacy in treating facial acne by rapidly reducing inflamed lesions, modulating skin sebum overproduction and restoring barrier function. This is the first report of using fibrous clay as a biocompatible nanocarrier system for topical delivery of essential oils in efficient management of facial acne with both in vitro and in vivo evidences, which may open perspectives for fibrous clay-drug delivery system in topical application and expand the high added value development of this mineral resource in the advanced healthcare fields.

Development of Stable Tocopherol Succinate-Loaded Ethosomes to Enhance Transdermal Permeation: In-Vitro and In-Vivo Characterizations

BACKGROUND

Tocopherol succinate (TS) represents synthetic derivative of α-tocopherol (vitamin E), it act as anti-aging, moisturizing and antioxidant. Ultraviolet (UV) photo stability of TS is low and it cause skin irritation.

AIM

To develop tocopherol succinate loaded ethosomal gel for topical TS delivery and to evaluate its moisturizing and anti-aging effects.

METHOD

Cold method technique was used to produce ethosomal formulations (N=9) by varying ethanol and lipid concentrations (F1-F9). The most optimized formulation (F5) was selected for further study on the basis of characterization. F5 Formulation was incorporated into gel. Ex vivo permeation study was done by using Franz diffusion cell. Non-invasive in-vivo study was performed by using corneometer for evaluation of skin moisture content and skin mechanical properties by using cutometer, for 12 weeks on human subjects (N=13).

RESULTS

Particle size (PS), zeta potential (ZP) and polydispersity index (PDI), Entrapment efficiency were found to be 179.1 nm, -13.7 mV and 0.345, 99.71% respectively. TEM depicted spherical ethosomal particles. Ethosomal gel and control gel were evaluated for Conductivity and pH. Rheological analysis revealed a non-Newtonian flow. The release profile showed Initial burst and then sustained release, release data followed Korsmeyer-Peppas model. TS loaded ethosomal gel appeared physically stable and showed significant results in terms of skin capacitance and mechanical properties.

CONCLUSION

The prepared ethosomal gel formulation containing TS is more stable with enhanced antioxidant, moisturizing properties and increased TS deposition into the skin layer.

Nanocarriers as Active Ingredients Enhancers in the Cosmetic Industry-The European and North America Regulation Challenges

“Flawless skin is the most universally desired human feature” is an iconic statement by Desmond Morris. Skin indicates one´s health and is so important that it affects a person’s emotional and psychological behavior, these facts having propelled the development of the cosmetics industry. It is estimated that in 2023, this industry will achieve more than 800 billion dollars. This boost is due to the development of new cosmetic formulations based on nanotechnology. Nanocarriers have been able to solve problems related to active ingredients regarding their solubility, poor stability, and release. Even though nanocarriers have evident benefits, they also present some problems related to the high cost, low shelf life, and toxicity. Regulation and legislation are two controversial topics regarding the use of nanotechnology in the field of cosmetics. In this area, the U.S. FDA has taken the lead and recommended several biosafety studies and post-market safety evaluations. The lack of a global definition that identifies nanomaterials as a cosmetic ingredient is a hindrance to the development of global legislation. In the EU, the legislation regarding the biosafety of nanomaterials in cosmetics is stricter. “The cost is not the only important issue, safety and the application of alternative testing methods for toxicity are of crucial importance as well”.

In Silico Evaluation of Enzymatic Tunnels in the Biotransformation of α-Tocopherol Esters

Motivation: α-Tocopherol is a molecule obtained primarily from plant sources that are important for the pharmaceutical and cosmetics industry. However, this component has some limitations such as sensitivity to oxygen, presence of light, and high temperatures. For this molecule to become more widely used, it is important to carry out a structural modification so that there is better stability and thus it can carry out its activities. To carry out this structural modification, some modifications are carried out, including the application of biotransformation using enzymes as biocatalysts. Thus, the application of a computational tool that helps in understanding the transport mechanisms of molecules in the tunnels present in the enzymatic structures is of fundamental importance because it promotes a computational screening facilitating bench applications.

Objective: The aim of this work was to perform a computational analysis of the biotransformation of α-tocopherol into tocopherol esters, observing the tunnels present in the enzymatic structures as well as the energies which correspond to the transport of molecules.

Method: To carry out this work, 9 lipases from different organisms were selected; their structures were analyzed by identifying the tunnels (quantity, conformation, and possibility of transport) and later the calculations of substrate transport for the biotransformation reaction in the identified tunnels were carried out. Additionally, the transport of the product obtained in the reaction through the tunnels was also carried out.

Results: In this work, the quantity of existing tunnels in the morphological conformational characteristics in the lipases was verified. Thus, the enzymes with fewer tunnels were RML (3 tunnels), LBC and RNL (4 tunnels), PBLL (5 tunnels), CALB (6 tunnels), HLG (7 tunnels), and LCR and LTL (8 tunnels) and followed by the enzyme LPP with the largest number of tunnels (39 tunnels). However, the enzyme that was most likely to transport substrates in terms of α-tocopherol biotransformation (in relation to the E_max and E_a energies of ligands and products) was CALB, as it obtains conformational and transport characteristics of molecules with a particularity. The most conditions of transport analysis were α-tocopherol tunnel 3 (E_max: −4.6 kcal/mol; E_a: 1.1 kcal/mol), vinyl acetate tunnel 1 (E_max: −2.4 kcal/mol; E_a: 0.1 kcal/mol), and tocopherol acetate tunnel 2 (E_max: −3.7 kcal/mol; E_a: 2 kcal/mol).

The photoprotective properties of α-tocopherol phosphate against long-wave UVA1 (385 nm) radiation in keratinocytes in vitro

UVA1 radiation (340–400 nm), especially longwave UVA1 (> 370 nm), is often ignored when assessing sun protection due to its low sunburning potential, but it generates reactive oxygen species (ROS) and is poorly attenuated by sunscreens. This study aimed to investigate if α-tocopherol phosphate, (α-TP) a promising new antioxidant, could protect against long-wave UVA1 induced cell death and scavenge UVA1 induced ROS in a skin cell model. HaCaT keratinocyte cell viability (24 h) was assessed with Alamar Blue and Neutral Red assays. The metabolism of α-TP into α-T, assessed using mass spectrometry, and the compound's radical scavenging efficacy, assessed by the dichlorodihydrofluorescein (H2DCFDA) ROS detection assay, was monitored in HaCaTs. The mechanism of α-TP ROS scavenging was determined using non-cell based DPPH and ORAC assays. In HaCaT keratinocytes, irradiated with 226 J/cm² UVA1 in low-serum (2%, starved) cell culture medium, pretreatment with 80 µM α-TP significantly enhanced cell survival (88%, Alamar Blue) compared to control, whereas α-T pre-treatment had no effect survival (70%, Alamar Blue). Pre-treatment of cells with 100 μM α-TP or 100 μM α-T before 57 J/cm² UVA1 also significantly reduced ROS generation over 2 h (24.1% and 23.9% respectively) compared to the control and resulted in α-TP bioconversion into α-T. As α-TP displayed weak antioxidant activity in the cell-free assays thus its photoprotection was assigned to its bioconversion to α-T by cellular phosphatases. Through this mechanism α-TP prevented long-wave UVA1 induced cell death and scavenged UVA1 induced ROS in skin cells when added to the starved cell culture medium before UVA1 exposure by bioconversion into α-T.

Current Advances of Nanocarrier Technology-Based Active Cosmetic Ingredients for Beauty Applications

Nanocarrier technology has been effectively applied to the development of drug delivery systems to overcome the limitations of traditional preparation. Its application has been extended to various pharmaceutical fields from injection preparation to oral preparation and external preparation, and now it has appeared in the field of cosmetics for beauty applications. The widespread influence of nanocarrier in the cosmetics industry is due to the fact that nanocarrier can effectively promote the percutaneous penetration and significantly increase skin retention of active components in functional cosmetics. Meanwhile, nanocarrier can effectively improve the water dispersion of insoluble active cosmetic ingredients, enhance the stability of efficacy components and achieve the codelivery of diverse cosmetics active ingredients. In this review, we summarized the current progress of nanocarrier technology in the functional cosmetics, including the types and the routes of dermal/transdermal drug delivery nanocarriers used in the functional cosmetics, the mechanism of nanocarriers promoting the percutaneous penetration of active cosmetic ingredients, the application and efficacy evaluation of different active cosmetic ingredients in nanocarriers and discussing the potential risks to human. This will provide a useful reference for the further development of nanocarriers in the field of functional cosmetics.

An Overview on Topical Administration of Carotenoids and Coenzyme Q10 Loaded in Lipid Nanoparticles

Carotenoids and coenzyme Q10 are naturally occurring antioxidant compounds that are also found in human skin. These bioactive compounds have been the focus of considerable research due to their antioxidant, anti-inflammatory, and photoprotective properties. In this review, the current state of the art in the encapsulation of carotenoids and coenzyme Q10 in lipid nanoparticles to improve their bioavailability, chemical stability, and skin absorption is discussed. Additionally, the main findings are highlighted on the cytotoxic and photoprotective effects of these systems in the skin.

Nanostructured lipid carriers containing chitosan or sodium alginate for co-encapsulation of antioxidants and an antimicrobial agent for potential application in wound healing

The high incidence and costs of chronic wounds in the elderly have motivated the search for innovations to improve product performance and the healing process while reducing costs. In this study, bioadhesive nanostructured lipid carriers (NLC) were developed for the co-encapsulation of compounds with antioxidant (α-tocopherol and quercetin) and antimicrobial (tea tree oil) activity for management of wounds. The NLC was produced with shea butter and argan oil, and modified with sodium alginate or chitosan to confer bioadhesive properties. Spherical nanoparticles of ~307-330 nm and zeta potential varying from -21.2 to +11.8 mV were obtained. Thermal analysis demonstrated that the lipid matrix reduced tea tree oil thermal loss (~1.8-fold). Regardless of the type of polysaccharide employed, the NLCs promoted cutaneous localization of antioxidants in damaged (subjected to incision) skin, with a ~74 to 180-fold higher delivery into the skin compared to percutaneous delivery. This result is consistent with the similar bioadhesive properties of chitosan or sodium alginate-modified NLC. Nanoencapsulation of tea tree oil did not preclude its antimicrobial effects against susceptible and resistant strains of S. aureus and P. aeruginosa, while co-encapsulation of antioxidants increased the NLC-induced fibroblasts migration, supporting their potential usefulness for management of wounds.

Development of novel polyglycerol fatty acid ester-based nanoparticles for the dermal delivery of tocopherol acetate

The aim of this study was to develop and evaluate novel polyglycerol fatty acid ester (PGFE)-based nanoparticles (NPs) for the dermal delivery of tocopherol acetate (TA). TA-loaded PGFE-based NPs (PGFE-NPs) were prepared by mixing PGFE, soya phosphatidylcholine, dimyristoylphosphatidylglycerol, and TA with film using the film rehydration and extrusion method. The prepared formulations were analyzed by dynamic light scattering, small-angle X-ray diffraction and polarization microscopy. An in vitro skin accumulation test was performed with TA under occlusive and non-occlusive applications, using Yucatan micropig skin. The size range of the TA-loaded liposome and PGFE-NPs was 107-128 nm, and they were encapsulated in 1.6-2.3 mg/mL TA. All PGFE-NP formulations were negatively charged and stable for 2 weeks. Under occlusive applications, all formulations induced small amounts of TA accumulation in the epidermis but not in the dermis. However, under non-occlusive applications, some of PGFE-NP formulations enhanced TA accumulation in the epidermis. Furthermore, only the polyglycerol 4-laurate (PG4L)-based formulation induced dermal TA accumulation with the change in the formulation from a vesicular to bilayer stacked structure following water evaporation under non-occlusive applications. These results indicated that the novel TA-loaded PG4L formulation enabled the dermal delivery of TA in non-occlusive applications.

Pharmacology and Pharmacokinetics of Vitamin E: Nanoformulations to Enhance Bioavailability

Vitamin E belongs to the family of lipid-soluble vitamins and can be divided into two groups, tocopherols and tocotrienols, with four isomers (alpha, beta, gamma and delta). Although vitamin E is widely known as a potent antioxidant, studies have also revealed that vitamin E possesses anti-inflammatory properties. These crucial properties of vitamin E are beneficial in various aspects of health, especially in neuroprotection and cardiovascular, skin and bone health. However, the poor bioavailability of vitamin E, especially tocotrienols, remains a great limitation for clinical applications. Recently, nanoformulations that include nanovesicles, solid-lipid nanoparticles, nanostructured lipid carriers, nanoemulsions, and polymeric nanoparticles have shown promising outcomes in improving the efficacy and bioavailability of vitamin E. This review focuses on the pharmacological properties and pharmacokinetics of vitamin E and current advances in vitamin E nanoformulations for future clinical applications. The limitations and future recommendations are also discussed in this review.

Bemotrizinol-Loaded Carnauba Wax-Based Nanostructured Lipid Carriers for Sunscreen: Optimization, Characterization, and In vitro Evaluation

Nanostructured lipid carriers (NLC) are aqueous dispersions of nanoparticles formed by solid and liquid lipids. In this study, NLC containing an organic UV filter, bemotrizinol, were developed for sunscreen formulation using carnauba wax and caprylic/capric triglycerides through ultrasonication technique. A Box-Behnken design was used to evaluate the influence of three variables on the particle size with the purpose of choosing the best system for further characterization. The particle size decreased as the surfactant concentration increased, reaching an average size of 122.4 ± 0.3 nm at 30 days of storage. Scanning electron microscopy showed intact and spherical particles. Thermal analysis and Fourier-transform infrared spectroscopy suggest that bemotrizinol was incorporated into the NLC. The X-ray diffraction showed a reduction in the crystallinity of the NLC. In vitro analysis indicated an improvement in the photoprotective activity of bemotrizinol when incorporated into NLC. These findings suggest a promising, stable, and biocompatible system.

The Role of Oxidative Stress in Parkinson's Disease

Parkinson’s disease (PD) is caused by progressive neurodegeneration of dopaminergic (DAergic) neurons with abnormal accumulation of α-synuclein in substantia nigra (SN). Studies have suggested the potential involvement of dopamine, iron, calcium, mitochondria and neuroinflammation in contributing to overwhelmed oxidative stress and neurodegeneration in PD. Function studies on PD-causative mutations of SNCA, PRKN, PINK1, DJ-1, LRRK2, FBXO7 and ATP13A2 further indicate the role of oxidative stress in the pathogenesis of PD. Therefore, it is reasonable that molecules involved in oxidative stress, such as DJ-1, coenzyme Q10, uric acid, 8-hydroxy-2’-deoxyguanosin, homocysteine, retinoic acid/carotenes, vitamin E, glutathione peroxidase, superoxide dismutase, xanthine oxidase and products of lipid peroxidation, could be candidate biomarkers for PD. Applications of antioxidants to modulate oxidative stress could be a strategy in treating PD. Although a number of antioxidants, such as creatine, vitamin E, coenzyme Q10, pioglitazone, melatonin and desferrioxamine, have been tested in clinical trials, none of them have demonstrated conclusive evidence to ameliorate the neurodegeneration in PD patients. Difficulties in clinical studies may be caused by the long-standing progression of neurodegeneration, lack of biomarkers for premotor stage of PD and inadequate drug delivery across blood–brain barrier. Solutions for these challenges will be warranted for future studies with novel antioxidative treatment in PD patients.

Development of folic acid-loaded nanostructured lipid carriers for topical delivery: preparation, characterisation and ex vivo investigation

The present work is designed to achieve efficient localised skin delivery of folic acid (FA)-loaded nanostructured lipid carriers (NLCs) to infer efficient treatment of skin photoageing conditions induced via excessive exposure to ultraviolet (UV) radiation. FA NLCs were prepared by high-speed homogenisation followed by ultrasonication. The obtained NLCs revealed high encapsulation efficiencies (89.42-99.26%) with nanometric particle sizes (27.06-85.36 nm) of monodisperse distribution (PDI = 0.137-0.442), zeta potential values >|27| mV, pseudoplastic rheological behaviour, good spreadability (2.25-3.30 cm) and promoted occlusive properties throughout 48 h. Optimised NLC formulations appeared as sphere-shaped particles using transmission electron microscopy, showed improved photostability of FA and prolonged in vitro release profile best fitted to Higuchi diffusion model. Ex vivo permeation and deposition of FA, employing Wistar rat skins, depicted enhanced permeability and existence of FA in skin layers after 6 h. Based on the obtained results, FA-loaded NLC formulations demonstrate a promising modality for anti-photoageing therapy.

Encapsulating plant ingredients for dermocosmetic application: an updated review of delivery systems and characterization techniques

Today, there is a rising demand and ongoing search for novel plant-derived phytochemicals in the cosmetic market owing to the growing consumer expectations worldwide for green and natural health products. Various plant ingredients, including polyphenols, oils, volatile oils, vitamins and other herbal extracts, have been extensively used in herbal cosmetics. Recent advances in encapsulation technologies have greatly improved their chemical stability, biocompatibility, skin permeability and dermocosmetic efficiency when applied topically. This comprehensive review summarizes the up-to-date information on encapsulated plant ingredients tailored for dermocosmetic application with a focus on the development of novel delivery systems. An overview of the commonly used techniques for carrier characterization, performance-related properties and toxicological evaluation is also included, which might provide guidance for researchers to select or develop appropriate assay systems.

Formulation Design, Optimization and In Vivo Evaluations of an α-Tocopherol-Containing Self-Emulsified Adjuvant System using Inactivated Influenza Vaccine

α-Tocopherol has been used as an immune supplement in humans, as an emulsion adjuvant component in several veterinary vaccines as well as an immunomodulatory component of AS03, an emulsion adjuvant that was used in an H1N1 pandemic vaccine (Pandemrix). AS03 is manufactured using microfluidization and high-pressure homogenization. Such high energy and complex manufacturing processes make it difficult and expensive to produce emulsion adjuvants on a large scale, especially in developing countries. In this study we have explored simpler, comparatively inexpensive methods, to formulate emulsion adjuvants containing α-tocopherol, that have the potential to be made in any well-established scale-up facility. This might facilitate producing and stock-piling adjuvant doses and therefore aide in pandemic preparedness. We used design of experiment as a tool to explore incorporating α-tocopherol into self-emulsified systems containing squalene oil and polysorbate 80. We created novel self-emulsified adjuvant systems (SE-AS) and evaluated their potency in vivo in BALB/c mice with inactivated quadrivalent influenza vaccine (QIV) and tested the cellular and humoral immune responses against the four vaccine strains.

Evaluation of the biocompatibility and skin hydration potential of vitamin E-loaded lipid nanosystems formulations: In vitro and human in vivo studies

Lipid-based nanosystems, such as nanostructured lipid carriers (NLC) and nanoemulsions (NE) have been described as promising alternatives to conventional formulations for increase skin hydration. Besides, these systems have been used as efficient vehicles for lipophilic molecules that improve skin properties (e.g. vitamin E). In this study, we performed comparative investigations between hydrogels formulations containing vitamin E-loaded NLC (HG-NLC_VE) and vitamin E-loaded nanoemulsion (HG-NE_VE). The experiments started with particle size measurements, which showed no significant differences between nanoparticles/nanodroplets sizes after incorporation in the hydrogel net (386 nm vs. 397 nm for HG-NLC_VE and 402 nm vs. 514 nm for HG-NE_VE). Afterwards, in vitro biocompatibility studies in human keratinocytes were carried out, being observed that the lipid-based nanosystems were more cytotoxic for the cells before incorporation in the hydrogel. Finally, the formulations hydration potential and sensory attributes for skin application were evaluated by in vitro occlusion tests and in vivo human experiments. The results showed that the HG-NLC_VE exhibited the best occlusive properties, whereas the HG-NE_VE performed a faster skin hydration effect. Furthermore, the latter was selected as the most attractive for skin application, although the HG-NLC_VE was described as more suitable to obtain a long-lasting effect. This study demonstrated the in vitro and in vivo safety and hydration potential of hydrogels containing vitamin E-loaded lipid-based nanosystems. These results establish a basis to assess the cutaneous use of these systems, despite more in vivo experiments, for longer periods and in more volunteers, are required before commercialization.

Lipid nanoparticles (SLN & NLC) for delivery of vitamin E: a comprehensive review

The antioxidative and photoprotective properties of vitamin E have caused it to be included as an active agent in various pharmaceutical and cosmetic products. However, its lipophilicity, chemical instability and poor skin penetration have limited the effectiveness of these formulations. For that reason, many attempts to include it in different drug delivery systems have been made. In recent decades, lipid nanoparticles have received special attention due to their advantages of compatibility with the skin, ability to enhance penetration of drugs in the stratum corneum, protection of the encapsulated substance against degradation induced by the external medium and control of drug release. This work reviews the current status of the encapsulation of vitamin E in lipid nanoparticles. We describe the most important methods for obtaining and characterizing lipid nanoparticles containing vitamin E (LNP-VE), various techniques for the evaluation of vitamin E's properties after encapsulation, the main in vitro and in vivo studies of the potential effectiveness or toxicity of LNP-VE, the formulations and stability studies of this delivery system, the commercial products based on LNP-VE and the regulatory aspects related to lipid nanoparticles. Finally, we discuss the most relevant advantages of encapsulating vitamin E in such particles and critical aspects that still demand attention to enhance the potential of solid lipid nanoparticles to deliver vitamin E.

Optimization of nutraceutical coenzyme Q10 nanoemulsion with improved skin permeability and anti-wrinkle efficiency

Coenzyme Q10 (CoQ10) is an insoluble, poorly permeable antioxidant with great biological value which acts as anti-aging and anti-wrinkle agent. To improve its permeability through topical application, the current study aimed at formulating oil/water (o/w) nanoemulsion (NE) as an efficient vehicle for delivering (CoQ10) through the skin barriers. The solubility of (CoQ10) was tested for various oils, surfactants (S), and co-surfactants (CoS). The NE region was determined by constructing pseudoternary phase diagrams. NE formulae containing 1, 2, and 3% w/w drug have been subjected to thermodynamic stability test. The formulae that passed thermodynamic stability tests were characterized by physical properties as pH, viscosity, refractive index, droplet size, zeta-potential, TEM, electroconductivity, in vitro release, and ex vivo permeation. The formula 'F2' containing 10% w/w isopropyl myristate (oil phase), 60% w/w of Tween 80: Transcutol HP mixture (S/CoS_mix) at ratio 2:1, 30% w/w water and 2% w/w drug was evaluated for its anti-wrinkle efficiency using an animal model. The 'F2' formula showed 11.76 ± 1.1 nm droplet size, 1.4260 ± 0.0016 refractive index, 0.228 PDI, -14.7 ± 1.23 mv zeta potential, 7.06 ± 0.051 pH, 199.05 ± 0.35 cp viscosity, and the highest percentage of drug release in the selected dissolution media. About 47.21% of the drug was released in phosphate buffer 7.4 containing 5% w/v Labrasol and 5% w/v isopropyl alcohol through 24 h. It also showed the highest drug flux (J_ss = 3.164 µg/cm²/h), enhancement ratio (E_r = 8.32), and permeability coefficient (K_p = 22.14 × 10^-4 cm²/h). CoQ10 NE reduced the skin wrinkles and gave the skin smooth appearance. Our investigation suggests the potential use of NE as a vehicle for enhancing solubility and permeability of CoQ10 and thus improving its anti-wrinkle efficiency.

Can regenerative medicine and nanotechnology combine to heal wounds? The search for the ideal wound dressing

Skin is the outermost covering of the human body and at the same time the largest organ comprising 15% of body weight and 2 m2 surface area. Skin plays a key role as a barrier against the outer environment depending on its thickness, color and structure, which differ from one site to another. The four major types of problematic wounds include ulcers (diabetic, venous, pressure) and burn wounds. Developing novel dressings helps us to improve the wound healing process in difficult patients. Recent advances in regenerative medicine and nanotechnology are revolutionizing the field of wound healing. Antimicrobial activity, exogenous cell therapy, growth factor delivery, biodegradable and biocompatible matrix construction, all play a role in hi-tech dressing design. In the present review, we discuss how the principles of regenerative medicine and nanotechnology can be combined in innovative wound dressings.

Protein-based nanoformulations for α-tocopherol encapsulation

Nanoparticles of BSA and silk fibroin (SF) with entrapped α-tocopherol were produced via ultrasonic emulsification. Populations with particle size of 200-300 nm and highly negatively charged were obtained for all the tested formulations. Entrapment efficiencies of around 99% revealed the effective encapsulation of α-tocopherol into the produced nanoformulations. Generally, these nanodevices did not induce significant cytotoxicity to human skin keratinocytes for all the concentrations tested. The developed formulations showed free radical scavenging of ABTS.⁺ ability resulting from the synergistic effect between the proteins in formulation and the entrapped tocopherol. Overall, the results contribute for the establishment of BSA:VO and BSA:SF:VO as biodegradable and non-toxic nanoformulations for the functionalization of textile devices and controlled delivery of tocopherol into the skin.

Preclinical safety of solid lipid nanoparticles and nanostructured lipid carriers: Current evidence from in vitro and in vivo evaluation

Solid lipid nanoparticles (SLN) and nanostructured lipid carriers (NLC) were designed as exceptionally safe colloidal carriers for the delivery of poorly soluble drugs. SLN/NLC have the particularity of being composed of excipientsalready approved for use in medicines for human use, which offers a great advantage over any other nanoparticulate system developed from novel materials. Despite this fact, any use of excipients in new route of administration or in new dosage form requires evidence of safety. After 25 years of research on SLN and NLC, enough evidence on their preclinical safety has been published. In the present work, published data on in vitro and in vivo compatibility of SLN/NLC have been surveyed, in order to provide evidence of high biocompatibility distinguished by intended administration route. We also identified critical factors and possible weak points in SLN/NLC formulations, such as the effect of surfactants on the cell viability in vitro, which should be considered for further development.

Current application of phytocompound-based nanocosmeceuticals for beauty and skin therapy

Phytocompounds have been used in cosmeceuticals for decades and have shown potential for beauty applications, including sunscreen, moisturizing and antiaging, and skin-based therapy. The major concerns in the usage of phyto-based cosmeceuticals are lower penetration and high compound instability of various cosmetic products for sustained and enhanced compound delivery to the beauty-based skin therapy. To overcome these disadvantages, nanosized delivery technologies are currently in use for sustained and enhanced delivery of phyto-derived bioactive compounds in cosmeceutical sectors and products. Nanosizing of phytocompounds enhances the aseptic feel in various cosmeceutical products with sustained delivery and enhanced skin protecting activities. Solid lipid nanoparticles, transfersomes, ethosomes, nanostructured lipid carriers, fullerenes, and carbon nanotubes are some of the emerging nanotechnologies currently in use for their enhanced delivery of phytocompounds in skin care. Aloe vera, curcumin, resveratrol, quercetin, vitamins C and E, genistein, and green tea catechins were successfully nanosized using various delivery technologies and incorporated in various gels, lotions, and creams for skin, lip, and hair care for their sustained effects. However, certain delivery agents such as carbon nanotubes need to be studied for their roles in toxicity. This review broadly focuses on the usage of phytocompounds in various cosmeceutical products, nanodelivery technologies used in the delivery of phytocompounds to various cosmeceuticals, and various nanosized phytocompounds used in the development of novel nanocosmeceuticals to enhance skin-based therapy.

The Use of Liprotides To Stabilize and Transport Hydrophobic Molecules

Recently, it has been shown that different complexes consisting of protein and fatty acids, which we call liprotides, have common functional and structural features. Liprotides can transfer their fatty acid content to membranes, highlighting the potential to incorporate other small molecules and help transfer them to membranes. In this study, this potential was explored with regard to the poorly water-soluble vitamin E compound α-tocopherol (Toc). Uptake into liprotides increased Toc solubility and chemical stability. The liprotide-Toc complexes retained the characteristic liprotide structure with a core of fatty acid surrounded by protein. Toc and fatty acid could be transferred to artificial vesicles upon being incorporated into the liprotide complex. Extending this work, we found that free tryptophan and the vitamin A precursor retinaldehyde could also be incorporated in the liprotides; however, other small molecules failed to be taken up, and we conclude that successful incorporation requires a hydrophobic terminal moiety that can be accommodated within the micelle interior of the liprotides. Nevertheless, our work suggests that liprotides are able to stabilize and transport a number of otherwise insoluble small molecules with significant potential health benefits.