Assessing the dermal compatibility of a new female incontinence product line

Context: We have developed a line of products designed to better meet the overall needs of women suffering from urinary incontinence. The products are more discrete and contain a unique odor neutralizing technology (ONT).

Objective: This paper describes the overall skin compatibility program for this product line in which the new products were compared to negative controls and/or commercially marketed reference products with an established history of safe use.

Materials and methods: Test products consisted of several product forms (light pads/pantiliners, moderate pads, briefs and taped diapers) with ONT and having various degrees of protection. Studies were conducted using standard protocols for 4-day and 21-day cumulative irritation, the Human Repeat Insult Patch Test (HRIPT), and the Behind-the-Knee (BTK) test for mechanical and chemical irritation. In one 4-day irritation study and one HRIPT, test subjects consisted of individuals with self-assessed sensitive skin. In addition, one 4-day study was conducted using normal skin sites, and sites compromised by tape stripping. Nonirritant controls were physiologic saline and/or current, commercially marketed incontinence products. All responses were evaluated by visual scoring of erythema. In addition, in the BTK, transepidermal water loss (TEWL) and adverse sensory effects collected from panelists’ daily diaries were also evaluated.

Results and discussion: Two 4-day cumulative irritation studies and one 21-day study demonstrated that a wide range of product forms (liners, light and moderate pads, briefs and adult diapers) produced skin reactions similar to the nonirritant controls. The 4-day study conducted using sensitive skin subjects showed good skin compatibility, and the test products were comparable to the nonirritant controls. In the 4-day study with both normal and compromised skin sites, test products produced mean erythema scores similar to the nonirritant controls. Three HRIPT separate studies confirm that the products do not induce contact sensitization, including one study conducted on individuals with self-assessed sensitive skin. In the BTK, test and control products produced similar irritation, as assessed by erythema, TEWL and sensory effects.

Conclusion: The results from the patch tests and mechanical irritation test demonstrate good skin compatibility of the new line of products with the unique ONT. In addition, the forms of the product (i.e. liner, pad or brief), were equally compatible with skin.     

Effective topical delivery systems for corticosteroids: dermatological and histological evaluations

Abstract

Atopic dermatitis (AD) is a chronic and relapsing skin disease with severe eczematous lesions. Long-term topical corticosteroid treatment can induce skin atrophy, hypopigmentation and transepidermal water loss (TEWL) increase. A new treatment approach was needed to reduce the risk by dermal targeting. For this purpose, Betamethasone valerate (BMV)/Diflucortolone valerate (DFV)-loaded liposomes (220–350?nm) were prepared and incorporated into chitosan gel to obtain adequate viscosity (～13?000 cps). Drugs were localized in stratum corneum?+?epidermis of rat skin in ex-vivo permeation studies. The toxicity was assessed on human fibroblast cells. In point of in-vivo studies, pharmacodynamic responses, treatment efficacy and skin irritation were evaluated and compared with previously prepared nanoparticles. Liposome/nanoparticle in gel formulations produced higher paw edema inhibition in rats with respect to the commercial cream. Similar skin blanching effect with commercial creams was obtained via liposome in gels although they contain 10 times less drug. Dermatological scoring results, prognostic histological parameters and suppression of mast cell numbers showed higher treatment efficiency of liposome/nanoparticle in gel formulations in AD-induced rats. TEWL and erythema measurements confirmed these results. Overview of obtained results showed that liposomes might be an effective and safe carrier for corticosteroids in skin disease treatment.     

Investigation of different emulsion systems for dermal delivery of nicotinamide

Nicotinamide (NA) has been shown to have beneficial effects on several skin diseases such as tumor, acne vulgaris, photodamage, cellulite and atopic dermatitis. The purpose of this study was to develop a multiple emulsion and a microemulsion formulation as delivery systems for NA. A two-step process was used to prepare the W/O/W multiple emulsion. Optimum microemulsion formulation was selected by using construction of pseudo-ternary phase diagram. The physicochemical properties such as droplet size and viscosity measurements, stability studies were also evaluated. Ex-vivo permeation studies were performed with Franz-type diffusion cells and the samples were analysed by high performance liquid chromatography (HPLC). The permeation data showed that there was no significant difference between multiple emulsion and microemulsion (p > 0.05). Transepidermal water loss (TEWL) was also measured. As a result of TEWL studies, a slight increase of TEWL values was observed for microemulsion formulation on rat skin when compared with multiple emulsion and commercial formulation. The results suggested that microemulsion and multiple emulsion formulations could be new and alternative dosage forms for topical application of NA.     

Solid lipid nanoparticles-loaded topical gel containing combination drugs: an approach to offset psoriasis

Aim: The primary aim of present work was to develop effective combination drug therapy for topical treatment of psoriasis.

Methods: Betamethasone dipropionate and calcipotriol loaded solid lipid nanoparticles (CT-BD-SLNs) were prepared by hot melt high shear homogenization technique, which were then incorporated in Carbopol gel matrix. The anti-psoriatic potential was tested by sequential in vitro (skin permeation and dermal distribution, anti-proliferative effect in HaCaT cells) and in vivo (Draize patch irritation, transepidermal water loss (TEWL) and anti-psoriatic mouse tail studies) experiments.

Results: A negligible amount in receptor compartment, yet confined distribution of drugs to epidermal and dermal region of skin was observed in case of SLNs, which is essential for safe and effective anti-psoriatic therapy. Draize patch test and TEWL demonstrated negligible skin irritation and better skin tolerability of SLNs. The in vitro HaCaT cell line study demonstrated that SLNs delayed the abrupt growth of keratinocytes, while in vivo mouse tail model showed that SLNs gel significantly decreased the epidermal thickness and increased melanocyte count in comparison to commercial Daivobet® ointment.

Conclusions: The developed SLNs gel is expected to be potential strategies for treatment of psoriasis and other topical diseases.     

Dermal safety assessment of Arm & Hammer laundry products formulated for sensitive skin

Context: The prevalence of sensitive skin among the general population in industrialized countries is reported to be over 50%. Sensitive skin subjects often report significant reactions to contact with cosmetics, soaps and other consumer products.

Objective: This paper describes the overall skin compatibility and mildness program for a newly developed, lightly fragranced, colorant free laundry product (i.e. Arm &; Hammer? Sensitive Skin plus Skin-Friendly Fresh Scent), specially formulated for individuals with sensitive skin. The skin mildness of the product was compared to Arm &; Hammer? Free &; Clear liquid laundry detergent with no fragrance or colorant, and an established history of safe use by sensitive skin consumers.

Materials and methods: The test material was a liquid laundry product with a light scent formulated for sensitive skin consumers (Arm &; Hammer? Sensitive Skin plus Skin-Friendly Fresh Scent). The product was compared to commercially marketed products for sensitive skin with a history of skin safety in the marketplace, including: a very similar product formulation (Arm &; Hammer? Free &; Clear with no fragrance), and several selected competitors’ products. Studies were conducted among individuals with self-assessed sensitive skin (based on a questionnaire) using standard protocols for the Human Repeat Insult Patch Test (HRIPT), 10-Day Cumulative Irritation, the Wrist Band Wear test, and the Safety In-Use testing. Responses in all protocols were evaluated by visual scoring of potential dermatologic reactions, and recording any sensory effects at the time of the examination. In addition, sensory effects collected from panelists’ daily diaries were also evaluated.

Results: The HRIPT confirmed that neither the fragrance alone, nor the product formulation with fragrance, induced contact sensitization in sensitive skin subjects. The 10-Day cumulative irritation study conducted using sensitive skin subjects showed highly favorable skin compatibility, and the test product was comparable to the control product (Arm &; Hammer Free &; Clear) and other nonirritant controls. In the Wrist Band Wear test, exposure to laundered fabrics under exaggerated conditions gave similar results for the test and control products, with no objective signs of skin irritation, and no self-reported persistent adverse sensory effects. Very mild, transient and isolated sensory effects were noted in daily diaries by a small proportion of subjects, and were similar for the test and control products. The Safety In-Use tests evaluated 4-week exposure to product and laundered fabrics under realistic use conditions. There were no clinically objective signs of skin irritation, and reports of transitory, mild sensory effects were minimal and similar for the test and controls.

Discussion and conclusion: A comprehensive skin safety program on a lightly scented sensitive skin laundry formulation (i.e. Arm &; Hammer? Sensitive Skin plus Skin-Friendly Fresh Scent) conducted among panels of self-assessed sensitive skin subjects demonstrated that the presence of a light fragrance did not adversely impact skin compatibility in any of the testing protocols when the product was compared to a similar product with no fragrance. The lightly fragranced product demonstrated overall skin compatibility and mildness when tested in a self-assessed sensitive skin population, and compared favorably to currently marketed sensitive skin products.     

Photostability and efficacy studies of topical formulations containing UV-filters combination and vitamins A, C and E

It is already known that the photostability of a sunscreen is important for its performance on human skin. On the other hand, there are many formulations besides sunscreens containing combinations of UV-filters and daily use active substances with other claims like hydration and anti-aging effects. Vitamins A, C and E are frequently added in these kinds of products and it is not known if the UV-filters have some influence on the hydration and anti-aging effects of these vitamins on the skin as well as on their stability mainly when photounstable UV-filters like avobenzone and octyl methoxycinnamate are present in the formulation. Thus, the aim of this study was to evaluate the influence of two different UV-filters combinations, a photostable and a photounstable one, on the photostability as well as on the efficacy of a formulation containing vitamin A, C and E derivatives. The formulations that were investigated contained or not (vehicle: formulation 1) a combination of 0.6 % (w/w) vitamin A palmitate (1,700,000 UI/g), 2 % (w/w) vitamin E acetate and 2% (w/w) ascorbyl tetraisopalmitate (formulation 2) supplemented with a photounstable UV filter combination octyl methoxycinnamate (OMC), avobenzone (AVB) and 4-methylbenzilidene camphor (MBC) (formulation 3) or with a photostable UV filter combination OMC, benzophenone-3 (BP-3) and octocrylene (OC) (formulation 4). In the photostability studies, all formulations were spread onto a glass plate and exposed to UVA/UVB irradiation. The filter components and vitamins were quantified by HPLC analysis with detection at 325 and 235 nm and by spectrophotometry. To simulate the effects of these formulations daily use, all of them (formulations 1-4) were applied on the dorsum of hairless mice, which were submitted to a controlled light-dark cycle (and were not irradiated), once a day for 5 days. Transepidermal water loss (TEWL), water content of the stratum corneum and viscoelastic properties of the skin were analyzed by using different non-invasive Biophysics Techniques in order to evaluate hydration and anti-aging effects of these formulations as well as erythema to assess skin irritation. Histopathology, viable epidermal thickness as well as the number of epidermal cell layers were also evaluated. It was observed that both UV filters combinations (photounstable one containing OMC, AVB and MBC and photostable one containing OMC, BP-3 and OC) enhanced vitamin A photostability and F4 was more photostable than F3, in terms of vitamin A. In vivo efficacy studies showed that F2, F3 and F4 enhanced the viable epidermal thickness, the number of epidermal cell layers, TEWL and Uv/Ue parameter, when compared to the vehicle, which can suggest that they enhanced viable epidermis hydration and acted in cell renewal. However formulation 2 (containing only vitamins), which was the most photounstable formulation, provoked an irritation on hairless mouse skin, and consequently it cannot be considered as safe as the other formulations. It can be concluded that both UV filters combinations did not influence the hydration and anti-aging effects of the formulations containing the vitamins under study and reduced the skin irritation observed when the vitamins were present in the formulation. In addition, the photostable UV-filters combination had the highest recovery of vitamin A in the photostability studies. Finally, it could be suggested that the presence of UV-filters can be considered interesting for the reduction of skin irritation and the most suitable formulation was the one containing the combinations of vitamins A, C and E with photostable UV-filters.     

COMPARISON OF THE RESPONSE TO TOPICAL IRRITANTS IN HAIRLESS GUINEA PIGS AND HUMAN VOLUNTEERS

ABSTRACT

Small rodent laboratory animals lack the complex cutaneous structure and function of human skin, resulting in “all or none” responses to mild irritants so that the animals may show a less discriminative reaction pattern compared to human volunteers (HV). However, histological studies suggest that the skin of the hairless guinea pig (HLGP) is more similar to human skin than to the skin of haired guinea pigs and other rodents. We compared the tolerance pattern of six composite topical formulations with weak irritant potential in 20 human volunteers (HV) and in 15 male HLGPs. The skin care formulations (SCF), with and without either isopropyl palmitate, glycerol, canola oil, or (-)-α-bisabolol, were selected because they were known to cause a differentiated irritative response in HLGP. The HLGPs were treated twice a day on a 5 × 5 cm area on each flank with a SCF for four consecutive days. The irritant effects were quantified by clinical assessment, measurement of transepidermal water loss (TEWL), and colorimetry (a*-parameter). In humans the tolerability was evaluated clinically using the chamber scarification test. The ranking of the formulations was similar in the two models. However, HLGPs were statistically more sensitive to the formulations. Negative results in HLGPs are predictive of good tolerability in humans; however, positive results in the HLGPs do not necessarily indicate that a topical formulation cannot be used in humans.     

Nanoemulsions as potential vehicles for transdermal and dermal delivery of hydrophobic compounds: an overview

Introduction: In recent years, nanoemulsions have been investigated as potential drug delivery vehicles for transdermal and dermal delivery of many compounds especially hydrophobic compounds in order to avoid clinical adverse effects associated with oral delivery of the same compounds. Droplet size and surface properties of nanoemulsions play an important role in the biological behavior of the formulation.

Areas covered: In this review, current literature of transdermal and dermal delivery of hydrophobic compounds both in vitro as well as in vivo has been summarized and analyzed.

Expert opinion: Nanoemulsions have been formulated using a variety of pharmaceutically acceptable excipients. In many cases of dermal and transdermal nanoemulsions, the skin irritation or skin toxicity issues on human beings have not been considered which needs to be evaluated properly. In the last decade, much attention has been made in exploring new types of nanoemulsion-based drug delivery system for dermal and transdermal delivery of many hydrophobic compounds. This area of research would be very advantageous for formulation scientists in order to develop some nanoemulsion-based formulations for their commercial exploitation and clinical applications.     

Comparison of PLGA and lecithin/chitosan nanoparticles for dermal targeting of betamethasone valerate

Abstract

Poly(lactide-co-glycolide) (PLGA) and lecithin/chitosan (LC) nanoparticles were prepared to evaluate the difference in the behavior upon administration on skin, for steroidal treatment. For this purpose, betamethasone-17-valerate (BMV)-loaded nanoparticles with a narrow size distribution and high entrapment efficiency were prepared. Permeation studies showed that both polymeric nanoparticles enhanced the amount of BMV in epidermis, which is the target site of topical steroidal treatment, when compared with commercial formulation. 1.58-Fold increase was determined in the epidermis concentration of BMV by LC nanoparticles with respect to PLGA nanoparticles. Nanoparticles were diluted in chitosan gel (10%, w/w) to prepare suitable formulation for topical application. Accumulation from both gel formulations were found significantly higher than commercial formulation in skin layers (p?<?0.05). In addition, pharmacodynamic responses were also investigated as anti-inflammatory and skin-blanching parameters. Both formulations significantly improved these parameters although they contained 10 times less amount of BMV than commercial cream. Moreover, TEWL measurement exhibited no barrier function changes upon the application of nanoparticles on skin. Overall, both nanoparticles improved the localization of BMV within skin layers; but when compared with PLGA nanoparticles, the LC nanoparticles could be classified as a better candidate for topical delivery vehicle in the treatment of various dermatological inflammatory diseases.     

Skin Irritation in Transdermal Drug Delivery Systems: A Strategy for its Reduction

Purpose Active pharmaceutical ingredients (API) in transdermal drug delivery systems (TDS) often causes skin irritation such as erythema and edema. We have studied a possible approach for the reduction of skin irritation by patch formulations that control the rates of skin permeation and elimination of API. Methods Loxoprofen (LX-base) was used to induce the skin irritation. The redness value (Δa) was evaluated as a measure of erythema by Chroma Meter. The in vitro skin permeation and release profiles were also investigated by using a side-by-side diffusion cell. Results The redness values were not correlated either with the cumulative amount of API permeated or the concentration of LX-base in the skin, but well correlated with the elimination rate of LX-base from the skin after the removal of the formulation. The formulation with gradual decrease of permeation rate during application accelerated the elimination rate after application, and resulted in the reduction of the skin irritation. Conclusions The skin pharmacokinetics of API, not only permeation during application but also release after the patch removal, was found to be a significant factor for skin irritation. To minimize the skin irritation, it’s also important to eliminate the residual API in the skin promptly after application.     

Microsponges enriched gel for enhanced topical delivery of 5-fluorouracil

Abstract

This study aimed to develop microsponges based topical gel formulation of 5-Fluorouracil (5-FU) for the treatment of skin cancer with enhanced skin deposition and reduced skin irritation potential. Microsponges were prepared by Quasi-emulsion solvent diffusion method using ethyl cellulose and Eudragit RL 30?D; and was optimised through detailed in vitro characterisation. Brunauer–Emmett–Teller (BET) analysis demonstrated higher surface area (2.4393?m²/g) and pore volume of developed microsponges formulation. Optimised formulation showed better thixotropic and texture properties compared to commercial cream formulation, used as control for comparison purpose. Further, the optimised formulation demonstrated 5.5-fold increase in skin deposition documented via in-vivo local bioavailability study, with significant reduction in skin irritation compared to the commercial formulation. Hence, the developed microsponges based formulation seems to be a viable alternative with enhanced topical delivery of 5-FU as compared to the commercial formulation.     

Percutaneous absorption of capsaicin,nonivamide and sodium nonivamide acetate from gel and ointment bases: In vitro formulation evaluations in pigs and in vivo bioengineering methods in humans

Nonivamide (NVA) and non-pungent sodium nonivamide acetate (SNA) are synthetic derivatives of capsaicin. In this study, in vitro formulation evaluations in pigs and in vivo bioengineering methods in humans were performed to obtain the information on percutaneous absorption for capsaicin, NVA and SNA. After the consideration of penetration capacity, skin irritation and physicochemical properties of the formulations in vitro, 0.6% Carbopol 940® gel form for capsaicin and NVA as well as 3.8% isopropyl myristate-added hydrophilic o/w ointment for SNA were utilized to study the following in vivo test in humans. In the study of in vivo surface recovery techniques, SNA showed an equivalent therapeutic capability to that of NVA after calculation of the antinociceptive index. After the quantification of skin erythema by laser Doppler flowmetry (LDF), capsaicin caused more severe irritation than NVA in humans. In addition, SNA showed no skin irritation, toxicity and pungent sensation. The transepidermal water loss (TEWL) values were determined using an evaporimeter. A comparison of the gel form showed there was significantly higher TEWL AUC values in capsaicin and NVA than in the control group. The AUC value of the hydrophilic ointment control group was significantly higher than that of the gel control group. The reason was that isopropyl myristate and sodium laurylsulfate, two additives incorporated in the hydrophilic base, could cause slight skin irritation resulting in the increase of TEWL. The results of this study suggest that SNA possesses potent antinociceptive activities after transdermal application. Furthermore, SNA can be used extensively in clinical therapy because it avoids any pungent skin sensation and burning pain to improve patients' compliance.     

Designing a tool allowing for a standardized assessment of resistance to drug diversion

Objectives: Drug diversion is a growing problem in numerous countries. Some laboratories have developed tamper-resistant formulations. The problem for healthcare authorities is now to assess new formulations developed to limit the risk of diversion for administration by another mode and intended mode. It would be helpful to have a pertinent panel of in vitro tests allowing assessment of how a formulation may be altered, both for healthcare authorities and for laboratories, so as to implement adequate sanitary measures. We designed a methodology/tool allowing assessment, in a standardized manner, of the formulation's resistance to drug diversion. We present the various steps leading to the construction of the scale and to its first use.

Methods: Creating a Steering Committee – Choosing assays or parameters – standardized by a monograph of the European Pharmacopoeia and pragmatic assays related to users' behaviors – for the assessment of formulation resistance to drug diversion. Designing a scale: i) applying all these tests to a panel of formulations; ii) applying a score by drug and by test; and iii) attribution of weighting per test and calculating the total score for a drug.

Results: Eight tests or parameters and 14 drugs (diverted drugs and controls) were chosen. Buprenorphine Subutex® had the lowest score and flunitrazepam Rohypnol® the highest.

Conclusions: Our tool allowed classification of the various drugs selected. This classification correlated with results of postmarketing authorization assessment. Rohypnol®, which was the object of many measures, including formulation changes, obtained the highest score in our study.     

CPT,the main test method of skin neuronal sensitivity

Background: Many scholars concentrate on skin barrier disruption of sensitive skin, but few focus on its increased neuronal sensitivity.

Objective: To study the possibility of using current perception threshold (CPT) measurement for the quantitative evaluation of skin neuronal sensitivity combined with stinging test.

Methods: The amount of 50?μL 10% lactic acid was applied on each side of the nasolabial fold at random. Subjects assessed stinging based on a 4-point scale at 30?s, 2.5?min and 5.0?min. CPT and transepidermal water loss (TEWL) were measured before and after stinging test. Subjects were divided into different groups based on their response to lactic acid.

Results: There was a positive correlation between CPT_before and the sum of clinical scores (CSs). While the beginning time of stinging (BT) was shortened, the CPT_before decreased and TEWL increased.

Conclusion: Different degrees of skin susceptibility can be reflected by BT. CPT can be useful for the quantitative evaluation of skin neuronal sensitivity.     

Impacts of chemical enhancers on skin permeation and deposition of terbinafine

Abstract

Context/Objective: The addition of chemical enhancers into formulations is the most commonly employed approach to overcome the skin barrier. The objective of this work was to evaluate the effect of vehicle and chemical enhancers on the skin permeation and accumulation of terbinafine, an allylamine antifungal drug.

Methods: Terbinafine (1% w/w) was formulated as a Carbopol 934?P gel formulation in presence and absence of three chemical enhancers, nerolidol, dl-limonene and urea. Terbinafine distribution and deposition in stratum corneum (SC) and skin following 8-h ex vivo permeation study was determined using a sequential tape stripping procedure. The conformational order of SC lipids was investigated by ATR-FTIR spectroscopy.

Results and discussion: Nerolidol containing gel formulation produced significantly higher enhancement in terbinafine permeation through skin and its skin accumulation was increased. ATR-FTIR results showed enhancer induced lipid bilayer disruption in SC. Urea resulted in enhanced permeation of terbinafine across the skin and a balanced distribution to the SC was achieved. But, dl-limonene could not minimize the accumulation of terbinafine in the upper SC.

Conclusion: Nerolidol dramatically improved the skin permeation and deposition of terbinafine in the skin that might help to optimize targeting of the drug to the epidermal sites as required for both of superficial and deep cutaneous fungal infections.     

Formulation and Characterization of Benzoyl Peroxide Gellified Emulsions

The present investigation was carried out with the objective of formulating a gellified emulsion of benzoyl peroxide, an anti-acne agent. The formulations were prepared using four different vegetable oils, viz. almond oil, jojoba oil, sesame oil, and wheat germ oil, owing to their emollient properties. The idea was to overcome the skin irritation and dryness caused by benzoyl peroxide, making the formulation more tolerable. The gellified emulsions were characterized for their homogeneity, rheology, spreadability, drug content, and stability. In vitro permeation studies were performed to check the drug permeation through rat skin. The formulations were evaluated for their antimicrobial activity, as well as their acute skin irritation potential. The results were compared with those obtained for the marketed formulation. Later, the histopathological examination of the skin treated with various formulations was carried out. Formulation F3 was found to have caused a very mild dysplastic change to the epidermis. On the other hand, the marketed formulation led to the greatest dysplastic change. Hence, it was concluded that formulation F3, containing sesame oil (6%w/w), was the optimized formulation. It exhibited the maximum drug release and anti-microbial activity, in addition to the least skin irritation potential.     

Texturing formulations for uranium skin decontamination

Abstract

Context: Since no specific treatment exists in case of cutaneous contamination by radionuclides such as uranium, a nanoemulsion comprising calixarene molecules, known for their good chelation properties, was previously designed. However, this fluid topical form may be not suitable for optimal application on the skin or wounds.

Objective: To develop a texturing pharmaceutical form for the treatment of wounded skins contaminated by uranium.

Materials and methods: The formulations consisted in oil-in-water (O/W) nanoemulsions, loaded with calixarene molecules. The external phase of the initial liquid nanoemulsion was modified with a combination of thermosensitive gelifying polymers: Poloxamer and HydroxyPropylMethylcellulose (HPMC) or methylcellulose (MC). These new formulations were characterized then tested by ex vivo experiments on Franz cells to prevent uranyl ions diffusion through excoriated pig ear skin explants.

Results: Despite strong changes in rheological properties, the physico-chemical characteristics of the new nanoemulsions, such as the size and the zeta potential as well as macroscopic aspect were preserved. In addition, on wounded skin, diffusion of uranyl ions, measured by ICP-MS, was limited to less than 5% for both HPMC and MC nanoemulsions.

Conclusions: These results demonstrated that a hybrid formulation of nanoemulsion in hydrogel is efficient to treat uranium skin contamination.     

Anti-aging efficacy of topical formulations containing niosomes entrapped with rice bran bioactive compounds

Context: Rice [Oryza sativa L. (Gramineae)] bran is a rich source of phytochemicals. Its oil also contains several bioactive components that exhibit antioxidative properties such as ferulic acid (F), γ-oryzanol (O), and phytic acid (P) which can be a new source of cosmetic raw materials.

Objective: To evaluate the anti-aging effects of the gel and cream containing niosomes entrapped with the rice bran bioactive compounds.

Materials and methods: The semi-purified rice bran extracts containing F, O, and P which indicated the growth stimulation of human fibroblasts and the inhibition of MMP-2 by sulforhodamine B and gelatin zymography, respectively, were entrapped in niosomes by supercritical carbon dioxide fluid (scCO₂) and incorporated in gel and cream formulations. The skin hydration, elasticity, thickness and roughness, and pigmentation in human volunteers after treated with these gel and creams were investigated by corneometer, cutometer, visiometer, and mexameter, respectively.

Results: Gel and cream containing the semi-purified rice bran extracts entrapped in niosomes gave no sign of erythema and edema detected within 72?h on the shaved rabbit skin by the closed patch test investigated by mexameter and visual observation, respectively. These formulations also demonstrated higher hydration enhancement and improvement of skin lightening, thickness, roughness, and elasticity on the skin of 30 human volunteers within the 28–day treatment not more than 9, 27, 7, 3, and 3 times, respectively.

Discussion and conclusions: The formulations containing niosomes entrapped with the rice bran bioactive compounds gave superior clinical anti-aging activity which can be applied as a novel skin product.     

Tier-based skin irritation testing of hair cleansing conditioners and their constituents

Purpose/Aim: The U.S. Food and Drug Administration (FDA) does not require specific testing to demonstrate the safety of personal care and cosmetic products or their ingredients. Recently, there have been reports of skin irritation associated with the use of commercially available cleansing conditioners. The goal of this study was to implement a tier-based safety assessment to evaluate the skin irritation potential of six commercially available cleansing conditioners and their ingredients.

Materials and Methods: The first tier of testing utilized the Organization for Economic Co-operation and Development (OECD) QSAR Toolbox to perform an in silico evaluation of the skin irritation potential of the product ingredients, and the second tier of testing utilized an OECD in vitro guideline test to evaluate the skin irritation potential of each product.

Results: Thirty-two ingredients were evaluated using the OECD QSAR Toolbox profiler for the tier one analysis; nine ingredients received a structural alert for skin irritation/corrosion. In the tier two in vitro analysis, the evaluated cleansing conditioner products were all classified as non-irritants.

Conclusions: These results provide evidence that use of the evaluated commercially available cleansing conditioners would not be expected to cause skin irritation among consumers. Additionally, this study demonstrates that the presence of structural alerts does not always accurately predict the safety of a product, as focused tier-based testing is necessary to comprehensively evaluate a product. This study illustrates a tier-based safety assessment approach, applicable to a wide variety of health endpoints, which efficiently and adequately evaluates the safety of personal care and cosmetic products and their ingredients.