Skin permeation of two different benzophenone derivatives from various vehicles

Synopsis The aim of this study was to determine the effects of the vehicles on the release and permeation of the UV filters. Therefore, the release and permeation of lipophilic oxybenzone and hydrophilic sulisobenzone were investigated from four different vehicles; petrolatum, o/w and w/o emulsions and hydroxyethyl cellulose (HEC) gel. Both release and permeation studies were performed by using glass diffusion cells. The vehicle in which oxybenzone has the highest released amount was petrolatum, whereas the highest released amount for sulisobenzone was obtained in HEC gel. The difference between the released amounts of oxybenzone in the other three vehicles was not significant but the released amount of sulisobenzone was least in petrolatum, whereas no significant difference was seen between o/w and w/o emulsions. The results of skin permeation experiments were similar those from release experiments. The order of permeated amounts from highest to lowest was petrolatum, o/w emulsion and HEC gel for oxybenzone, and HEC gel, o/w emulsion and petrolatum for sulisobenzone. These results demonstrate that permeation of the UV filters can be optimized by a suitable vehicle. As the percutaneous absorption of sunscreens should be avoided, the vehicle suggested for oxybenzone and sulisobenzone is o/w emulsion because of its permeation properties and cosmetic acceptance.     

In vitro skin permeation of sunscreen agents from O/W emulsions

The effects of different emulsifiers on the in vitro permeation through human skin of two sunscreen agents [octylmethoxycinnamate (OMC) and butylmethoxydibenzoylmethane (BMBM)] were investigated from O/W emulsions. The test formulations were prepared using the same oil and aqueous phase ingredients and the following emulsifier and coemulsifier systems: Emulgade SE((R)) (ceteareth-12 and ceteareth-20 and cetearyl alcohol and cetyl palmitate) and glycerylmonostearate (emulsion 1); Brij 72((R)) (steareth-2), Brij 721((R)) (steareth-21) and cetearyl alcohol (emulsion 2); Phytocream((R)) (potassium palmitoyl-hydrolysed wheat protein and glyceryl stearate and cetearyl alcohol) and glycerylmonostearate (emulsion 3); Montanov 68((R)) (cetearyl glucoside and cetearyl alcohol) (emulsion 4); Xalifin-15((R)) (C(15-20) acid PEG-8 ester) and cetearyl alcohol (emulsion 5). The cumulative amount of OMC that permeated in vitro through human skin after 22 h from the formulations being tested decreased in the order 3 > 1 congruent with 4 > 5 > 2 and was about nine-fold higher from emulsion 3 compared with that from emulsion 2. As regards BMBM, no significant difference was observed as regards its skin permeation from emulsions 1, 3, 4 and 5, whereas formulation 2 allowed significantly lower amounts of BMBM to permeate the skin. In vitro release experiments of OMC and BMBM from emulsions 1-6 through cellulose acetate membranes showed that only emulsions 4 and 5 provided pseudo-first-order release rates only for OMC. The results of this study suggest that the type of emulsifying systems used to prepare an O/W emulsion may strongly affect sunscreen skin permeation from these formulations. Therefore, the vehicle effects should be carefully considered in the formulation of sunscreen products.     

In vitro skin permeation evaluation: the only realistic option

Increasing requirements for cruelty-free risk assessment in the cosmetic industry have led to the development of several alternative experimental evaluation strategies. Quantification of the potential dermal absorption of ingredients of cosmetic and other formulations by determination of human skin permeation rates in vitro is particularly relevant. Using modifications of standard in vitro protocols the human skin permeation rates of several cosmetic ingredients and potential contaminants have been determined under conditions designed to mimic consumer use. Skin penetration and permeation of octyl salicylate (a sunscreen), nonylphenol ethoxylates (surfactants) and three nitrosamines (potential contaminants) is discussed. The data demonstrate the usefulness of this technique as a tool in the overall risk assessment of cosmetic formulations.     

Substantivity of sunscreens —in vitro evaluation of the transdermal permeation characteristics of some benzophenone derivatives

The in vitro permeation through excised hairless mouse skin of a series of 4-O-(N, N-dimethylaminoalkyl)-benzophenones, non-quaternarized and quaternarized, and of two commercial benzophenone sunscreens, taken as reference compounds, was investigated. The aim of the study was to verify the skin penetration of the highly skin-substantive quaternary ammonium derivatives, in comparison with their parent, non-quaternarized compounds. While the quaternary derivatives proved unable to permeate the skin during the period of observation (45 h), their parent amine hydrochlorides and the reference sunscreens (2-hydroxy-4-methoxy-benzophenone-5-sulphonic acid and 2,2'-dihydroxy-4,4'-dimethoxy-benzophenone 5,5'-sodium disulphonate), showed appreciable transdermal fluxes.
These data indicate that the presence of a quaternary ammonium group in a molecule, besides inducing a high affinity for cutaneous keratin, may result in hindered or reduced transdermal (and possibly systemic) absorption. Both features may contribute in improving the safety of a cosmetic sunscreen.     

Application of TLC and HPTLC in the analysis of semipermanent hair dyes

Semipermanent or direct colouring includes any product capable of affecting to some extent a change in the natural hair colour that will last through at least five shampoo washings. Semipermanent dyes are simple and easy to use, as opposed to oxidation dyes, and are normally formulated for application on nonbleached hair. Following increases in supply of such formulations, we have started an analysis for quality control purposes of 21 commonly marketed dyestuffs (nitroaminobenzenes, anthraquinone and Arianor dyes) and 20 colouring products manufactured by four leading companies. By using TLC (silica gel and reversed phase) and HPTLC (silica gel) procedures we have determined relative retention values to 1,3-diamino-4-nitrobenzene of standards and dyes found in the commercial products. All the values reported (standards and samples) are the average of five analytical results (+/-SD).     

Comparison of percutaneous penetration in vitro using clofibric acid esters and amides as novel enhancers in two species: mouse and guinea pig

A series of clofibric acid esters and amides has been assessed as dermal penetration enhancers towards hydrocortisone-21-acetate, a model drug. In vitro percutaneous absorption experiments on three skin sources (athymic nude mouse, hairless mouse, and hairless guinea pig) showed several compounds to be effective penetration enhancers, the octyl amide providing an approximately 20-fold increase in 24 h diffusion cell receptor drug concentration and 5.7 fold in total steroid skin retention in nude mouse. Azone produced significantly higher (p <0.05) permeation rates than the octyl amide enhancer, but there was a smaller increase in 24 h receptor concentrations, and Azone steroid skin concentrations were significantly less (p < 0.05) than those for the amide. There was no significant difference (p < 0.05) between enhancement in hairless and athymic nude mouse, however, hairless guinea pig skin showed decreased enhancer effectiveness.     

Dyeing behaviours of amino heterocyclic compounds as blue oxidative hair dye precursors applied to keratin fibres

Several novel heterocyclic compounds based on 1,2,3,4-tetrahydroquinoline and 2,3-dihydroindole have been investigated for their application of colour keratin fibres as blue oxidative dye precursors, especially to human hair. The colourants we studied contained anyone of these dyes (concentration range from 0.005% to 6%), and some common oxidative hair dyes, such as p-phenylenediamine, toluene-2,5-diamine sulphate. Experiments were carried out on the method of mixing hair colourants with H(2)O(2) gel at the ratio of 1 : 1, accompanied by pH = 8～11. It is demonstrated that 1,2,3,4-tetrahydroquinoline derivatives could be considered as an excellent candidate for blue dyes, and N-methyl-7-amino-1,2,3,4-tetrahydroquinoline is the most outstanding one among this kind of compounds. They own significant advantages of colour purity, stability and fastness. On the other hand, 2,3-dihydroindoles show the similar colours but not stable and brilliant enough.     

Application of high-performance liquid chromatography in the analysis of direct dyes in semipermanent hair colouring cosmetics

A method for the identification and the quantification of direct dyes in semipermanent hair colouring cosmetics by using a reversed phase high-performance liquid chromatography (HPLC) with gradient elution and diode array detector (DAD) detection is presented. A standard mixture of 18 commonly marketed dyestuffs (11 nitroderivatives, two anthraquinones and five Arianor dyes) was studied. The major problems in the analysis of the mixture of direct dyes is the different chemical structure and especially the wide range of polarities. However we succeeded in the complete separation of the standard dyes. A qualitative analysis of eight colouring commercial products selected from different shades and a quantitative analysis of three of them was carried out. Materials, methods and results are reported.     

Evaluation of a gas in vitro system for predicting methane production in vivo

Methane production from ruminant livestock varies with the diet as a result of factors such as dry matter intake, diet composition, and digestibility. To estimate the effect of dietary composition and feed additives, CH₄ production can be measured in vitro as a first step because large numbers of samples can be incubated and analyzed at the same time. This study evaluated a recently developed in vitro method for prediction of in vivo CH₄ production by examining the relationship between predicted and observed CH₄ production values. A total of 49 different diets (observations), used in previous 13 in vivo studies, were selected to include diets varying in nutrient composition. Methane production was measured in all in vivo studies by respiration chambers or the GreenFeed system (C-Lock Inc., Rapid City, SD). Overall, the in vitro system predicted CH₄ production well (R² = 0.96), but the values obtained were slightly underestimated compared with observed in vivo values (mean 399 L/d compared with 418 L/d: root mean square prediction error = 51.6 L/d or 12.3% of observed mean). Further analysis of the effect on residuals showed no significant relationship between CH₄ production and most factors known to affect CH₄ production such as dry matter intake, digestibility, and dietary concentrations of fat and starch. However, some factors included in the model were not well predicted by the system, with residuals negatively related to neutral detergent fiber concentration and positively related to concentrate proportion. The in vitro system can thus be useful for screening diets and evaluation of feed additives as a first step that can be best interpreted when feeding cows at maintenance level.     

Determination of sun protection factors. Correlation between in vivo human studies and an in vitro skin cast method

Sun protection factors were determined by both an in vitro method which used resin casts taken from replicas of human skin and by an in vivo SPF method. Thirty-eight product development samples were tested for the level of sun protection using both methods and the results were compared. The values obtained showed a positive relationship which was closely approximated by a log-linear regression of in vivo data on in vitro data (regression coefficient, r² = 0.86).
It is concluded that the cast technique is quick, convenient, inexpensive and in its present form useful for screening sunscreen products prior to in vivo SPF testing.     

Determination of impurities in oxidation hair dyes as raw materials by liquid chromatography (HPLC)

Oxidation hair dyes as raw materials may present toxic impurities from synthesis or degradation pathways, which are responsible for allergic phenomena. In the present study selective and sensitive HPLC methods are proposed for the determination of Bandrowski base, 4-chloroaniline, 1,2-phenylenediamine and 4,4'-diaminoazobenzene in 1,4-phenylenediamine as well as 2,4-diaminoanisole in N-hydroxyethyl-4-methoxy-1,3-phenylenediamine. The proposed methods, based on reversed phase mode separation using 1,8-diaminooctane as amine modifier and photodiode array detection, proved to be suitable for the purity assessment of these widely used hair dyes; in particular the cited potential impurities were determined at ppm level.     

Protective effects of taurine on human hair follicle grown in vitro

Taurine is a naturally occurring beta-amino acid produced by methionine and cysteine metabolism. It is involved in a variety of physiological functions, including immunomodulatory and antifibrotic. Taking advantage of the ability of human hair follicle grown in vitro to recapitulate most of the characteristic features of normal hair follicle in vivo, we studied (i) taurine uptake by isolated human hair follicles; (ii) its effects on hair growth and survival rate; and (iii) its protective potential against transforming growth factor (TGF)-beta1, an inhibitor of in vitro hair growth and a master switch of fibrotic program. We showed that taurine was taken up by the connective tissue sheath, proximal outer root sheath and hair bulb, promoted hair survival in vitro and prevented TGF-beta1-induced deleterious effects on hair follicle.     

Synthesis of 2-N-oleoylamino-octadecane-1,3-diol: a new ceramide highly effective for the treatment of skin and hair

2-N-Oleoylamino-octadecane-1,3-diol is a new synthetic ceramide. The process enables a four-step preparation of 2-amino-octadecane-1,3-diol (D,L-erythro/threo) and a five-step synthesis of 2-N-oleoylamino-octadecane-1,3-diol (D,L-erythro/threo). The latter compound is related to ceramide 2 according to the classification of Downing. This route of synthesis is rapid, reproducible and uses low-cost starting materials. The new ceramide was analysed as follows: ¹H, ¹³C, ¹⁵N NMR spectra afforded an unambiguous characterization of the structure; additionally, these three methods identified the threo and erythro isomers. ¹H and ¹³C NMR permitted the measurement of the threo/erythro ratio (26.6/73.4 and 25.5/74.5, respectively). Chemical ionization mass spectrometry confirmed the expected mass of the pseudo-molecular ion (m/z= 566.5: [M + H]⁺) as well as the presence of different chain lengths other than the oleic moiety due to the fatty acid composition of the technical grade oleic acid used for the synthesis. Capillary gas chromatography measured the threo/erythro ratio (23.5/76.5) which agrees with the ¹H and ¹³C NMR data. Moreover, this method afforded the relative distribution of the different N-acylated chains. The properties of the new synthetic ceramide for the treatment of skin and hair were mainly assessed by two in vitro methods. The first measured the flux of water through lipid-extracted stratum corneum. The described ceramide showed high efficacy in decreasing water loss. The second recorded the friction coefficient of different types of hair: virgin, permanent-waved, and bleached. Treatment by the ceramide led to a strong decrease in this coefficient. This was particularly observed on unrinsed hair. These findings suggest two potential fields of application and beneficial contribution for the new ceramide: repairing the barrier to transepidermal water loss, and improving the surface properties of hair. Synthèse du 2-N-oleoylamino-octadécane-1,3-diol: nouveau céramide à haut potentiel dans le soin de la peau et du cheveu.     

Development of an in vitro efficacy test for self-tanning formulations

In the last few years, the desire to acquire a tan without sunbathing has grown. In response, many cosmetic companies have produced self-tanning preparations. However, to optimize these formulations, a suitable model to assess the colour induced on the skin remains to be developed. We have developed an in vitro method using a synthetic skin in order to study the efficacy of self-tanning formulations. The in vitro test was then used to study the influence of cosmetic ingredients upon the colour induced by erythrulose- or dihydroxyacetone-containing formulations. Finally, an in vivo study allowed us to relate the results obtained in vitro with those found on human skin. The results show that this in vitro test system is a reliable tool to predict the efficacy of self-tanning products.     

A comparison of biological activities of a new soya biopeptide studied in an in vitro skin equivalent model and human volunteers

During aging, the epidermis and dermis become thin and an efficient anti-aging product should be able to stimulate the metabolism of senescent fibroblast and keratinocytes, in order to increase the quantity of extra-cellular matrix components such as collagen and glycosaminoglycans. A study performed in parallel on an in vitro skin equivalent model, and in vivo, with human volunteers, demonstrated the efficacy of one specific soya biopeptide for anti-aging properties. Such a biopeptide induces a significant increase of glycosaminoglycans synthesis in vitro and in vivo after a one-month treatment. We also showed that this new cosmetic ingredient is able to stimulate favourably the collagen synthesis in vitro and in vivo. This study provided the proof for anti-aging properties of a new soya biopeptide and also validated the skin equivalent model developed for this experimentation as an alternative method to animal or human testing for some cosmetic efficacy evaluations.     

凝胶渗透色谱-高效液相色谱法测定糟蛋中4种 苏丹红的残留量

目的建立一种凝胶渗透色谱-高效液相色谱法(gel permeation chromatography-high performance liquid chromatography,GPC-HPLC)同时测定糟蛋中4种苏丹红(苏丹红Ⅰ、Ⅱ、Ⅲ和Ⅳ)的方法。方法糟蛋样品经环己烷-乙酸乙酯提取,经Bio-Beads S-X3凝胶柱净化;采用Agilent Zorbax SB C_(18)色谱柱对糟蛋中4种苏丹红进行分离,以97%乙腈水溶液为流动相,流速为1.0 m L/min,用配有紫外检测器的液相色谱仪检测,检测波长为478 nm和520 nm。结果 4种苏丹红样品在0.1~25.0 mg/L浓度范围内线性良好(r~20.999),该方法的检测限为6.3~11.9μg/kg,加标回收率为86.0%~101.2%,相对标准偏差(RSD)在1.68%~4.58%之间。结论本方法操作简便、准确可靠,可应用于糟蛋中苏丹红的检测。     

红平菇胞外多糖体外抗氧化及对高血脂小鼠体内抗氧化能力探究

目的:探究红平菇胞外多糖(Extracellular polysaccharides,EPS)体外抗氧化能力及抵抗高血脂小鼠体内肝脏组织氧化损伤的功效.方法:通过EPS 对0-2·、DPPH 自由基和.OH 的清除力,测定其体外抗氧化能力;构建高血脂小鼠模型,分为空白对照组(NC)、高血脂模型组(MC)、阳性对照组(P...     

The role of chelants in controlling Cu(II)‐induced radical chemistry in oxidative hair colouring products

The catalytic formation of hydroxyl radicals in oxidative hair colourant systems in the presence of added copper ions was measured and quantified using a colorimetric probe N,N′‐(5‐nitro‐1,3‐phenylene)bisglutaramide. Also monitored in the same experiments was the decomposition of hydrogen peroxide. The first set of experiments was performed using aqueous model solutions containing the key oxidant actives in a hair colourant, ammonium hydroxide and hydrogen peroxide at pH 10, with added copper and calcium ions. The second set of experiments was performed in the presence of hair containing different levels of copper in conditions very close to those found during hair colouring. Both sets of experiments demonstrate the ability of copper ions to trigger the formation of hydroxyl radicals and catalyse the decomposition of hydrogen peroxide. The ability of chelants ethylenediamine tetraacetic acid (EDTA) and N,N′‐ethylenediamine disuccinic acid (EDDS) to moderate the flux of hydroxyl radicals formed in solution systems was demonstrated in the presence of copper ions alone. However, only EDDS was successful in the presence of both calcium and copper ions. This was confirmed in the hair experiments where again only EDDS was successful at preventing hydroxyl radical formation where hair is added as the source of copper and calcium ions. These results are explained using metal speciation modelling and demonstrate the importance of the chelant to be able to specifically bind and prevent the one‐electron redox chemistry of copper in the presence of high levels of calcium ions as found in hair. The formation of hydroxyl radicals during the colouring process was shown to lead to hair structure damage as measured by protein loss. EDDS was demonstrated to significantly reduce cuticle damage by suppressing the formation of the hydroxyl radicals in systems with realistic concentrations of calcium and copper.