Showing papers in "Journal of Cosmetic Science in 2000"

Preparation of a new soft capsule for cosmetics

Abstract: A novel microcapsule for cosmetics was studied. The microcapsule was prepared by using an O/W/O emulsification technique and showed high thermostable properties (> 70°C). Agar was employed to gel the water phase of the emulsion. The size of the microcapsules was controlled by the process temperature and the stirring speed: the higher the temperature or the stirring speed, the smaller the diameter of the microcapsule produced. The strength of the agar gel phase was investigated, and the effect of the ratio of the internal oil to the gel (water) phase was observed. Young's modulus decreased with increase of the internal oil ratio. For cosmetic applications of the microcapsules, the all trans-retinol palmitate or ethyl linoleate used as a model ingredient was stabilized by microencapsulation. The remaining percentages of all trans-retinol palmitate and ethyl linoleate in the microcapsule after the four-week experiments at 50°C were 87% and 95%, respectively. On the other hand, those in oil solution were 72% and 91%, respectively. This microcapsule shows suitable properties for not only cosmetic use, but also for applications in foods and other products.

A photographic scale for the assessment of human facial wrinkles

Abstract: We report the utility of photographic scales to assess the degree of human facial wrinkles. A five-grade photo scale of wrinkles at eye corners was developed using photos obtained from 411 female participants aged 17 to 83 years. Based on this photo scale, scorings (five grades and nine grades) of all photos were performed by two specialists, and a standard photo for each wrinkle grade was obtained. In addition, in order to evaluate the influence of inter-observer differences in grading criteria, another scoring was performed by five general observers. The agreement between the grade standard and the score given by the general observers was evaluated by calculating the chance-corrected coefficient, i.e., the kappa value. The degree of agreement for the five-grade scale was more consistent than that for the nine-grade scale system, in which the kappa values were 0.499 and 0.396, respectively. When scoring was performed using the five-grade photo scale for the eye corners after 15 participants used a wrinkle-improving agent, a significant reduction of the wrinkle scores was confirmed. Taken together, the present findings indicate that the five-grade wrinkle photo scale is valid and useful to assess the degree of facial wrinkles.

Oxygen radicals from photoirradiated human hair: An ESR and fluorescence study

Abstract: Exposure of hair to light causes degradation, the precise mechanism of which is not completely understood. Oxygen free radicals (superoxide and hydroxyl) are believed to be involved, and a variety of indirect evidence has supported this. However, to date, direct observation of oxyradicals from photoirradiated hair has been lacking. We have used complementary electron spin resonance and fluorescence techniques to assess oxyradical production when human hair is irradiated under UVA and visible light (λ ≥ 320 nm). ESR studies include direct observation of intrinsic melanin and keratin radicals as well as spin trapping with DMPO. The fluorescence technique is based on terephthalic acid dianion (TA) as a hydroxyl radical probe. Radical scavengers are used to compete with the probe (TA or DMPO). Our results indicate that (a) oxyradicals are produced during photoirradiation, (b) terephthalate is a convenient method to study hydroxyl production in hair, (c) radical production upon irradiation varies with hair type, and (d) the effects of radical scavengers suggest potential implications for hair care product development.

The use of chemical probes to assess the facial reactivity of women, comparing their self-perception of sensitive skin

Abstract: Sensitive skin is a term that has a very distinct meaning to each individual, but over a large group the definition may vary considerably. In this study approximately 1000 Caucasian females (ages 18 to 65) in five geographically diverse locations (Arizona, Ohio, New Jersey, Manitoba, and Florida) were recruited to answer a questionnaire that specifically asked, Do you have sensitive skin? and also documented dermatological parameters and reactions to products. Three chemical probes were applied to each volunteer on separate visits to the laboratory: 10% aqueous lactic acid, 10% balsam of Peru, and 10:90 chloroform/ methanol. Burning/stinging responses were recorded each minute for up to ten minutes. The endpoints for analysis were (a) time in minutes for perceived burning/stinging and (b) maximum score achieved. The study was undertaken to compare individuals who classified themselves on a written questionnaire as having sensitive skin with a group of individuals self-classified as having non-sensitive skin. The response parameters for each of the chemical probes were correlated with the subject's self-assessment of sensitive skin condition, skin medical history, and tendencies for personal care product selection. With each of the chemical probes, a statistically significant difference was found between the responsiveness of the self-assessed sensitive skin and non-sensitive skin groups for the parameters measured (time to perceived burning/stinging and maximum score achieved). However, there were a large number of subjects self-perceived as sensitive who did not respond to any of the chemical probes, while others self-perceived as non-sensitive responded strongly. Analysis of demographic and response data did not identify any specific profile of responders and non-responders. These results indicate that individual perception of sensitive skin by self-assessment may not always conform to the functional determination of sensitivity to chemical probes.

Measurement of hair luster by diffuse reflectance spectrophotometry

Abstract: We studied the application of the diffuse reflectance spectrophotometry technique in order to obtain consistent hair-luster measurements. The influence on data quality of such experimental conditions as sample color, texture, geometry, and position, and of such instrumental operating conditions as viewing angle, viewing aperture, and inclusion or exclusion of the specular component, were established. The color-difference parameter (DE) appears as the best parameter to measure hair luster in CIELAB and FMCII systems of equations. Hair tresses submitted to several treatments, including shampooing and conditioning, were used to choose the best reference (zero-luster value) and hair-luster saturation (maximum-luster value). A luster scale was assembled from DE values, pointing out that diffuse reflectance spectrophotometry data allows measuring and quantifying hair luster.

Development of a modified forearm controlled application test method for evaluating the skin mildness of disposable wipe products

Abstract: A modified forearm controlled application technique (modified FCAT) was developed to evaluate the relative mildness of baby wipe products. The test uses a semi-occlusive patch system to mimic the hydrated conditions common to the skin in the diaper area, interspersed with repeated product applications. The skin condition is scored for four endpoints: visual scoring for erythema and dryness, and instrumental scoring for redness (using a chromameter) and transepidermal water loss (TEWL by evaporimeter). The variables evaluated in the course of developing the method include the optimum patch system to achieve hydration, the specific procedure for applying the test products, and the minimum test duration required to achieve significant differences for all four endpoints. The optimum study design produces statistically significant differences between baby wipe test products in all four endpoints. This method has applicability for wipes intended for other uses where mildness and irritation are critical considerations, such as wipes intended for cosmetic removal.

Characterization of the physical factors affecting nail permeation using water as a probe

Abstract: Synopsis Our research objectives were to (a) develop a reproducible technique to measure nail permeation in vitro, (b) study variations in nail permeability as a function of location (toenails vs fingernails), and (c) study the effect of pH and temperature. We monitored the permeation of tritiated water from aqueous gels using specialized Franz-type diffusion cells. For pH studies, the gels were buffered at pH 2, 7, and 12. For temperature studies, three settings (37oC, 47oC, and 57oC) were investigated. Our results showed that there was a large interindividual variability in nail permeation. Normalization of the data for toenail thickness reduced the standard deviation for flux from 42% to 21% of the mean value. Repeated measurements resulted in less than 5% variability, indicating that the technique was reproducible. Thumbnails, despite their reduced thickness, resulted in water fluxes equal to those of toenails, suggesting the presence of a tighter keratin network. Although not conclusive, our results suggest that thumbnails also differ in structure from other fingernails. While pH did not affect permeation through nails, increased temperature significantly enhanced water permeation. The effects of pH and heat treatment were reversible.

Elution of S100A3 from hair fiber : New model for hair damage emphasizing the loss of S100A3 from cuticle

Abstract: In hair fiber, a cysteine-rich calcium-binding S100A3 protein is segregated in the inner part of the cuticle and postulated to play an important role in the attachment to the adjacent cuticular scale. In this study, elution of S100A3 from hair fiber was examined under various conditions by means of immunoblot analyses. The exposure of hair fiber to permanent waving lotions resulted in recoveries of substantial amounts of S100A3 by elution. Ultraviolet-light radiation and perming also increased the elution of S100A3 even without reductant. The distal part of hair fiber eluted less S100A3, as compared to the proximal section, under reducing conditions. These results suggest that S100A3 is eluted preferentially by daily washing and rinsing, especially from damaged hair. Given the presence of soluble S100A3 in the inner part of cuticle, we propose a new mechanism of hair damage in which the elution of S100A3 plays a major role.

A curing method for permanent hair straightening using thioglycolic and dithiodiglycolic acids

Abstract: A successful process of permanent hair straightening was achieved by applying a hot iron press technique to hair treated with an alkaline solution containing thioglycolic acid (TGA) and dithiodiglycolic acid (DTDG). Supercontraction of the hair was determined on the basis of fiber length. The effectiveness of straightening was evaluated as a function of supercontraction, which was dependent on the concentration ratio of DTDG to TGA, pH, time, and heat-treatment temperature. A range of around 5% to 8% supercontraction was found to be necessary to achieve successful permanent hair straightening, while at relatively higher contraction levels the smoothness of the fiber surface tended to be lost. About 89% of the initial content of cystine was retained in straightened hairs, and about 11% was converted to cysteic acid. X-ray diffraction and high-pressure differential scanning calorimetry were used to estimate the amount of α-crystallites. The relationship between the melting enthalpy and the degree of supercontraction was discussed in relation to the stability in the straight configuration. Important conclusions include the observations that supercontraction of less than 10% is caused by randomization of the α-helix and that permanency related to hair straightening is a result of the irreversible transformation of the α-crystal into amorphous phase.

Film-formation time, skin hydration effects, and physicochemical properties of moisture masks containing different water-soluble chitosans

Abstract: The effect of the addition of water-soluble chitosans on the skin hydration effects and the physicochemical properties of moisture masks thus prepared were studied. Results show that the apparent viscosity of moisture masks increased with increasing molecular weight and/or with increasing concentration of watersoluble chitosans used in the formula. The film-formation time decreased accordingly. Moisture masks containing 0.5% U3 chitosan showed a similar consistency and film-formation time as those containing 2% methyl cellulose; however, the color of the moisture masks containing water-soluble chitosans was slightly orange-red. Moisture masks containing water-soluble chitosans showed superior water-holding capacity over those containing methyl cellulose. The higher the molecular weight of the water-soluble chitosans incorporated, the better the water-holding capacity of the resultant moisture masks.

A mathematical approach for the analysis of in vitro sun protection factor measurements

Abstract: A mathematical analysis of the spectral UV mono-protection curves of formulations based on organic absorbers is described, which derives a thickness profile for formulations applied to artificial substrates. To illustrate the potential of the analysis, profiles for an octyl methoxycinnamate formulation at three absorber concentrations applied to Transpore® tape and Vitro-Skin® are used to detect the experimental errors observed in the mono-protection curves for these systems. The variations of sun protection factors with concentration are then explored. The wide-ranging potential benefits of this type of analysis are described.

Investigations on the penetration of hydrolyzed wheat proteins into human hair by confocal laser-scanning fluorescence microscopy

Abstract: Hydrolyzed wheat proteins, of a type commonly used in hair toiletry products, were labeled by reaction with fluorescein isothiocyanate. Aqueous solutions were applied to untreated hair and also to hairs treated beforehand by permanent waving, by bleaching, or by relaxers The extent of penetration of the peptides into the hairs and their structural locations in them were determined by imaging transverse sections of the resin-embedded hairs with a confocal laser-scanning fluorescence microscope. Experimental evidence and arguments are mustered that the fluorescently labeled peptides, having been purified, provide a satisfactory model for studying the diffusional behavior of the native peptides in hair. Penetration of the hydrolyzed wheat proteins into all the hairs was extensive The main sites for occupation of the peptides were the endocuticle and in the cortex, the nuclear remnants (very intense), intermacrofibrillar matrix, and along the cell boundaries.

Antiwrinkle and skin-moisturizing effects of a mineral-algal-botanical complex

Abstract: Tests were carried out to compare the skin-smoothing and moisturizing effects of two cosmetic preparations, following two applications a day over a period of four weeks. The skin roughness parameter, Rz, was determined at the beginning and end of the study. The skin hydration was evaluated eight and twelve hours after cream application. At the end of four weeks, the cream enriched with 5% of Triple D Complex , composed of Dead Sea Mineral Skin Osmoter , Dunaliella salina algae extract and desert plants, had caused an average reduction of the skin roughness parameter by 43%. This effect was almost twice the improvement that was observed when a control cream was tested. From skin hydration results it can be concluded that the Triple D Complex may also be considered as an active moisturizing agent. The role of Dunaliella salina biomass enriched with Dead Sea minerals, as an active component of the complex, was examined separately. Several parameters that may affect the mineral biosorption and desorption were evaluated. The relatively low biosorption of calcium and magnesium into the algal biomass and the minimal tendency to release minerals from the biomass at the pH of skin leads to the conclusion that the role of these algae as a vehicle for the tested elements is limited. Similar results in skin smoothing, obtained in two distinct studies, using Dead Sea Mineral Skin Osmoter and Triple D Complex , suggest that Dead Sea minerals play a major role in the proven antiwrinkle effect.

Near-infrared spectroscopy: Applications in hair research

Abstract: We have evaluated the potential of NIR (near-infrared) spectroscopy as a tool in hair research. We find that this technique is ideally suited for measuring the relative moisture content of hair in situ under practical hair-grooming conditions. It also allows measurement of melanin absorption in the NIR region, where there is no interference from synthetic hair dyes. Thus, rapid evaluation of lift, the bleaching produced by oxidation dye products, can be performed on hair swatches as well as on live heads.

Advancements in Spectroscopic and Microscopic Techniques for Investigating the Adsorption of Conditioning Polymers onto Human Hair

Abstract: Adsorption of the polyquaternium-6 (Merquat®-100) conditioning polymer onto bleached human hair has been investigated using environmental scanning electron microscopy (ESEM), X-ray photoelectron spectroscopy (XPS), and secondary ion mass spectrometry (SIMS). ESEM is not limited to a high-vacuum environment, and therefore hair morphology could be studied under ambient and hydrated conditions. XPS gave elemental analysis on the surface of the hair, in addition to information on the chemical environment of the surface atoms. SIMS can produce high-resolution ion distribution images on the hair's surface. Both XPS and SIMS detected carbon, nitrogen, oxygen, and sulfur on the surface of the untreated bleached hair, all of which were attributed to the biological matrix. Silicon was also detected and its presence was attributed to either a previous silicone cosmetic application or to surface contamination. Due to the similar elemental composition of hair and Merquat-100, treatment of the hair with a phosphorus-labeled polyquaternium-6 cationic conditioning polymer was also investigated. XPS, with sensitivity of 1000 parts per million (ppm), could not detect phosphorus present from any adsorbed polymer, but SIMS, with 1-10 ppm sensitivity, allowed high-resolution images to be obtained that illustrated the adsorption of polymer onto the hair's surface.

Application of 4% and 8% glycolic acid to human skin in commercial skin creams formulated to CIR guidelines does not thin the stratum corneum or increase sensitivity to UVR

Abstract: Six months daily use of skin creams containing 4% and 8% glycolic acid with an SPF of 4 did not thin the stratum corneum or impair barrier function. There was no increased sunburn cell formation after UV irradiation, although the creams did contain sunscreen. The creams were applied twice daily for 24 weeks to the left or right volar forearms of ten women of phototypes I and II, using a balanced design. At 6, 12, and 24 weeks the treated forearms were exposed to one MED of simulated solar UVR. Punch biopsies taken 24 hours after irradiation showed no sunburn cells (SBCs). Cryostat sections of shave biopsies at 12 and 24 weeks showed no change in stratum corneum cell layers. Treated skin sites showed no increase in stratum corneum permeability as judged by no change in response to tetrahydrofurfuryl nicotinate skin challenge at 12 and 24 weeks.

Formulation and characterization of disperse systems as topical vehicles for odorous molecules.

Abstract: propylbetaine) and soya lecithin; microemulsions of linalool and several oils were also produced with the same surfactant mixtures. Both systems were stable over time, and miceIlar solutions offered some protection against autooxidation of the odorous molecules also due to the presence of soya lecithin that might behave as a naturally occurring molecule with antioxidant properties. The addition of several humectants (laureth-2, methyl gluceth-10, PEG-120 methyl glucose dioleate, and PEG-120 methyl glucose dioleate) to a miceliar solution allowed the complete elimination of alcohol and improved the rheological properties of the resulting systems. The challenge test of one of the miceIlar solutions of linalool revealed it to be autoprotected against microbial contamination as a consequence of the presence of the surfactants, hexylene glycol, and also, to some extent, linalool.

Synthesis of N-ethanol-2-(myristyl/palmityl)-3-oxo(stearamide/arachidamide) and its physical properties for a cosmetic raw material

Abstract: As a cosmetic raw material, N-ethanol-2-(myristyl/palmityl)-3-oxo(stearamide/arachidamide) (PC-9 s ) has been synthesized and its physical properties have been investigated. PC-9 s was synthesized by the reaction between alkylketene dimer (AKD) and 2-aminoethanol under the ethanol reflux system. The existence of intermolecular hydrogen bonding among the amide groups of PC-9 s s was confirmed by an FT-IR study. PC-9 s showed a very wide range of lamellar liquid crystal formation, with a mixture of fatty acid and cholesterol, and the lamellar structure was formed with a high content of fatty acid composition. The cross-polarized microscopic result of PC-9 s confirmed its intrinsic characteristic of lamellar structure formation. PC-9 s was verified to be non-toxic, non-irritable, and non-sensitizing in skin irritation tests on animals and humans. This intrinsic power to form the lamellar structure made it possible to form a multilamellar emulsion, which could have applications in the cosmetic and drug industries. An effective and economical synthetic pathway with high puriry and yield facilitates the industrial production of PC-9 s .

Measurement of interfiber adhesion

Abstract: Two methods of evaluating interfiber adhesive interactions are discussed. A single-point contact method measures the force of separation between two fibers that had been brought into contact with each other at a right angie under a defined contact pressure. After the application of topical treatments, reproducibility of the separation force along the length of the same fiber is poor. This has been attributed to the nonuniformity of surface deposition and to the uncertainty of the area of contact. The nonuniformity problem disappears when liquids are deposited on the fiber surface. In this case, capillary forces dominate the separation forces, although the uncertainty about the area of real contact between the two fibers still exists. The second method is a multipoint contact method in which the signal is much larger and which represents an average of the adhesive interactions between a single fiber and its neighbors in a hair assembly. The parameter measured is a "withdrawal" or pull-out force from a hair bundle with a defined packing density, which can help in the prediction of compressibility behavior describing hair body.

Stability enhancement of retinol through encapsulation in cationic vesicles

Abstract: Retinol is used in cosmetic formulations to help skin conditioning by increasing skin elasticity, thereby reducing wrinkles on skin surface. However, photo and air degradation of retinol make it difficult to formulate with. It is reported that retinols degrade faster if formulated in phospholipids. In our investigation, we formulated retinol in cationic bilayered vessels and compared its stability with both free retinol and with retinol formulated in lipid emulsions. Stability of retinol formulations (at 2% retinol) was tested at 50°C and under dark or light storing conditions. Samples were analyzed via reversed phase HPLC for retinol content. Our data indicated that formulation of retinol in cationic vesicles significantly improved stability of retinol even when stored under light. Cationic retinol vesicles also showed higher stability than the retinol in soy oil at 50°C.

Improvement in some physicochemical and biological properties of LG106W by inclusion complexation with β-cyclodextrin and its derivatives

Abstract: Synopsis 4-[3-Hydroxy-3-(2-hydroxy-5-methoxy-3,4,6-trimethyl-phenyl) propyl]-benzene-l,3-diol (LG106W) was synthesized as a novel skin-whitening agent. However, it has some formulation problems because of its low solubility in water and its instability. Inclusion complexation with cyclodextrins (CyDs) can be a tool for improving these problems. Inclusion complexes of LG106W with [3-cyclodextrin ([3-CyD) and its hydroxypropyl (HP-[3-CyD) and dimethyl (DM-[3-CyD) derivatives were evaluated by using a solubility method, a scanning electron microscope, a differential thermal analysis, and a powder X-ray diffractometer. We further investigated the cytotoxicity and in vitro skin permeation of the complexes. The relationship of inclusion complexation between LG106W and [3-cyclodextrins was clearly reflected in the magnitude of the stability constant (DM-[3-CyD > HP-[3-CyD > [3-CyD). The stability of LG106W was improved by inclusion complexation with HP-[3-CyD. The inclusion complexes had an activity similar to LG106W alone in the inhibition of melanin synthesis in B-16 melanoma cells, but showed lower cytotoxicity. The skin permeation of LG106W across excised hairless mouse skin was increased with the inclusion complexation, in the order ofDM-[-CyD > HP-[-CyD > [-CyD. From the above results, it is suggested that the [3-CyDs are reliable candidates for improving the availability of LG106W in cosmetic products.