Journal of cosmetic science最新文献

Subversion bias, a type of selection bias, through manipulation of subject recruitment compromises data validity. This study explores the possibility of subversion bias in sunscreen sun protection factor (SPF) testing. It has been established that subjects with lower minimal erythemal dose (MED) values exhibit higher sunscreen SPF values. Consistency of this response is determined in subjects who participated in multiple sunscreen efficacy clinical trials. All trials determined the SPF of the sunscreen standard P2. Of the 652 subjects with greater than three observations (n = 286), 35 subjects consistently had values either well above (n = 29) or below (n = 6) the average SPF value of the dataset (15.6 ± 1.2). The difference between the average SPF by the subject exhibiting the highest average SPF for P2, 19.8 ± 0.9, and the subject exhibiting the lowest average SPF for P2, 12.3 ± 2.6, is 7.5 SPF units, or 61%. Recruitment strategies based on historical SPF values for an individual would be considered subversion bias. Foreknowledge of those subjects with consistent results either in favor or not in favor of SPF testing outcomes could be exploited and would provide a reason for variation in results among testing facilities.

Aging is a natural phenomenon that affects the whole body, including the skin. As we age, endogenous and exogenous factors cause our skin to become thinner, paler, and wrinkled. Although the underlying mechanisms of the pathogenesis of skin aging are not entirely known, multiple pathways have been proposed. Inflammaging has recently emerged as a pathway that correlates aging and age-related diseases with inflammation. This review discusses the role and pathways of inflammaging that lead to skin aging. Moreover, strategies and current topical approaches for skin-aging treatment are discussed. Studies over the past 10 years suggested that DNA damage and oxidative stress are the most critical mechanisms in skin aging, and both are interlinked with inflammaging. Several treatments for skin aging have been considered such as antioxidants, hormone replacement therapy, and vitamins. To deliver anti-aging agents topically, researchers adopted numerous approaches to enhance skin penetration including physical, chemical, or biomaterial enhancers and carrier-based formulations. In recent years, consumers' demands for anti-aging products have considerably risen, leading to robust growth in the anti-aging market. Therefore, further in-depth studies are necessary to understand skin-aging mechanisms and evaluate the efficacy of anti-aging products to protect consumers worldwide by providing them safe and effective over-the-counter skin-aging formulations.

Excessive and daily inhalation of talcum, a main ingredient of face powders, causes pulmonary talcosis, which has led to the replacement of talcum with safer natural ingredients. RiceSorb^®, or Oryza sativa starch from Japanese rice, was used as an alternative owing to its nontoxic and excellent oil absorption capacity. The objectives of the present work were to formulate loose face powders from RiceSorb^® and to investigate the physicochemical properties of the prepared formulations. Five formulations of loose face powders were prepared by varying the ratios between talcum and RiceSorb^®: 4:0 (FT0), 3:1 (FT1), 1:1 (FT2), 1:3 (FT3), and 0:4 (FT4). The physicochemical properties were evaluated mainly based on USP 41 and NF 36 such as morphology by using a scanning electron microscope, bulk density, flow property (angle of repose), moisture content (MC), and pH. The stability of the formulations were also performed at ambient temperature and 45°C for 2 months. The formulations had pH 6.90-8.62, bulk density 0.33-0.49 g/ml, and an angle of repose 30°-41°. Overall, the formulations which contained only RiceSorb^® (FT4) or higher proportion of RiceSorb^® (FT3) had finer particles, lower bulk density, pH, and angle of repose than those of the formulations containing high proportion of talcum: FT0 and FT1. Under storage conditions for 2 months, the formulations containing high proportion of RiceSorb^® exhibited noticeably increased MC and angle of repose. However, the other physicochemical properties were somewhat the same. The present results suggest the applicability of RiceSorb^® for loose face powders.

Lecythis pisonis nuts are rich in tocopherols, polyphenols, and fatty acids, and hence, the quality of oil was analyzed for use in the elaboration of skin cream. Nut oil was extracted with hexane in a Soxhlet apparatus. The quality and safety of the oil were tested by using established protocols from Adolf Lutz Institute. Three concentrations, 1%, 5%, and 10%, of oil were incorporated into a formulated cream. The oil formulations were evaluated for their stability, organoleptic characteristics, pH, viscosity, spreadability, challenge test, cellular viability, and their response to microbial contamination, as recommended by the National Health Surveillance Agency (ANVISA). Quality analysis demonstrated the high quality of the obtained oil, with no traces of heavy metals and no toxic effects on ingestion. The cream containing L. pisonis nut oil is stable, has an effective preservative system, and is considered safe for use because it presented no toxicity in human cells. A stabilizer is required to maintain the pH in the range suitable for a body cream. Of the formulations tested, the cream containing 5% nut oil was the most stable and had presented the best organoleptic characteristics.

An attempt has been made to evaluate and quantify the moisturizing efficacy of cosmetic products by dynamic vapor sorption method. The possibility of quantifying this effect by the application of the second law of thermodynamics to sorption hysteresis has been demonstrated. The results show that the ordinary conditioner actives in rinse-off formulations show limited moisturizing capabilities. However, specially formulated products can show, quantifiably, both moisturizing and desiccating effects. From the Brunauer, Emmett and Teller (BET) theory, total pore volume obtained from the literature by nitrogen adsorption, and the sorption data from this work, it has been possible to show that the sorbed water in hair does not distribute uniformly in the hair. This is in agreement with the X-ray diffraction measurements and the more recent work on small angle neutron scattering on D₂O-saturated hair.

Caffeine is extensively used in cellulite and hair growth cosmetic products. Regulations in the field of cosmetics require manufacturers to list caffeine in the ingredient list on product labels, but its exact content in these products is not declared. On the other hand, daily exposure to caffeine from all sources may approach health reference values. For that reason, it is important to know the exact caffeine content in products for skin and hair care. Cosmetics are often viscous or semisolid products of very complex chemical composition. To analyze caffeine in these complex sample matrices by liquid chromatographic methods, an extraction step is often necessary. This article presents the applicability of the solid-phase extraction (SPE) procedure for the caffeine extraction and high-performance liquid chromatography (HPLC) determination in anticellulite gels, shampoos, and hair balsam. The samples of gels were centrifuged after ammonia addition to precipitate carbomer. In cellulite reduction, gel caffeine content was found to be in the range of 0.7-1.7%, whereas in the hair-care products, it was about 1.0%.

This review summarizes the evidence on the protection against skin cancer afforded by sunscreen. Solid evidence can come only from randomized controlled trials, despite a multitude of case-control and cohort studies that have addressed the issue, because observational evidence is intractably confounded since those at highest risk of skin cancer are naturally the highest users of sunscreen. Findings of the single human trial conducted in subtropical Australia during 1992-1996 with follow-up to 2014 showed that the application of a broad-spectrum, sun protection factor 16 sunscreen to exposed skin of the head and neck and upper limbs at least 3-4 days per week in adulthood can reduce the risk of developing cutaneous squamous cell carcinoma and melanoma but does not appear to reduce the risk of basal cell carcinoma (BCC) overall, although it may reduce the occurrence of multiple BCCs over time.

Skin exposure to solar radiation can cause many adverse effects. In addition to the sun protection factor (SPF), a parameter associated with Ultraviolet B (UVB) protection, significant evidence emphasized the crucial importance of a well-balanced protection against ultraviolet A (UVA) and for some indications, against high-energy visible light. Synergy between UV filters and filter photostability together with film-forming ingredients such as polymers that ensure the homogeneous distribution of UV filters on the skin are key factors to avoid UVA- and UVB-provoked detrimental effects of solar radiation. Clinical studies mimicking real conditions of use have been performed. The results show that a well-balanced sunscreen with at least an SPF-to-UVA protection factor ratio < 3 provides the most effective protection against DNA damage, skin photoimmunosuppression, photodermatoses, and pigmentation disorders. In addition, cosmetically pleasant sunscreens allow a sufficient amount to be applied and re-applied by consumers, ensuring continuous and even coverage of the exposed skin.