Water can be used as an ecological lubricant base if it is possible to select additives which can beneficially modify its tribological and corrosion properties. Additionally, those additives should not be harmful to human health and the natural environment. These conditions limit or even eliminate the possibility for the application of the additives used in traditional oil bases as they are insoluble in water and often toxic. Alkyl polyglucosides (APGs) have been suggested as additives improving lubricating properties of water. They are biodegradable and do not have to be recycled. They exhibit surface activity. They produce micelles at low concentration and lyotropic liquid crystals at high concentration. Two types of alkyl polyglucosides differing in alkyl chain lengths and degrees of polymerization were used in this investigation. Tribological tests were carried out using a ball-on-disc T-11 tester. The balls were made of steel, whereas the discs were made of steel, aluminium oxide, zirconium oxide, polyamide and poly(methyl methacrylate). The description of the device and the methods has been given in the literature (Szczerek and Tuszyński in TriboTest 8:273–284, 2002). The addition of APGs improves the lubricating properties of water. The relative decrease in motion resistance and wear depends both on the type of friction couple and on the kind of alkyl polyglucoside used. The tribological test results obtained were correlated with the activity of APGs measured as wettability of friction couples by their solutions.
Surfactants, which are the basic ingredients in washing cosmetics, can cause skin irritation. In the case of washing cosmetics intended for children, it is necessary to select the composition in such a way as to ensure maximum reduction or even elimination of the irritant effect of the final product. The paper attempts to improve the safety of bath cosmetics for children by introducing: collagen amino acids (150 Da), hydrolysed collagen (12000 Da) and soluble collagen (300 000 Da). Zein value, bovine albumin, and human keratinocyte cell line studies have shown a significant decrease in the irritant potential of the compositions following the introduction of the proposed additives, which is more pronounced with the increase in the molecular weight of marine collagen. An important part of this work is a mechanism proposed by the authors, according to which the addition of the proposed additives can increase safety of the application of cosmetics for children.
Animal research undoubtedly provides scientists with virtually unlimited data but inflicts pain and suffering on animals. Currently, legislators and scientists alike are promoting alternative in vitro approaches allowing for an accurate evaluation of processes occurring in the body without animal sacrifice. Historically, one of the most infamous animal tests is the Draize test, mainly performed on rabbits. Even though this test was considered the gold standard for around 50 years, the Draize test fails to mimic human response mainly due to human and rabbit eye physiological differences. Therefore, many alternative assays were developed to evaluate ocular toxicity and drug effectiveness accurately. Here we review recent achievements in tissue engineering of in vitro 2D, 2.5D, 3D, organoid and organ-on-chip ocular models, as well as in vivo and ex vivo models in terms of their advantages and limitations.
The study investigated the effect of chamomile extract obtained in supercritical carbon dioxide conditions on the basic properties of pharmaceutical ointments. A total of five formulations were designed and prepared, differing in the weight ratio of sunflower oil to chamomile extract (5:0, 3.5:1.5, 2.5:2.5, 1.5:3.5 and 0:5). An increase in the concentration of chamomile extract was found to be accompanied by a decrease in hardness, adhesive power and flow limit. Based on viscosity measurements it was shown that ointments containing the hydrophobic plant extract under study were prone to larger drops in viscosity under the effect of the set shear rate. It was determined that from the viewpoint of ointment spreadability and application to the skin, the optimum concentration of chamomile extract for the studied formulations should be within the range of 1.5-2.5%. Furthermore, the addition of chamomile extract to ointments was found to give samples a yellow-green color. Green was observed to be the dominant color, and its saturation and shade varied for different formulations.
The aim of the study is to demonstrate the effect of the addition of vegetable oils rich in EFA on the effectiveness of hydrophobic skin protection preparations intended for work in the wet environment. The research hypothesis assumes that the increase in the concentration of vegetable oils in the formula of protective preparations improves their spreadability on the skin, thus translating into acceptance of the preparations by users, improving their quality of life, strengthening the barrier functions of the skin without reducing the effectiveness of the protective action. The distribution capacity of pure vegetable oils is determined using instrumental analysis and sensory analysis. Also, TEWL tests are used to evaluate their occlusal properties. For protective preparations based on them, the distribution capacity is tested by in vitro methods as well as in vivo tests and sensory analyses are performed. The effectiveness of the tested preparations is measured by tests concerning absorbability, occlusion capacity and washability. The results are analyzed and compared, and a correlation matrix is developed to establish the relationship between sensory and instrumental measurements. The effectiveness of the preparations depends on the type of oil (its spreadability and viscosity) and the amount in the formulation. Practical Applications: For hydrophobic preparations of ointment type, there is a possibility to implement such instrumental techniques as: determination of preparation consistency by means of a cone, ability to distribute by means of parallel plates, but also determination of preparation viscosity by rheological methods. Viscosity, spreading ability, and oil occlusion ability are the most important parameters that should be taken into account when we design hydrophobic skin protection preparations intended for the works in the wet environment.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.