Strat-M® positioning for skin permeation studies: A comparative study including EpiSkin® RHE, and human skin

In the development and optimization of dermatological products, In Vitro Permeation Testing (IVPT) is pivotal for controlled study of skin penetration. To enhance standardization and replicate human skin properties reconstructed human skin and synthetic membranes are explored as alternatives. Strat-M® is a membrane designed to mimic the multi-layered structure of human skin for IVPT. For instance, in Strat-M®, the steady-state fluxes (JSS) of resorcinol in formulations free of permeation enhancers were found to be 41 ± 5 µg/cm2·h for the aqueous solution, 42 ± 6 µg/cm2·h for the hydrogel, and 40 ± 6 µg/cm2·h for the oil-in-water emulsion. These results were closer to excised human skin (5 ± 3, 9 ± 2, 13 ± 6 µg/cm2·h) and surpassed the performance of EpiSkin® RHE (138 ± 5, 142 ± 6, and 162 ± 11 µg/cm2·h). While mass spectrometry and Raman microscopy demonstrated the qualitative molecular similarity of EpiSkin® RHE to human skin, it was the porous and hydrophobic polymer nature of Strat-M® that more faithfully reproduced the skin's diffusion-limiting barrier. Further validation through similarity factor analysis (∼80-85%) underscored Strat-M®'s significance as a reliable substitute for human skin, offering a promising approach to enhance realism and reproducibility in dermatological product development.

Evaluation of Two Novel Hydantoin Derivatives Using Reconstructed Human Skin Model EpiskinTM: Perspectives for Application as Potential Sunscreen Agents

This study aimed to assess two novel 5-arylideneimidazolidine-2,4-dione (hydantoin) derivatives (JH3 and JH10) demonstrating photoprotective activity using the reconstructed human skin model Episkin^TM. The skin permeability, irritation, and phototoxicity of the compounds was evaluated in vitro. Moreover, the in vitro genotoxicity and human metabolism of both compounds was studied. For skin permeation and irritation experiments, the test compounds were incorporated into a formulation. It was shown that JH3 and JH10 display no skin irritation and no phototoxicity. Both compounds did not markedly enhance the frequency of micronuclei in CHO-K1 cells in the micronucleus assay. Preliminary in vitro studies with liver microsomes demonstrated that hydrolysis appears to constitute their important metabolic pathway. Episkin^TM permeability experiments showed that JH3 permeability was lower than or close to currently used UV filters, whereas JH10 had the potential to permeate the skin. Therefore, a restriction of this compound permeability should be obtained by choosing the right vehicle or by optimizing it, which should be addressed in future studies.

The fabrication and assessment of mosquito repellent cream for outdoor protection

Mosquito-borne infections like dengue, malaria, chikungunya, etc. are a nuisance and can cause profound discomfort to people. Due to the objectional side effects and toxicity associated with synthetic pyrethroids, N,N-diethyl-3-methylbenzamide (DEET), N,N-diethyl phenylacetamide (DEPA), and N,N-di ethyl benzamide (DEBA) based mosquito repellent products, we developed an essential oil (EO) based mosquito repellent cream (EO-MRC) using clove, citronella and lemongrass oil. Subsequently, a formulation characterization, bio-efficacy, and safety study of EO-MRC were carried out. Expression of Anti-OBP2A and TRPV1 proteins on mosquito head parts were studied by western blotting. In-silico screening was also conducted for the specific proteins. An FT-IR study confirmed the chemical compatibility of the EOs and excipients used in EO-MRC. The thermal behaviour of the best EOs and their mixture was characterized by thermogravimetric analysis (TGA). GC-MS examination revealed various chemical components present in EOs. Efficacy of EO-MRC was correlated with 12% N,N-diethyl benzamide (DEBA) based marketed cream (DBMC). Complete protection time (CPT) of EO-MRC was determined as 228 min. Cytotoxicity study on L-132 cell line confirmed the non-toxic nature of EO-MRC upon inhalation. Acute dermal irritation study, acute dermal dose toxicity study, and acute eye irritation study revealed the non-toxic nature of EO-MRC. Non-target toxicity study on Danio rerio confirmed EO-MRC as safer for aquatic non-target animals. A decrease in the concentration of acetylcholinesterase (AChE) was observed in transfluthrin (TNSF) exposed Wistar rats. While EO-MRC did not alter the AChE concentrations in the exposed animals. Results from western blotting confirmed that Anti-OBP2A and TRPV1 proteins were inhibited in TNSF exposed mosquitoes. Mosquitoes exposed to EO-MRC showed a similar expression pattern for Anti-OBP2A and TRPV1 as the control group. In silico study revealed eight identified compounds of the EOs play significant roles in the overall repellency property of the developed product. The study emphasizes the mosquito repellent activity of EO-MRC, which could be an effective, eco-friendly, and safer alternative to the existing synthetic repellents for personal protection against mosquitoes during field conditions.

Nanoparticle impregnated self-supporting protein gel for enhanced reduction in oxidative stress: A molecular dynamics insight for lactoferrin-polyphenol interaction

In the present work, lactoferrin (Lf) based nanoparticle incorporated self-supporting gel encapsulating a flavonoid, quercetin (Q), was developed. The complex formation between Lf and Q was assessed using molecular docking and dynamics simulation that lactoferrin and quercetin showed strong interaction and binding supporting hydrophobic interaction. The microscopic, spectroscopic, and x-ray techniques were used to characterize the gel extensively. In vitro drug release was studied to understand the release pattern of quercetin from the protein gel. The viscosity of the gel and its rheological characteristics were determined using a Brookfield viscometer. Ex vivo skin permeation studies using vertical diffusion cells were carried out to understand its skin permeation properties. The gel showed strong anti-oxidant activity using the DPPH scavenging assay. The enhanced effect of the Lf-Q complex on antioxidant enzyme activity (superoxide dismutase, catalase, and malondialdehyde), was supported by molecular dynamics, surface hydrophobicity, and in vitro studies. To investigate the effect of the gel on angiogenesis, the chorioallantoic membrane assay was performed and its compatibility with erythrocytes was also assessed. Suitability for topical administration was assessed using skin irritation studies performed on Sprague Dawley rats. The overall results suggest that the developed NiPG is suitable for cutaneous localization of quercetin with enhanced antioxidant activity.

Glimepiride-Loaded Nanoemulgel; Development, In Vitro Characterization, Ex Vivo Permeation and In Vivo Antidiabetic Evaluation

Glimepiride (GMP), an oral hypoglycemic agent is extensively employed in the treatment of type 2 diabetes. Transdermal delivery of GMP has been widely investigated as a promising alternative to an oral approach but the delivery of GMP is hindered owing to its low solubility and permeation. The present study was designed to formulate topical nanoemulgel GMP system and previously reported solubility enhanced glimepiride (GMP/βCD/GEL-44/16) in combination with anti-diabetic oil to enhance the hypoglycemic effect. Nanoemulsions were developed using clove oil, Tween-80, and PEG-400 and were gelled using xanthan gum (3%, w/w) to achieve the final nanoemulgel formulations. All of the formulations were evaluated in terms of particle size, zeta potential, pH, conductivity, viscosity, and in vitro skin permeation studies. In vivo hypoglycemic activity of the optimized nanoemulgel formulations was evaluated using a streptozocin-induced diabetes model. It was found that a synergistic combination of GMP with clove oil improved the overall drug permeation across the skin membrane and the hypoglycemic activity of GMP. The results showed that GMP/βCD/GEL-44/16-loaded nanoemulgel enhanced the in vitro skin permeation and improved the hypoglycemic activity in comparison with pure and marketed GMP. It is suggested that topical nano emulsion-based GMP gel and GMP/βCD/GEL-44/16 could be an effective alternative for oral therapy in the treatment of diabetes.

Tandem mass spectrometry of aqueous extract from Ficus dubia sap and its cell-based assessments for use as a skin antioxidant

Since 2006, Ficus dubia has been reported as a new Ficus species in Thailand. As per our recent report, the red-brown aqueous extract of F. dubia sap (FDS) has been determined to strongly exhibit in vitro anti-radicals. However, the phytochemicals in the FDS extract related to health-promoting antioxidation have not been explored. Thus, in this study, we aimed to investigate the chemical components of the F. dubia sap extract by liquid chromatography-electrospray ionization quadrupole time-of-flight mass spectrometry (LC-ESI-MS/QTOF-MS) and its potential use in cosmetics in terms of cellular antioxidation on keratinocytes (HaCaT), phototoxicity, and irritation on 3D skin cell models following standard tests suggested by the Organization for Economic Cooperation and Development (OECD). It was found that the sap extract was composed of quinic acid and caffeoyl derivatives (e.g., syringoylquinic acid, 3-O-caffeoylquinic acid, 4-O-caffeoylquinic acid, and dimeric forms of caffeoylquinic acids). The extract has significantly exhibited antioxidant activity against H2O2-induced oxidative stress in HaCaT cells. The cellular antioxidative effect of the FDS extract was remarkably dependent on the presence of 3- and 4-O-caffeoylquinic acid in the extract. Furthermore, the FDS extract showed negative results on skin phototoxicity and irritation. Overall, the results reveal that the FDS extract could be developed as a new antioxidant candidate for a skin healthcare product.

Tailoring of Retinyl Palmitate-Based Ethosomal Hydrogel as a Novel Nanoplatform for Acne Vulgaris Management: Fabrication, Optimization, and Clinical Evaluation Employing a Split-Face Comparative Study

AIM

Retinyl palmitate (RP), the most stable vitamin A derivative, is used to treat photoaging and other skin disorders. The need to minimize the adverse effects of topical drug administration has led to an enhanced interest in loading RP on ethosomes for topical drug delivery. The aim of the current study was to prepare and compare the performance of RP decorated ethosomal hydrogel with tretinoin cream in the treatment of acne vulgaris as an approach to improve drug efficacy and decrease its side effects.

METHODS

RP-loaded ethosomes were prepared using the injection sonication technique. A Box-Behnken design using Design Expert® software was used for the optimization of formulation variables. Particle size, zeta potential (ZP), entrapment efficiency percent (EE%), % drug release, and permeation over 24 h of different formulations were determined. The optimal formulation was incorporated into a hydrogel. Finally, the efficacy and tolerability of the optimized RP ethosomal hydrogel were clinically evaluated for acne treatment using a split-face comparative clinical study.

RESULTS

The optimized ethosomal RP showed particle size of 195.8±5.45 nm, ZP of -62.1±2.85 mV, EE% of 92.63±4.33%, drug release % of 96.63±6.81%, and drug permeation % of 85.98 ±4.79%. Both the optimized RP ethosomal hydrogel and tretinoin effectively reduced all types of acne lesions (inflammatory, non-inflammatory, and total lesions). However, RP resulted in significantly lower non-inflammatory and total acne lesion count than the marketed tretinoin formulation. Besides, RP-loaded ethosomes showed significantly improved tolerability compared to marketed tretinoin with no or minimal skin irritation symptoms.

CONCLUSION

RP ethosomal hydrogel is considerably effective in controlling acne vulgaris with excellent skin tolerability. Therefore, it represents an interesting alternative to conventional marketed tretinoin formulation for topical acne treatment.

Prognostic tools for hypertrophic scar formation based on fundamental differences in systemic immunity

Unpredictable hypertrophic scarring (HS) occurs after approximately 35% of all surgical procedures and causes significant physical and psychological complaints. Parallel to the need to understanding the mechanisms underlying HS formation, a prognostic tool is needed. The objective was to determine whether (systemic) immunological differences exist between patients who develop HS and those who develop normotrophic scars (NS) and to assess whether those differences can be used to identify patients prone to developing HS. A prospective cohort study with NS and HS groups in which (a) cytokine release by peripheral blood mononuclear cells (PBMC) and (b) the irritation threshold (IT) after an irritant (sodium lauryl sulphate) patch test was evaluated. Univariate regression analysis of PBMC cytokine secretion showed that low MCP-1, IL-8, IL-18 and IL-23 levels have a strong correlation with HS (P < .010-0.004; AUC = 0.790-0.883). Notably, combinations of two or three cytokines (TNF-a, MCP-1 and IL-23; AUC: 0.942, Nagelkerke R2 : 0.727) showed an improved AUC indicating a better correlation with HS than single cytokine analysis. These combination models produce good prognostic results over a broad probability range (sensitivity: 93.8%, specificity 86.7%, accuracy 90,25% between probability 0.3 and 0.7). Furthermore, the HS group had a lower IT than the NS group and an accuracy of 68%. In conclusion, very fundamental immunological differences exist between individuals who develop HS and those who do not, whereas the cytokine assay forms the basis of a predictive prognostic test for HS formation, the less invasive, easily performed irritant skin patch test is more accessible for daily practice.

Real world-like simulations show efficient predictive power of in vitro skin corrosion tests used as stand-alone and in combination and how can toxicologists take advantage of them

Historically, performance of in vitro toxicology test methods has been evaluated and considered for regulatory purposes based on sensitivity & specificity values derived from validation studies. Other indicators are however useful to evaluate in vitro tests such as positive & negative predictive values (PPV & NPV), likelihood ratios (LRs) or odds ratio (OR). These indicators, which are routinely used in diagnostic tests, if adapted and adequately applied to in vitro tests would help determine their realistic predictive power in real world-like situation and help risk assessors know how they can rely on in vitro tests used for their safety assessments. This paper performs a series of simulations considering the actual distribution in ECHA C&L inventory of skin corrosive chemicals to calculate several of these indicators of performance (PPV, NPV, LRs, OR). It shows applied examples of predictive power on EpiSkin™ and SkinEthic™ RHE two validated in vitro skin corrosive tests, explains how to build testing strategies based on these examples, compares so called 'bottom-up' and 'top-down' approaches, and demonstrates the number of tests required, and how risk assessors can practically take advantage of this.

Self-Assembled Lecithin/Chitosan Nanoparticles Based on Phospholipid Complex: A Feasible Strategy to Improve Entrapment Efficiency and Transdermal Delivery of Poorly Lipophilic Drug

PURPOSE

Lecithin/chitosan nanoparticles have shown great promise in the transdermal delivery of therapeutic agents. Baicalein, a natural bioactive flavonoid, possesses multiple biological activities against dermatosis. However, its topical application is limited due to its inherently poor hydrophilicity and lipophilicity. In this study, the baicalein-phospholipid complex was prepared to enhance the lipophilicity of baicalein and then lecithin/chitosan nanoparticles loaded with the baicalein-phospholipid complex were developed to improve the transdermal retention and permeability of baicalein.

METHODS

Lecithin/chitosan nanoparticles were prepared by the solvent-injection method and characterized in terms of particle size distribution, zeta potential, and morphology. The in vitro release, the ex vivo and in vivo permeation studies, and safety evaluation of lecithin/chitosan nanoparticles were performed to evaluate the effectiveness in enhancing transdermal retention and permeability of baicalein.

RESULTS

The lecithin/chitosan nanoparticles obtained by the self-assembled interaction of chitosan and lecithin not only efficiently encapsulated the drug with high entrapment efficiency (84.5%) but also provided sustained release of baicalein without initial burst release. Importantly, analysis of the permeation profile ex vivo and in vivo demonstrated that lecithin/chitosan nanoparticles prolonged the retention of baicalein in the skin and efficiently penetrated the barrier of stratum corneum without displaying skin irritation.

CONCLUSION

These results indicate the potential of drug-phospholipid complexes in enhancing the entrapment efficiency and self-assembled lecithin/chitosan nanoparticles based on phospholipid complexes in the design of a rational transdermal delivery platform to improve the efficiency of transdermal therapy by enhancing its percutaneous retention and penetration in the skin.

Novel Clove Essential Oil Nanoemulgel Tailored by Taguchi's Model and Scaffold-Based Nanofibers: Phytopharmaceuticals with Promising Potential as Cyclooxygenase-2 Inhibitors in External Inflammation

PURPOSE

Clove essential oil is a phytochemical possessing a vast array of biological activities. Nevertheless, fabricating nano topical delivery systems targeted to augment the anti-inflammatory activity of the oil has not been investigated so far. Accordingly, in this study, controlled release nanoparticulate systems, namely nanoemulgel and nanofibers (NFs), of the oil were developed to achieve such goal.

METHODS

The nanoemulsion was incorporated in the hydrogel matrix of mixed biopolymers - chitosan, guar gum and gum acacia - to formulate nanoemulsion-based nanoemulgel. Taguchi's model was adopted to evaluate the effect of independently controlled parameters, namely, the concentration of chitosan (X1), guar gum (X2), and gum acacia (X3) on different dependently measured parameters. Additionally, the nanoemulsion-based NFs were prepared by the electrospinning technique using polyvinyl alcohol (PVA) polymer. Extensive in vitro, ex vivo and in vivo evaluations of the aforementioned formulae were conducted.

RESULTS

Both Fourier transform-infrared spectroscopy (FT-IR) and differential scanning calorimetry (DSC) established the complete dispersion of the nanoemulsion in the polymeric matrices of the prepared nanoemulgel and NFs. The ex vivo skin permeation data of clove essential oil from the prepared formulations showed that NFs can sustain its penetration through the skin comparably with nanoemulgel. Topical treatment with NFs (once application) and nanoemulgel (twice application) evoked a marvelous in vivo anti-inflammatory activity against croton oil-induced mouse skin inflammation model when compared with pure clove essential oil along with relatively higher efficacy of medicated NFs than that of medicated nanoemulgel. Such prominent anti-inflammatory activity was affirmed by histopathological and immunohistochemical examinations.

CONCLUSION

These results indicated that nanoemulsion-based nanoemulgel and nanoemulsion-based NFs could be introduced to the phytomedicine field as promising topical delivery systems for effective treatment of inflammatory diseases instead of nonsteroidal anti-inflammatory drugs that possess adverse effects.

Potential application of novel liquid crystal nanoparticles of isostearyl glyceryl ether for transdermal delivery of 4-biphenyl acetic acid

Novel liquid crystal nanoparticles (LCNs) composed of isostearyl glyceryl ether (GE-IS) and ethoxylated hydrogenated castor oil (HCO-60) were developed for the enhanced transdermal delivery of 4-biphenyl acetic acid (BAA). The physical properties and pharmaceutical properties of the LCNs were measured. The interaction between the intercellular lipid model of the stratum corneum and the LCNs was observed to elucidate the skin permeation mechanism. In the formulation, the LCNs form niosomes with mean particles sizes of 180-300 nm. The skin absorption mechanisms of LCNs are different, depending upon the application and buffer concentration. The LCNs composed of GE-IS and HCO-60 are attractive tools for use as transdermal drug delivery systems carriers for medicines and cosmetics, due to their high efficiency and safety.

Skin irritation potential of graphene-based materials using a non-animal test

Besides inhalation, skin contact may be considered one of the most relevant exposure routes to graphene-based materials (GBMs). However, very few data on the cutaneous toxicity of these materials are available, so far. This study is focused on skin irritation potential of a panel of GBMs: few-layer graphene (FLG), exfoliated by ball milling of graphite, FLG exfoliated by ultrasonication using sodium dodecyl sulfate (FLG-SDS) or sodium dodecylbenzenesulfonate (FLG-SDBS), CVD-graphene, obtained by chemical vapor deposition, graphene oxide (GO) and reduced GO (rGO). Skin irritation was assessed using the SkinEthic™ Reconstructed human Epidermis (RhE), following the Organisation for Economic Co-operation and Development (OECD) Test Guideline (TG) 439. Even though not validated for nanomaterials, the OCED TG 439 turned out to be applicable also for GBM testing, since no interference with the methylthiazolyldiphenyl-tetrazolium bromide (MTT) reduction, used as a final readout, was found. Furthermore, direct epidermal exposure to powdered GBMs mimics the actual human exposure, avoiding interference by the cell culture medium (protein corona formation). Only GBMs prepared with irritant surfactants (FLG-SDS and FLG-SDBS), but not the others, reduced RhE viability at levels lower than those predicting skin irritation (≤50%), suggesting irritant properties. This result was further confirmed by measuring cytokine (IL-1α, IL-6 and IL-8) release by GBM-treated RhE and by histological analysis as additional readouts to implement the guideline. On the whole, these results demonstrate that GBMs prepared with non-irritant exfoliation agents do not induce skin irritation after a single acute exposure.

Formulation, characterization and in vivo evaluation of Hedera helix L., topical dosage forms

The purpose of this study was to prepare topical formulations of micro emulsion, gel and ointment containing the Hedera helix L. extracts against asthma and to evaluate the physicochemical characteristics. A validated HPLC method was used for the analysis of blood plasma. In-vivo studies of the drugs were compared in rabbit plasma with oral dosing. Stability studies were performed for 3 months. The results showed that formulations were stable. No Skin irritation observed on rabbits. The optimized micro emulsion and gel showed fast absorption. Maximal plasma concentration (c_max) and the maximal time to reach cmax (tmax) were 70.226μg/mL, 75.26μg/mL and 2 hours for the micro emulsion and gel, 90.11μg/mL and 1 hour for the oral drug syrup respectively. Pharmacokinetic parameters such as t_max, c_max and AUC of the selected formulations and oral dosing were significantly different (P < 0.01).

Stereochemical Strategy Advances Microbially Antiadhesive Cotton Textile in Safeguarding Skin Flora

Microbial contamination on cotton textiles (CT) negatively affects people's health as well as the textile itself during use and storage. Using antimicrobial CT in a body-safe manner is currently still a challenge because it is difficult to balance killing microbes and protecting skin flora. Herein, a borneol-decorated CT (BDCT) through coupling of borneol 4-formylbenzoate molecules onto the amino-modified CT is reported. This BDCT shows strong and broad-spectrum microbially antiadhesive activities against gram-positive bacteria (Staphylococcus aureus and S. epidermidis), gram-negative bacteria (Escherichia coli and Pseudomonas aeruginosa), and fungi (Aspergillus niger, Mucor racemosus, and Candida albicans). Because of its unique stereochemical microbial antiadhesion mechanism, BDCT is harmless to skin flora. In addition, BDCT exhibits prominent durability of microbially antiadhesive capability by bearing 50 times of accelerated laundering. Therefore, this stereochemical BDCT strategy shows great potential for applications in the new generation of textiles, food packaging, and medical protection.

Study of the potential adverse effects caused by the dermal application of Dillenia indica L. fruit extract standardized to betulinic acid in rodents

This study aimed to evaluate the potential adverse effects of the dermal administration of Dillenia indica Linnaeus (D. indica) fruit extract in healthy rodents; the extract was standardized to betulinic acid. In the initial phase, the acute effects were evaluated on the skin application site of a single extract dose. A skin irritation test was performed in male Wistar rats (n = 8/group) receiving the extract (50–150 mg/mL) with betulinic acid (0.5–1.5%, respectively). A photosensitivity test was performed in male BALB/c mice (n = 6/group) receiving the extract (150 mg/mL). Afterwards, other BALB/c mice (n = 20, male:female, 1:1) were used to assess the systemic alterations caused by 14 daily repeated doses (150 mg/mL) by monitoring the effects on mortality, body morphology, behavior, nutrition status, neuromotor reactions, organ morphology and weight, and blood tests. At this time, 0.5 mg/mL clobetasol was used as the positive control. The skin irritation index suggested that negligible skin irritation had occurred, even when the extract was applied to the rat skin at 150 mg/mL. However, the extract acted as a photosensitizer on mouse skin, showing a photosensitizing activity close to that of 10 mg/mL 5-methoxypsoralen. Repeated doses caused no mouse mortality, aggressiveness, piloerection, diarrhea, convulsions, neuromotor alterations or nutrition status changes. The mouse organ weights did not change, and the mice did not have alterations in their blood compositions. Clobetasol caused a reduction in the mononuclear leukocyte numbers. In general, the data suggest that the extract was safe in healthy rodents but indicate that caution should be taken with the photosensitizing activity; in addition, this activity should be further explored as it may be useful for phototherapeutic drug development.

Using therapeutic ultrasound to promote irritated skin recovery after surfactant-induced barrier disruption

BACKGROUND

Surfactant-induced skin barrier disruption can enhance blood flow and water content in the superficial skin. The effect of therapeutic ultrasound on accelerating the recovery of superficial skin after skin barrier disruption has seldom been studied.

OBJECTIVE

To understand the effects of therapeutic ultrasound on barrier recovery, we used the sodium lauryl sulfate irritation model and treatment with ultrasound intervention.

METHODS

The study allocated 30 healthy subjects into an ultrasound group (n = 15) and a control group (n = 15), each divided into three subgroups (sodium lauryl sulfate at concentrations of 1.0%, 0.5%, and 0%). Pulsed ultrasound (1 MHz, 0.3 W/cm²_SATA) was applied to ultrasound subgroups. The treatment effect was evaluated by the recovery rate of enhanced blood flow and water content.

RESULTS

The results indicated a surfactant dose-dependent effect on blood flow, but not on water content. The recovery rates of enhanced blood flow were higher in the 0.5% and 1.0% ultrasound subgroups than in the control subgroups throughout the experiment. However, recovery rates of water content were higher in the ultrasound subgroups than in the control subgroups only on Day2.

CONCLUSIONS

Pulsed ultrasound accelerated the barrier recovery by reducing the enhanced blood flow and water content after skin barrier disruption.

Synthesis and evaluation of topical hydrogel membranes; a novel approach to treat skin disorders

The aim of the study was to synthesize and evaluate chitosan-based topical cross-linked hydrogel membranes of mupirocin for new pharmaceutical controlled release application. These cross-linked structured membranes were synthesized by modification of free radical polymerization. Low molecular weight (LMW) chitosan is cross-linked with 2-acrylamido-2-methylpropane sulfonic acid (AMPS) with a crosslinker N,N-methylenebisacrylamide (MBA). Hydrogel membranes were characterized by FTIR, DSC, TGA, SEM, Swelling behavior, sol-gel analysis, in vitro percent drug release at different pH, permeation across skin, ex vivo drug deposition study, irritation study and in vivo antibacterial activity of mupirocin loaded hydrogels. Developed membranes were spherical, adhesive and have good elastic strength. FTIR confirmed the cross-linking and formation of new structure having appropriate characteristics needed for controlled release delivery system. Drug release through rabbit's skin was evaluated by Franz diffusion cell and up to 6329.61 µg/1.5 cm² was permeated and drug deposition in skin revealed significant retention up to 1224 µg/1.5 cm². Formulated membranes were nonirritant to the skin as validated by Draize patch test. In surgical wound model, LMW chitosan-based hydrogel membranes showed prolong efficacy against bacterial infection caused by S. aureus. Enhanced retention of drug in skin demonstrated the good potential of topical delivery for skin bacterial infection.

Development of an effective and safe topical anti-inflammatory gel containing Jatropha gossypiifolia leaf extract: Results from a pre-clinical trial in mice

ETHNOPHARMACOLOGICAL RELEVANCE

Jatropha gossypiifolia L. (Euphorbiaceae) is a medicinal plant widely used in traditional medicine as an anti-inflammatory remedy. The topical use of the leaves and/or aerial parts of this plant as anti-inflammatory, analgesic, wound healing and anti-infective in several skin diseases is a common practice in many countries. The use of baths or dressings with this vegetal species is frequently reported in folk medicine.

AIM OF THE STUDY

To evaluate the topical anti-inflammatory of aqueous extract from leaves of J. gossypiifolia and to develop a safe and effective herbal gel with anti-inflammatory potential.

MATERIAL AND METHODS

First, the topical acute anti-inflammatory activity of J. gossypiifolia extract was evaluated in ear edema induced by single application of croton oil in mice. Then, a polaxamer-based gel containing J. gossypiifolia extract was developed, physicochemically characterized and evaluated in the same model of inflammation to assess whether the extract incorporation in gel would affect its anti-inflammatory potential. The best formulation was then assayed in ear edema induced by multiple applications of croton oil in mice, to evaluate its chronic anti-inflammatory potential. Inflammatory parameters evaluated included edema, nitrite concentration, mieloperoxidase (MPO) activity and oxidative damage in lipids and proteins. Finally, dermal irritation/corrosion test in mice was performed to access the safeness of the developed gel. Phytochemical characterization of J. gossypiifolia extract was performed by high performance liquid chromatography with diode array detector (HPLC-DAD) analysis.

RESULTS

J. gossypiifolia showed significant acute anti-inflammatory activity in ear edema model, and this activity was significantly increased when equivalent amounts of extract was applied incorporated in the developed polaxamer gels. The gels containing different amounts of extract reduced significantly the levels of edema, nitrite and MPO enzyme in mice ears, with intensity similar to the anti-inflammatory standard drug dexamethasone. The gel containing 1.0% of extract was further evaluated and also showed significant anti-inflammatory activity in chronic inflammation test, reducing significantly ear edema, lipid peroxidation and depletion of reduced glutathione, similarly to dexamethasone. Placebo formulation as well as gel containing extract showed pH compatible to that of human skin and exhibited absence of signs of toxicity in mice, indicating the safeness of the developed product for topical use. HPLC analysis confirmed the presence of C-glycosylflavonoids (orientin, isoorientin, vitexin and isovitexin) as the major compounds of J. gossypiifolia aqueous leaf extract.

CONCLUSIONS

The results demonstrate the potentiality of J. gossypiifolia gel as a promising safe and effective topical anti-inflammatory agent for treatment of cutaneous inflammatory diseases.

Antipsoriatic effect of fatty acid enriched fraction of Vernonia anthelmintica Willd. fruits

ETHNOPHARMACOLOGICAL RELEVANCE

Vernonia anthelmintica has been utilized conventionally as an ingredient in Ayurveda and traditional Uighur medicine for management of various skin ailments, and scientific data's have substantiated its use in treating vitiligo, dermatosis and leucoderma. The present investigation was focused to evaluate the antipsoriatic activity of V. anthelmintica fruit extracts and fractions.

MATERIALS AND METHODS

Ointment containing dichloromethane (DCM) and methanol (MeOH) extracts at topical dose of 2.5% and 5% (w/w) was evaluated using mouse tail model of psoriasis. Bioactivity-guided fractionation (F₁-F₇) of most active extract was carried out and fractions were again subjected to mouse tail model. Further the activity of bioactive fraction was confirmed in HaCaT (human keratinocyte) cell line using MTT (3-(4,5-dimethylthiazol-2-yl)- 2,5-diphenyltetrazolium bromide) assay and its chemical characterization was done via gas chromatography mass spectrometry (GC-MS).

RESULTS

The dichloromethane extract (5%, w/w) showed statistically significant (* p < 0.05) antipsoriatic activity (66.97 ± 2.68%) with respect to control (25.45 ± 1.80%) and equivalent to that of the standard drug, retino-A 0.05%, (72.47 ± 2.14%) in terms of degree of orthokeratosis, whereas methanol extract (5%, w/w) showed significant (* p < 0.05) differentiation (45.86 ± 2.02%) in comparison to the control group. Out of all fractions, F₆ showed statistically significant (* p < 0.05) antipsoriatic activity (69.27 ± 2.76%) with respect to control and equivalent to that of the standard. F₆ (15.6-1000 µg/ml) showed dose-dependent inhibition of HaCaT cell lines proliferation which suggests keratinocyte modulating activity of V. anthelmintica. Chemical characterization of F₆ revealed that essential fatty acids (i.e., linoleic acid, palmitic acid, oleic acid and stearic acid) formed the bulk of bioactive fraction.

CONCLUSION

Ameliorative effect of V. anthelmintica in psoriasis might be attributed to the presence of essential fatty acids and thus corroborates its traditional use in the treatment of skin ailments.

Antimelanogenic Effects of Polygonum tinctorium Flower Extract from Traditional Jeju Fermentation via Upregulation of Extracellular Signal-Regulated Kinase and Protein Kinase B Activation

This study was carried out to investigate the antimelanogenic effects of a Polygonum tinctorium flower extract obtained using red nuruk, a traditional Jeju barley-based fermentation starter. We also studied the mechanism of action of the P. tinctorium fermented flower extract (PTFFE) in mouse melanoma cells (B16F10). Cells were treated with various concentrations (62.5, 125 and 250 μg/mL) of PTFFE and the results showed that PTFFE significantly decreased the melanin content and tyrosinase activity without being cytotoxic. In addition, PTFFE strongly inhibited the expression of tyrosinase and tyrosinase-related protein 2 by decreasing the expression of the microphthalmia-associated transcription factor, as shown by a western blot assay. Furthermore, PTFFE inhibited melanogenesis via upregulation of the phosphorylation of extracellular signal-regulated kinase (ERK) and protein kinase B, also known as AKT. We also used inhibitors such as PD98059 (a specific ERK inhibitor) or LY294002 (an AKT inhibitor) to determine whether the signaling pathways are involved. High-performance liquid chromatography fingerprinting showed the presence of a quercetin glucoside (isoquercitrin) and quercetin in PTFFE. To test the potential for PTFFE application as a cosmetic material, we also performed a primary skin irritation test on human skin. In this assay, PTFFE did not induce any adverse reactions at the treatment dose. Based on these results, we suggest that PTFFE may be considered a potential antimelanogenesis candidate for topical applications.

Pivotal role of Acitretin nanovesicular gel for effective treatment of psoriasis: ex vivo-in vivo evaluation study

The goal of the current study was to explore the potential benefits of Acitretin (Act) nanovesicular gel as a prospective antipsoriatic topical delivery system counteracting the drug challenges in terms of its extremely low aqueous solubility, instability, skin irritation, and serious systemic adverse effects. Act-loaded niosomes were successfully developed, entirely characterized, and optimized. Further evaluation of the optimized formula was conducted regarding its stability and ex vivo cytotoxicity on different cell lines. The optimized niosomal vesicles were then incorporated in gel base matrix and investigated by sequential ex vivo (skin permeation and deposition) and in vivo (skin irritation and antipsoriatic activity using mouse tail model) experiments. The optimized Act-loaded niosomes (span 60:cholesterol molar ratio 1:1) were spherical in shape and exhibited the highest entrapment efficiency (90.32±3.80%) with appropriate nanosize and zeta potential of 369.73±45.45 nm and -36.33±1.80 mV, respectively. Encapsulation of the drug in the nanovesicles was further emphasized by differential scanning calorimetric and powder X-ray diffraction studies. After 3 months storage at 4±1°C, the optimized formula preserved its stability. Act nano niosomal gel produced a remarkable enhanced ex vivo permeation profile up to 30 h and significant drug deposition in the viable epidermal-dermal layers compared with those of Act gel. The pronounced antipsoriatic activity of the medicated nano niosomes was proved ex vivo in HaCaT cells (a keratinocyte cell line). Topical application of Act nano niosomal gel to mouse tail model further established its distinct in vivo antipsoriatic superiority in terms of significantly higher orthokeratosis, drug activity, and reduction in epidermal thickness compared with the control and other gel formulations. Also, negligible skin irritation and better skin tolerability of Act nanovesicular gel were revealed by primary irritation index and histopathologic examination.

The essential oil from Citrus limetta Risso peels alleviates skin inflammation: In-vitro and in-vivo study

ETHNOPHARMACOLOGICAL RELEVANCE

Citrus fruit peels are traditionally used in folk medicine for the treatment of skin disorders but it lacks proper pharmacological intervention. Citrus limetta Risso (Rutaceae) is an important commercial fruit crops used by juice processing industries in all continents. Ethnopharmacological validation of an essential oil isolated from its peels may play a key role in converting the fruit waste materials into therapeutic value added products.

AIM OF THE STUDY

To evaluate the chemical and pharmacological (in-vitro and in-vivo) profile of essential oil isolated from Citrus limetta peels (Clp-EO) against skin inflammation for its ethnopharmacological validation.

MATERIALS AND METHODS

Hydro-distilled essential oil extracted from Citrus limetta peels (Clp-EO) was subjected to gas chromatography (GC) analysis for identification of essential oil constituents and its anti-inflammatory evaluation through in vitro and in vivo models.

RESULTS

Chemical fingerprint of Clp-EO revealed the presence of monoterpene hydrocarbon and limonene is the major component. Pre-treatment of Clp-EO to the macrophages was able to inhibit the production of pro-inflammatory cytokines (TNF-α, IL-6, IL-1β) in LPS-induced inflammation as well as the production of reactive oxygen species (ROS) in H₂O₂-induced oxidative stress. In in-vivo study, topical application of Clp-EO was also able to reduce the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ear thickness, ear weight, lipid peroxidation, pro-inflammatory cytokines production and ameliorate the histological damage in the ear tissue. In-vitro and in-vivo toxicity study indicate that it is safe for topical application on skin.

CONCLUSION

These findings suggested the preventive potential of Clp-EO for the treatment of inflammation linked skin diseases.

Epidermal Penetration of Gold Nanoparticles and Its Underlying Mechanism Based on Human Reconstructed 3D Episkin Model

Nanomaterials are widely used in diverse aspects, and their translocation behavior through the skin would be helpful in understanding the corresponding exposure risks. To reveal how surface functionalization of nanoparticles influences the skin penetration, three kinds of gold nanoparticles (GNPs) with negatively, neutrally, and positively charged surfaces, that is, cetyltrimethylammonium bromide-coated GNPs (CTAB@GNP), polyvinylpyrrolidone-coated GNPs (PVP@GNP), and citrate-coated GNPs (Citrate@GNP), were studied using human reconstructed 3D Episkin model. The measurement of Au distribution in diverse layers of the Episkin model indicated that all three GNPs could penetrate through the epidermis, wherein CTAB@GNP with positive surface charges exhibited the highest efficiency in skin penetration. The upward osmosis of the medium proteins confirmed the occurrence of skin permeation induced by GNP treatment, and the lipid network in the stratum corneum was also altered as the consequence of GNP exposure. When compared to Citrate@GNP and PVP@GNP, CTAB@GNP significantly compromised the tight junction of keratinocytes, causing paracellular penetration of nanoparticles. The existence of cytoplasmic gold showed the transcytosis pathway through endocytosis and exocytosis processes was the main epidermic penetration behavior of the tested GNPs. The study on GNP penetration process through the 3D Episkin model has, on one hand, offered a promising approach to evaluate the translocation process of nanoparticles across the skin, and, on the other hand, provided mechanism explanation for diverse penetration behaviors of GNPs with different surface charges. The findings herein would be of great help in nanotechnology improvement and nanosafety evaluation.

2,4-Dinitroanisole (DNAN) (2014)

2,4-dinitroanisole (DNAN) is a warhead explosive currently under investigation as a replacement for TNT in melt-cast insensitive munitions. In animal studies, DNAN is a mild ocular and skin irritant with a significant potential for dermal absorption.  It is not a dermal sensitizer.  Acute and subacute rat inhalation studies demonstrated minimal toxicity with LC₅₀ and LOAEL endpoints of 2.9 and 150 mg/m³, respectively.  In rat oral toxicity studies (14 and 90 days) organ weight and clinical chemistry changes suggested hepatocellular injury and anemia, particularly in females.  In males there was evidence of testicular injury at the high-dose level (80 mg/kg/day).  The NOAELs for the 14- and 90-day studies were 25 and 5 mg/kg/day, respectively, with a calculated BMDL₁₀ value of 0.93 mg/kg/day.  No chronic, carcinogenicity or reproductive/developmental toxicity data were available for DNAN, but a maternal and fetal NOAEL of 5.1 mg/kg/day was inferred.  DNAN is considered non-mutagenic and non-genotoxic.  It is metabolized in vivo to 2,4-dinitrophenol (DNP), but other details of its metabolism or pharmacokinetics are unknown.  There are considerable toxicity data for DNP, a known un-coupler of oxidative phosphorylation among other things, and these data may further inform regarding the safety of DNAN.  In humans, DNAN was a component of louse powder (prior to DDT) with no reported safety concerns.  However, its handling and use as a munition component presents a potential occupational hazard by both inhalation and dermal routes of exposure.  Considering both DNAN and DNP toxicity endpoints, the recommended Workplace Environmental Exposure limit for DNAN is 0.1 mg/m² (8-h time weighted average).

Formulation design and in vitro ex vivo evaluation of transdermal patches of Cinnarizine

The aim of this study was to develop a Transdermal patch containing Cinnarizine using different ratios of hydrophilic and hydrophobic polymeric systems by solvent evaporation technique employing Polyethylene glycol (PEG 400) as plasticizer. The physicochemical compatibility of the drug and the polymers were studied by performing FT-IR spectroscopic analysis. Formulated patches were evaluated for physicochemical properties, skin irritation, in vitro drug release, ex-vivo permeation studies across rat abdominal skin and stability studies. The results of FT-IR studies revealed that there were no interactions between drug and polymers used. All the formulations exhibited uniformity in physicochemical properties. In vitro permeation studies of the formulations were performed by using Franz diffusion cells. Formulation F3 showed better permeation through rat skin (i.e., 8527.5±1.25μ/cm2 /hr) compared to rest of formulations and followed Fick's diffusion mechanism. On the basis of in-vitro drug release and ex-vivo skin permeation performance, Formulation F3 containing the polymeric blend 19:1 Hydroxypropylmethyl Cellulose (HPMC E 50cps: Eudragit RL 100) has shown optimum release in comparison to other formulations and indicated good physical stability. So it has been demonstrated that Cinnarizine can be designed as matrix type transdermal drug delivery system (TDDS) and further in-vivo evaluations were required.

Jasmine rice panicle: A safe and efficient natural ingredient for skin aging treatments

ETHNOPHARMACOLOGICAL RELEVANCE

While rice is one of the most important global staple food sources its extracts have found many uses as the bases of herbal remedies. Rice extracts contain high levels of phenolic compounds which are known to be bioactive, some of which show cutaneous benefits and activity towards skin disorders. This study highlights an assessment of the cellular activity and clinical efficacy of rice panicle extract, providing necessary information relevant to the development of new cosmetic products.

MATERIALS AND METHODS

Jasmine rice panicle extract was standardized, and the level of phenolics present was determined. In vitro anti-aging, and extract activity towards melanogenesis was conducted in B16F10 melanoma cells, and antioxidant activity was assessed in human skin fibroblast cell cultures. Topical product creams containing the extract were developed, and skin irritation testing using a single application closed patch test method was done using 20 Thai volunteers. Randomized double-blind, placebo-controlled efficacy evaluation was undertaken in 24 volunteers over an 84d period, with the results monitored by Corneometer^® CM 825, Cutometer^® MPA 580, Mexameter^® MX 18 and Visioscan^® VC 98.

RESULTS

Jasmine rice panicle extract was shown to have a high content of p-coumaric, ferulic and caffeic acids, and was not cytotoxic to the cell lines used in this study. Cells treated with extract suppressed melanogenesis via tyrosinase and TRP-2 inhibitory effects, which protect the cell from oxidative stress at doses of 0.1mg/ml or lower. The jasmine rice panicle preparations (0.1-0.2%) were safe (MII=0), and significantly (p<0.05) increased skin hydration levels relative to baseline. Skin lightening, and anti-wrinkle effects related to skin firmness and smoothness were observed, in addition to a reduction in skin wrinkling. Improvements in skin biophysics of both 0.1% and 0.2% extracts were showed to be comparable (p>0.05).

CONCLUSIONS

Jasmine rice panicle extract having high levels of phenolics shows cutaneous benefits as the basis for skin aging treatments, as indicated through in vitro cytotoxicity assessments and skin testing in human subjects.

Skin Sensitization: Modeling Based on Skin Metabolism Simulation and Formation of Protein Conjugates

A quantitative structure-activity relationship (QSAR) system for estimating skin sensitization potency has been developed that incorporates skin metabolism and considers the potential of parent chemicals and/or their activated metabolites to react with skin proteins. A training set of diverse chemicals was compiled and their skin sensitization potency assigned to one of three classes. These three classes were, significant, weak, or nonsensitizing. Because skin sensitization potential depends upon the ability of chemicals to react with skin proteins either directly or after appropriate metabolism, a metabolic simulator was constructed to mimic the enzyme activation of chemicals in the skin. This simulator contains 203 hierarchically ordered spontaneous and enzyme controlled reactions. Phase I and phase II metabolism were simulated by using 102 and 9 principal transformations, respectively. The covalent interactions of chemicals and their metabolites with skin proteins were described by 83 reactions that fall within 39 alerting groups. The SAR/QSAR system developed was able to correctly classify about 80% of the chemicals with significant sensitizing effect and 72% of nonsensitizing chemicals. For some alerting groups, three-dimensional (3D)-QSARs were developed to describe the multiplicity of physicochemical, steric, and electronic parameters. These 3D-QSARs, so-called pattern recognition-type models, were applied each time a latent alerting group was identified in a parent chemical or its generated metabolite(s). The concept of the mutual influence amongst atoms in a molecule was used to define the structural domain of the skin sensitization model. The utility of the structural model domain and the predictability of the model were evaluated using sensitization potency data for 96 chemicals not used in the model building. The TIssue MEtabolism Simulator (TIMES) software was used to integrate a skin metabolism simulator and 3D-QSARs to evaluate the reactivity of chemicals thus predicting their likely skin sensitization potency.

Final Report on the Safety Assessment of Malic Acid and Sodium Malate

Malic Acid functions in cosmetic formulations as a pH adjuster, and Sodium Malate functions as a skin conditioning agent-humectant. Malic Acid is reportedly used in almost 50 cosmetic formulations across a range of product types at low concentrations, whereas Sodium Malate is used in only one. As a pH adjuster, Malic Acid is used at low concentrations. One commercial method of preparing Malic Acid is hydration of fumaric acid or maleic acid, and then purified to limit the amount of the starting material present. Because Malic Acid is a component of the Kreb's cycle, another method is fermentation. Malic Acid was relatively nontoxic in acute toxicity studies using animals. In a chronic oral study, feeding Malic Acid to rats resulted only in weight gain changes and changes in feed consumption. Malic Acid did not cause reproductive toxicity in mice, rats, or rabbits. Malic Acid was a moderate to strong skin irritatant in animal tests, and was a strong ocular irritant. Malic Acid was not mutagenic across a range of genotoxicity tests. Malic Acid was irritating in clinical tests, with less irritation seen as pH of the applied material increased. Patients patch tested with Malic Acid, placed on a diet that avoided foods containing Malic or citric acid, and then challenged with a diet high in Malic and citric acid had both immediate urticarial and delayed contact dermatitis reactions. These data were considered sufficient to determine that Malic Acid and Sodium Malate would be safe at the low concentrations at which these ingredients would be used to adjust pH (even though Sodium Malate is not currently used for that purpose). The data, however, were insufficient to determine the safety of these ingredients when used in cosmetics as other than pH adjusters and specifically, the data are insufficient to determine the safety of Sodium Malate when used as a skin conditioning agent-humectant. The types of data required for the Expert Panel to determine the safety of Sodium Malate as a skin-conditioning agent are: concentration of use data; dermal irritation and sensitization data; and ocular irritation data, if available. The data needed to assess the safety of Malic Acid or Sodium Malate for some function other than as a skin-conditioning agent cannot be specified without knowing the intended function. Were these ingredients to be used as exfoliants, for example, data similar to that included in the Cosmetic Ingredient Review safety assessment of Glycolic Acid would be needed. Until these data are available, it is concluded that the available data are insufficient to support the safety of these ingredients in cosmetic formulations for functions other than use as a pH adjuster.

Final Report on the Safety Assessment of Corylus Avellana (Hazel) Seed Oil, Corylus Americana (Hazel) Seed Oil, Corylus Avellana (Hazel) Seed Extract, Corylus Americana (Hazel) Seed Extract, Corylus Rostrata (Hazel) Seed Extract, Corylus Avellana (Hazel) Leaf Extract, Corylus Americana (Hazel) Leaf Extract, and Corylus Rostrata (Hazel) Leaf Extract

These ingredients are all derived from hazelnut trees. The two seed oils are expressed from the nuts of the hazelnut tree of the particular species identified. Most current reported cosmetic uses are of the seed oils. The seed extracts are the extract of the nuts of the identified species tree. There is one current report of use of seed extract in cosmetics. The leaf extracts are the extract from the leaves of the particular species tree. There are no current reports of use of these extracts in cosmetics. Analysis of seed oil from one species identified Oleic Acid, Palmitoleic Acid, Linoleic Acid, Eicosaenoic Acid, Docosenoic Acid, Eicosanoic Acid, Palmitic Acid, Linolenic Acid, Stearic Acid, and Tetraeicosanoic Acid. Little information is available to characterize the extracts, however. The functions of most of these ingredients in cosmetics are not reported. In studies of hazelnuts from Spain and Egypt, aflatoxin was reported as a possible contaminant. Aflatoxins are considered carcinogenic in humans. Virtually no safety test data are available on these ingredients. Negative results in one comedogenicity study using a seed oil are reported. Cross-sensitivity to proteins in peanuts and those in hazelnuts are reported, but the presence or absence of protein in nut extract and plant extract from hazelnut trees is not known. Additional data were provided regarding concentration of use, method of extraction and contaminants, comedogenicity, and ultraviolet (UV) radiation absorption, but these data related to nut oil from only one species, and were not overall sufficient to resolve questions about irritation, sensitization, and photosensitization. Because of the absence of data, it is concluded that the available data are insufficient to support the safety of these ingredients in cosmetic products. Because of the limited information that characterizes any of these oils or extracts, data are needed on each (except that items 1, 2, and 3 below are not needed for Hazel [Corylus Avellana] Nut Oil). The additonal data needs include: (1) current concentration of use; (2) method of extraction/manufacture and quality control (i.e., chemical analyses); (3) contaminants and methods of extraction (especially pesticides and heavy metals); (4) dermal irritation and sensitization; (5) UV absorption; if there is significant absorption, then a photosensitization study will be needed; (6) 28-day dermal toxicity; (7) reproductive and developmental toxicity; and (8) two genotoxicity assays, one in a mammalian system; if positive, then a 2-year dermal carcinogenesis study using National Toxicology Program (NTP) methods may be needed.

Safety assessment of a traditionally used extract from leaves of Boldoa purpurascens

ETHNOPHARMACOLOGICAL RELEVANCE

Boldoa purpurascens Cav. (Nyctaginaceae) is a plant species used in traditional medicine in Cuba as a diuretic.

AIM OF THE STUDY

The aim of the present investigation was to evaluate the safety profile of a hydroalcoholic extract from leaves of Boldoa purpurascens.

MATERIALS AND METHODS

First, an experimental study to assess the oral acute toxicity at a dose of 2000mg/kg body weight of the extract was carried out. Potential genotoxicity of the extract was evaluated using the Ames test and the micronucleus induction assay in mouse bone marrow. In the Ames test a concentration range of 50, 100, 150, 300 and 500µg/plate was tested. In the micronucleus induction assay, doses of 500, 1000 and 2000mg/kg of body weight were tested. For completeness, since the extract contains saponins, the evaluation of the hemolytic activity, ocular and skin irritation were included.

RESULTS

No signs or symptoms of toxicity were observed in the oral acute toxicity test (body weight at baseline, seven days and end of the experiment of 236.41±20.07, 256.81±30.44 and 240.02±26.16 respectively for the treated group). The hydroalcoholic extract from the leaves was not mutagenic in the Ames test, and no genotoxicity was observed in the micronucleus assay. A hemolysis test at concentration of 1mg/mL confirmed hemolytic activity, which is not a safety concern since saponins are not absorbed after oral administration. In order to evaluate the percentage of protein denaturation, the ocular irritability index was calculated. The extract was found to be irritating. Finally, skin irritability was evaluated and the irritation index was equal to zero.

CONCLUSIONS

Based on the toxicological evaluation of a traditionally used hydroalcoholic extract from the leaves of Boldoa purpurascens we can confirm the safety of its oral use.

SEEQ™ MCT wearable sensor performance correlated to skin irritation and temperature

The Medtronic SEEQ(™) Mobile Cardiac Telemetry System provides continuous monitoring of symptomatic and asymptomatic cardiac arrhythmias. Deployed across disparate geographies, the device and the patients wearing it are subject to a wide range of weather conditions, specifically differing temperatures. We hypothesized that extremes of temperature would result in degradation of SEEQ system performance due to patient discomfort, perspiration, and other factors. Towards that end, we investigated data from over 5000 devices worldwide, including those linked to patient complaints for discomfort. We found that the data does not show a degradation of wearable performance as defined by artifact or event rate with temperature. However, there was a correlation between patient complaints of discomfort and degraded performance as well as a weak correlation with reduced system longevity at temperatures above 80° F.

Catch-up validation study of an in vitro skin irritation test method based on an open source reconstructed epidermis (phase I)

We have developed a new in vitro skin irritation test based on an open source reconstructed epidermis (OS-REp) with openly accessible protocols for tissue production and test performance. Due to structural, mechanistic and procedural similarity, a blinded catch-up validation study for skin irritation according to OECD Performance Standards (PS) was conducted in three laboratories to promote regulatory acceptance, with OS-REp models produced at a single production site only. While overall sensitivity and predictive capacity met the PS requirements, overall specificity was only 57%. A thorough analysis of the test results led to the assumption that some of the false-positive classifications could have been evoked by volatile skin-irritating chemicals tested in the same culture plate as the non-irritants falsely predicted as irritants. With GC/MS and biological approaches the cross-contamination effect was confirmed and the experimental set-up adapted accordingly. Retesting of the affected chemicals with the improved experimental set-up and otherwise identical protocol resulted in correct classifications as non-irritants. Taking these re-test results into account, 93% overall sensitivity, 70% specificity and 82% accuracy was achieved, which is in accordance with the OECD PS. A sufficient reliability of the method was indicated by a within-laboratory-reproducibility of 85-95% and a between-laboratory-reproducibility of 90%.

Pereskia aculeata Miller leaves present in vivo topical anti-inflammatory activity in models of acute and chronic dermatitis

ETHNOPHARMACOLOGICAL RELEVANCE

The leaves of Pereskia aculeata Miller (Cactaceae), known as Barbados gooseberry, are used in Brazilian traditional medicine as emollients and to treat skin wounds and inflammation. This study investigated the topical anti-inflammatory activity of the hexane fraction (HF) obtained from the methanol extract of the leaves of this species in models of acute and chronic ear dermatitis in mice.

MATERIAL AND METHODS

Mice ear edema was induced by topical application of croton oil, arachidonic acid, capsaicin, ethyl-phenylpropiolate and phenol; and by subcutaneous injection of histamine. Ear biopsies were obtained to determine the levels of IL-1β, IL-6 and TNF-α cytokines by ELISA assay. Histopathological analysis was also performed to evaluate the HF activity in croton oil multiple application test. In addition, acute dermal irritation/corrosion test in rats was accomplished. HF chemical characterization was performed by GC-MS analysis.

RESULTS

HF intensively reduced the inflammatory process induced by all irritant agents used, except for arachidonic acid. This activity is related, at least in part, to the reduction of IL-6 and TNF-α cytokines levels. Moreover, when the glucocorticoid receptor antagonist mifepristone was used, HF failed to respond to the croton oil application.The results strongly suggested a glucocorticoid-like effect, which was reinforced by the presence of considerable amounts of sterol compounds identified in HF. The acute dermal irritaton/corrosion test showed no signs of toxicity.

CONCLUSIONS

This study showed that the acute and chronic anti-inflammatory activity of P. aculeata leaves is very promising, and corroborates to better understand their ethnopharmacological applications.

Design and Characterization of Silicone and Surfactant Based Systems for Topical Drug Delivery

Nanotechnology offers advantages for new drug delivery design by providing drug targeting while minimizing the side effects. Polyoxyethylene 20 cetyl alcohol (CETETH-20) is a surfactant that may form nanostructured systems, such as liquid crystals, when in contact with water/oil, which are structurally similar to biological membranes and may improve skin interaction. The aim of this study was to develop and characterize CETETH 20-based nanostructured systems by combining CETETH-20 with water and different oily phases, including PEG-12-dimethicone for topical drug administration. The systems were characterized by polarized light microscopy (PLM), small-angle X-ray scattering (SAXS), rheology, texture profile analyses (TPA), in vitro cytotoxicity and histopathological analyses of rabbits' skin. Lamellar, hexagonal and cubic phases were identified and their viscoelastic moduli varied according to each phase. The stiffness of the cubic phase was 3-fold higher and twice more adhesive than the hexagonal phase. The formulations did not affect the normal macrophages cells, neither promoted skin irritation. They were spontaneously obtained by simply mixing the components, which corroborates for an ease scaled-up. These results suggest that systems composed of CETETH 20, PEG-12-dimethicone and water are a promising new approach for designing nanostructured topical drug delivery systems.

Predictability of in vitro dermal assays when evaluating fatty amine derivatives

It is widely accepted that skin assays based on reconstructed human epidermis (RhE) models can be used in place of in vivo testing to accurately predict corrosivity and/or irritancy of commodity chemicals. Due to REACH legislation, substances from various categories of fatty amines derivatives have been evaluated for dermal corrosion applying either the EpiDerm™ (EPI-200) or EpiSkin™ assay. Available data and practical experience indicated that these substances are corrosive to the skin. The substances tested are cationic surfactants which dermal effects are characterized by a delayed severe inflammatory reaction. The mechanism is thought to be related to disruption of the cellular membrane following diffusion of the long apolar tails of the molecules into the lipid bilayers. However, unexpectedly almost all obtained study results indicated that these substances are NOT corrosive in these in vitro RhE test systems. Since these results did not align with the experiences on such substances, limited in vivo rabbit studies were employed additionally. These studies confirmed that after some delay full skin tissue destruction occurs, requiring classification as Corrosive Cat.1B or 1C for GHS. The results obtained for various fatty amine derivatives shows that RhE assays do not always predict corrosivity correctly.

Skin barrier integrity and natural moisturising factor levels after cumulative dermal exposure to alkaline agents in atopic dermatitis

Dermal exposure to alkaline agents may lead to skin barrier damage and irritant contact dermatitis. The objective of this study was to investigate the effects of cumulative exposure to 0.5% sodium lauryl sulphate (SLS) and 0.15% NaOH on the barrier function and natural moisturising factor (NMF) levels in atopic dermatitis and healthy volunteers with known filaggrin genotype. The skin response was monitored by measurement of erythema and transepidermal water loss. The stratum corneum NMF levels were determined by high-performance liquid chromatography. Repeated exposure to 0.5% SLS and/or 0.15% NaOH in atopic dermatitis resulted in more severe impairment of the skin barrier function. Cumulative exposure to the irritants reduced significantly NMF in both the atopic and healthy controls group. The pronounced decrease of NMF after repeated single and sequential irritant exposure may be a pathogenetically relevant factor for development of chronic irritant contact dermatitis in both healthy and atopic individuals.

Protective effects of a new phloretin derivative against UVB-induced damage in skin cell model and human volunteers

The phenolic compound phloretin is a prominent member of the chemical class of dihydrochalcones. Phloretin is specifically found in apple and apple juice and known for its biological properties. We were particularly interested in its potential dermo-cosmetic applications. However, practical limitations of phloretin do exist due to its poor water-solubility. Phloretin was sulfonated with sulfuric acid (98%, wt) and mixed with saturated salt water to produce phloretin 3',3-disulfonate in order to increase its water-solubility. Here we reported the photoprotective effect of phloretin 3',3-disulfonate (PS), a new semi-synthetic derivative of phloretin. Results showed that PS attenuated cyclobutane pyrimidine dimer (CPDs) formation, glutathione (GSH) depletion and apoptosis induced by ultraviolet B (UVB). The photoprotective effect of PS is tightly correlated to the enhancement of nucleotide excision repair (NER) gene expression. Furthemore, PS had inhibitory effects on UVB-induced release of the inflammatory mediators, such as IL-6 and prostaglandin-E2. We also confirmed the safety and clinical efficacy of PS on human skin. Overall, the results demonstrated significant benefits of PS on the protection of keratinocytes against UVB-induced injuries and suggested its potential use in skin photoprotection.

Patch testing with formaldehyde 2.0% in parallel with 1.0% by the Swedish contact dermatitis research group

In a multicentre study consecutively patch-tested dermatitis patients were tested simultaneously with 1.0% and 2.0% (w/v) formaldehyde in aqua applied with a micropipette (15 µl) to the filter paper disc in Finn Chambers (0.30 mg/cm(2) and 0.60 mg/cm(2), respectively). A total of 2,122 dermatitis patients were patch-tested. In all, 77 (3.6%) patients reacted positively to formaldehyde; 37 reacted only to 2.0%, 35 reacted to both concentrations and 5 patients reacted only to 1.0%. Significantly more patients were thus diagnosed with contact allergy to formaldehyde with 2.0% compared to 1.0% (p < 0.001) without causing more irritant reactions. The detected number of isolated allergic reactions to the 2 formaldehyde-releasers in the Swedish baseline series and not to formaldehyde itself raises the question whether quaternium-15 1.0% and diazolidinyl urea 2.0% should be present in the Swedish baseline series.

Development and characterization of a novel antiacne niosomal gel of rosmarinic acid

The antibacterial and anti-inflammatory potential of rosemarinic acid (ROA), a naturally occurring ester of caffeic acid has been well reported. Antibacterial effect of ROA is attributed to nucleoid damage with an increase in spatial division and condensation of genetic material. ROA has been found dynamic against many human pathogenic bacterial strains but its inhibitory prospective has never been established against skin inflammations caused by Propionibacterium acne. The skin surface in acne prone areas is colonized with Staphylococcus aureus and Propionibacterium acnes which contribute to inflammation and acne. Resistance to current antimicrobial therapies suggested the need to explore new antimicrobial agents against acne. Present work included the preparation of ROA-loaded niosomes and their in vitro antimicrobial evaluation against P. acne and S. aureus. This work also included the development of niosomal gel of rosmarinic acid for sustained delivery to bacteria infected cells. Niosomes of rosmarinic acid were formulated by reverse phase evaporation method using different ratio of span 85 and cholesterol. The prepared formulations were evaluated for its vesicle size, entrapment efficiency, in vitro release study and antibacterial activity. In vivo study of developed formulation was conducted on Swiss albino mice in comparison with solution of plain drug and a marketed formulation of benzoyl peroxide. It was evident that niosomes are novel carrier for delivery of naturally occurring antimicrobial agents, in deeper tissues of skin. The results showed that drug-loaded niosomes dispersed in the gelling agent are an effective delivery system for treatment of acne vulgaris.

Topical continuous use of Lippia sidoides Cham. essential oil induces cutaneous inflammatory response, but does not delay wound healing process

ETHNOPHARMACOLOGICAL RELEVANCE

The essential oil of Lippia sidoides (EOLS) has been used in Brazilian folk medicine as a topical antiseptic agent in skin for treatment of wounds and superficial infections of the body. The aim of this study was to investigate the effects of EOLS on intact and damaged skin, including its action on expression of mediators, COX-2 and VEGF, involved in healing full-thickness cutaneous lesions in vivo.

MATERIAL AND METHODS

EOLS was analyzed chemically and used at different concentrations to dose-response experiments in skin mice. Skin irritation tests by one-dosage and multiple-dosages and irritation to damaged skin were assessed by macroscopy, morphometry and histological and immunohistochemical analyses. To evaluate the effects of EOLS on wound healing, excision wounds were surgically created on the dorsum of rats, and the ointments at 6% and 12% were applied daily to the wound area. Cutaneous lesions were assessed by planimetric (wound contraction) and macroscopic parameters.

RESULTS

Skin irritation tests showed that topical application of EOLS promoted cutaneous inflammation in varying degrees, which was demonstrated by increase of skin thickness and formation of cutaneous edema and erythema. Topical administration of EOLS in high concentrations presented an irritant response to skin, but this irritation is lighter when low concentrations this oil were used. Histological evaluation supported the outcome of these models, which revealed accentuated presence of inflammatory cells infiltration. In wound healing process, the lesions treated with EOLS showed intense edema and exsudation up to day 5, but there were not significant differences in the wound contraction on days 14 and 21. No immunohistochemical staining was verified to COX-2 and VEGF mediators in skin treated with EOLS 12%.

CONCLUSION

The continuous application of EOLS in adequate concentrations on cutaneous wounds increases inflammatory response without delay the lesions closure. The association of these results with antimicrobial action previously related to EOLS allows its indication as an alternative therapeutic modality for topical treatment of infected cutaneous wound. Nevertheless, further studies need to be performed to determine the mechanism of action and support its application in clinical practice.

Coumarin derivatives, but not coumarin itself, cause skin irritation via topical delivery

Coumarin and its derivatives are widely employed as a fragrance in cosmetics and skin care products. The skin absorption level and possible disruption to the skin by topical application of coumarins were evaluated in this study. Percutaneous absorption of osthole, daphnoretin, coumarin, byakangelicin, and 7-hydroxycoumarin was assessed in vitro and in vivo. Skin physiology measurements and immunoblotting were utilized as methodologies for validating toxicity. The relationship between structures and permeation/toxicity of coumarins was elucidated. Both equimolar concentration and saturated solubility in 30% ethanol were used as the applied dose. Osthole with the most lipophilic characteristic demonstrated the greatest skin accumulation, followed by coumarin and 7-hydroxycoumarin. Coumarin was the permeant with the highest flux across the skin. The trend of in vivo deposition was consistent with that of the in vitro profiles. Skin uptake of osthole was 8-fold higher than that of coumarin. Hair follicles played a significant role as a pathway for transport of coumarin according to the examination of follicular accumulation. Osthole and 7-hydroxycoumarin slightly, but significantly, enhanced transepidermal water loss after a consecutive 5-day administration. The immunoblotting profiling verified the role of proliferation in skin damage induced by osthole, byakangelicin, and 7-hydroxycoumarin. The proliferation-related proteins examined in this work included glucose-regulated proteins, cytokeratin, and C-myc. Daphnoretin and coumarin showed a negligible alteration on protein biomarkers. The experimental results suggested that skin irritation caused by coumarins was mainly derived from the analogs but not from coumarin itself.

Laundry detergents and skin irritancy--a comprehensive review

Surface-active agents (surfactants) form the foundation of an effective detergent formulation. As such, surfactants are a major component of laundry detergents. Depending on multiple factors, the amount of residual detergent surfactants in clothing after washing varies but may be sufficient to elicit skin irritation in susceptible individuals and in patients with existing dermatologic disorders. The goal of this review is to examine the relationship between surfactants commonly used in laundry detergent formulations and their potential for skin irritancy. In this context, the role of surfactants in achieving broad-spectrum cleaning performance in laundry is discussed, and currently available methodologies to evaluate and measure the effect of surfactant exposure on the skin are reviewed.

Occupational dermatoses caused by contact with metalworking fluids in the region of central slovakia from 2000 to 2012

Metalworking fluids (MWFs) are a common cause of allergic and irritant contact dermatitis. MWFs being currently used are mostly water based, containing biocides, emulsifiers, and other additives. We performed a retrospective analysis of the etiology of the occupational dermatoses caused by metalworking fluids in three regions of Central Slovakia (population of approximately 2 million) between 2000 and 2012. The primary aim was the analysis of metalworking fluid-induced dermatoses, which involved determining the particular disease type (allergic or irritant), its regional distribution, and the specific chemical causing the disease. The secondary aim of the study was to assess the level of knowledge and competence among dermatologists in performing patch testing for allergens contained in metalworking fluids using a study-specific questionnaire. Of the total number of 422 dermatoses during the analyzed period, 64 (41 in men and 23 in women) were caused by metalworking fluids. The implicated fluids were all aqueous, synthetic MWFs. 39 patients developed an allergic and 25 an irritant-induced contact dermatitis. 51 patients were tested using a special Trolab® metalworking battery (Almirall Hermal GmbH, Reinbek, Germany). The test identified a positive reaction to one of the following chemicals: methylchoroisothiazolinone/methylisothiazolinone (MCI/MI), formaldehyde, 1,2-benzisothiazoline-3-one, abietic acid, chloroxylenol, triclosan, amerchol L101, dichlorophene, propylenglycol, metylene (bis-methyl oxazolidine), monoethanolamine, and diethanolamine. The questionnaire showed that a large majority of Slovak dermatologists have no experiences with testing of MWFs. Metalworking fluids were found to be the most frequent cause of occupational contact dermatitis. They also are the second largest group of all occupational dermotoses. Their incidence corresponded with the presence of machine industry in the region. Several unresolved problems include detection of specific allergens and standardization of patch test performance among individual dermatologists. Low levels of experience in testing of MWFs revealed need to educate both dermatologists and residents.

Squarticles as a lipid nanocarrier for delivering diphencyprone and minoxidil to hair follicles and human dermal papilla cells

Delivery of diphencyprone (DPCP) and minoxidil to hair follicles and related cells is important in the treatment of alopecia. Here we report the development of "squarticles," nanoparticles formed from sebum-derived lipids such as squalene and fatty esters, for use in achieving targeted drug delivery to the follicles. Two different nanosystems, nanostructured lipid carriers (NLC) and nanoemulsions (NE), were prepared. The physicochemical properties of squarticles, including size, zeta potential, drug encapsulation efficiency, and drug release, were examined. Squarticles were compared to a free control solution with respect to skin absorption, follicular accumulation, and dermal papilla cell targeting. The particle size of the NLC type was 177 nm; that of the NE type was 194 nm. Approximately 80% of DPCP and 60% of minoxidil were entrapped into squarticles. An improved drug deposition in the skin was observed in the in vitro absorption test. Compared to the free control, the squarticles reduced minoxidil penetration through the skin. This may indicate a minimized absorption into systemic circulation. Follicular uptake by squarticles was 2- and 7-fold higher for DPCP and minoxidil respectively compared to the free control. Fluorescence and confocal images of the skin confirmed a great accumulation of squarticles in the follicles and the deeper skin strata. Vascular endothelial growth factor expression in dermal papilla cells was significantly upregulated after the loading of minoxidil into the squarticles. In vitro papilla cell viability and in vivo skin irritancy tests in nude mice suggested a good tolerability of squarticles to skin. Squarticles provide a promising nanocarrier for topical delivery of DPCP and minoxidil.

Safety assessment and biological effects of a new cold processed SilEmulsion for dermatological purpose

It is of crucial importance to evaluate the safety profile of the ingredients used in dermatological emulsions. A suitable equilibrium between safety and efficacy is a pivotal concern before the marketing of a dermatological product. The aim was to assess the safety and biological effects of a new cold processed silicone-based emulsion (SilEmulsion). The hazard, exposure, and dose-response assessment were used to characterize the risk for each ingredient. EpiSkin assay and human repeat insult patch tests were performed to compare the theoretical safety assessment to in vitro and in vivo data. The efficacy of the SilEmulsion was studied using biophysical measurements in human volunteers during 21 days. According to the safety assessment of the ingredients, 1,5-pentanediol was an ingredient of special concern since its margin of safety was below the threshold of 100 (36.53). EpiSkin assay showed that the tissue viability after the application of the SilEmulsion was 92 ± 6% and, thus considered nonirritant to the skin. The human studies confirmed that the SilEmulsion was not a skin irritant and did not induce any sensitization on the volunteers, being safe for human use. Moreover, biological effects demonstrated that the SilEmulsion increased both the skin hydration and skin surface lipids.

Gene expression changes induced by skin sensitizers in the KeratinoSens™ cell line: Discriminating Nrf2-dependent and Nrf2-independent events

The KeratinoSens™ assay is an in vitro screen for the skin sensitization potential of chemicals. It is based on a luciferase reporter gene under the control of the antioxidant response element of the aldoketoreductase gene AKR1C2. The transferability, reproducibility, and predictivity of the KeratinoSens™ assay have been investigated in detail and it is currently under assessment at the European Center for Validation of Alternatives to animal testing (ECVAM). Here we investigate the sensitizer-induced gene expression in the KeratinoSens™ cell line at the mRNA level and discriminate Nrf2-dependent and Nrf2-independent events by using siRNA to better characterize this test system at the molecular level. The results show that (i) the sensitizer-induced luciferase signal in KeratinoSens™ cells is completely dependent on Nrf2. The same holds true for the luciferase induction observed for the false positive chemical Tween80, indicating that the false positive result is not due to recruitment of an alternative transcription factor. (ii) Luciferase induction parallels the induction of endogenous Nrf2-dependent genes, indicating that the luciferase signal is representative for the sensitizer-induced Nrf2-response. (iii) The induction by sensitizers of additional genetic markers related to heat shock proteins and cellular stress could be reproduced in the KeratinoSens™ cell line and they were shown to be Nrf2-independent. These results confirm that the KeratinoSens™ cell line is a rapid and adequate screening tool to assess the sensitizer-induced Nrf2-response in keratinocytes.

Evaluation of the wound healing activity of Shorea robusta, an Indian ethnomedicine, and its isolated constituent(s) in topical formulation

ETHNOPHARMACOLOGICAL RELEVANCE

Different parts of Indian ethnomedicinal plant Shorea robusta is traditionally used for several ailments including wounds and burn by different tribal groups, since ages. Here we have validated, for the first time, the effectiveness and the possible mechanism of action of young leaf extracts of Shorea robusta, used by two distinct tribes of India, and its isolated compounds as a topical formulation in three wound models in rats.

MATERIALS AND METHODS

Bioactivity-guided study of the active extract resulted in the isolation of two known compounds. The prepared ointment containing extracts (2.5 and 5%, w/w), fractions (5% w/w) and isolated compounds (0.25% w/w) were evaluated on excision, incision and dead space wound models in rats by the rate of wound closure, period of epithelialisation, tensile strength, granulation tissue weight, hydroxyproline content and histopathology.

RESULTS

The animals treated with the extracts and fractions (5%) showed significant reduction in wound area 96.55 and 96.41% with faster epithelialisation (17.50 and 17.86), while the isolated compounds bergenin and ursolic acid heal the wound faster, but complete epithelialisation with 100% wound contraction was evident with 5% povidone-iodine group on 18th post-wounding day. Moreover, the tensile strength of incision wound, granuloma tissue weight, and hydroxyproline content was significantly increased in both the extract and compound(s) treated animals. Furthermore, the tissue histology of animals treated with the isolated compound(s) showed complete epithelialisation with increased collagenation, similar to povidone-iodine group.

CONCLUSION

Thus, our results validated the traditional use of Shorea robusta young leaves in wound management.