Effect of Commonly Used Cosmetic Preservatives on Healthy Human Skin Cells

In Vitro Study of Cyano-Phycocyanin Release from Hydrogels and Ex Vivo Study of Skin Penetration

BACKGROUND

This study explored the most suitable materials for incorporating cyano-phycocyanin (C-PC) into hydrogels, focusing on maintaining the C-PC's long-term structural integrity and stabilityNext, the release of C-PC from the hydrogels and its skin penetration were investigated.

METHODS

A series of 1% (w/w) C-PC hydrogels was prepared using various gelling agents and preservatives. Spectrophotometric measurements compared the amount of C-PC in the hydrogels to the initially added amount. After selecting the most suitable gelling agent and preservative, two C-PC hydrogels, with and without propylene glycol (PG) (Sigma-Aldrich, St. Louis, MO, USA), were produced for further testing. In vitro release studies utilized modified Franz-type diffusion cells, while ex vivo skin-permeation studies employed Bronaugh-type cells and human skin. Confocal laser scanning microscopy analyzed C-PC accumulation in the skin.

RESULTS

The findings demonstrated that sodium alginate (Sigma-Aldrich, St. Louis, MO, USA), hydroxyethyl cellulose (HEC) (Sigma-Aldrich, St. Louis, MO, USA), and SoligelTM (Givaudan, Vernier, Switzerland) are effective biopolymers for formulating hydrogels while maintaining C-PC stability. After 6 h, C-PC release from the hydrogel containing PG was approximately 10% or 728.07 (±19.35) μg/cm2, significantly higher than the nearly 7% or 531.44 (±26.81) μg/cm2 release from the hydrogel without PG (p < 0.05). The ex vivo qualitative skin-permeation study indicated that PG enhances C-PC penetration into the outermost skin layer.

CONCLUSION

PG's ability to enhance the release of C-PC from the hydrogel, coupled with its capacity to modify the skin barrier ex vivo, facilitates the penetration of C-PC into the stratum corneum.

Fabrication and characterization of antibacterial nanofiber membranes modified with chitosan and imidazolidinyl urea for potential use in biological waste treatments

An ion exchange nanofiber membrane (AEA-COOH) was developed from polyacrylonitrile (PAN) nanofibers through chemical hydrolysis. It was further modified by grafting chitosan (CS) onto its surface, creating the AEA-COOH-CS membrane. Then, both membranes were covalently immobilized with imidazolidinyl urea (IU), resulting in AEA-COOH-IU and AEA-COOH-CS-IU membranes. This study analyzed their physical properties, antibacterial efficacy (AE), and reusability. Optimal conditions were identified: 50 kDa molecular weight of chitosan, pH 8 for IU modification, and 0.05 % IU concentration. The AEA-COOH-IU membrane achieved 96.15 % AE against Escherichia coli at an initial concentration of 2.0 × 107 CFU/mL, while the AEA-COOH-CS-IU membrane achieved 100 % AE. The AEA-COOH-CS-IU membrane maintained 95.04 % efficacy over 5 cycles, demonstrating superior durability. As a result, the AEA-COOH-CS-IU membrane has high potential for environmental applications such as water purification and wastewater treatment. Its robust antibacterial properties and reusability suggest a significant impact on ensuring cleaner water resources and prospective uses in the biomedical field, including medical device coatings and healthcare applications.

Microbiological Quality Assessment of Skin and Body care Cosmetics by using Challenge test

Cosmetic products may be exposed to microbial contamination during storage or transport, and to avoid the risk of microbial growth, manufacturers add preservative compounds as a protection for the product from spoilage. The Microbial Challenge test is a procedure to evaluate the preservative efficacy by challenging the product with testing microorganisms to determine the quality of preservation. In this study, thirty-two cosmetics products used for body and skin care were collected from markets and pharmacies in Mecca region, these products are subjected to microbiological analysis, results show that most samples are contaminated except six samples. Non contaminated samples were subjected to European Pharmacopeia 7.0 standards. Results show that two samples, foaming gel and body and face cream are failed to demonstrate the required microbiocidal effect against the S.aureus test species, results recorded 1.21 x 105 and 6.80 x 105 (CFU/ml) respectively at the second day of incubation, other products: shower gel, hand wash, body lotion and shampoo demonstrate that required microbiocidal effect against the test species during day 2, 7, 14 until day 28th. The microbial count number is less than 10 during all incubation periods. To prevent contamination in cosmetics, manufacturers are required to add a good preservative system to the products and examine them before sale. Due to the high percentage of microbial contamination in cosmetics in Mecca region and for consumers safety, this study is prepared.

Toxic Ingredients in Personal Care Products: A Dermatological Perspective

Environmental dermatology is the study of how environmental factors affect the integumentary system. The environment includes natural and built habitats, encompassing ambient exposure, occupational exposures, and lifestyle exposures secondary to dietary and personal care choices. This review explores common toxins found in personal care products and packaging, such as bisphenols, parabens, phthalates, per- and poly-fluoroalkyl substances, p-phenylenediamine, and formaldehyde. Exposure to these toxins has been associated with carcinogenic, obesogenic, or proinflammatory effects that can potentiate disease. In addition, these compounds have been implicated as endocrine-disrupting chemicals that can worsen dermatological conditions such as acne vulgaris, or dermatitis. Certain pollutants found in personal care products are not biodegradable and have the potential to bioaccumulate in humans. Therefore, even short-term exposure can cause long-lasting issues for communities. The skin is often the first point of contact for environmental exposures and serves as the conduit between environmental toxins and the human body. Therefore, it is important for dermatologists to understand common pollutants and their acute, subacute, and chronic impact on dermatological conditions to better diagnose and manage disease.

Machine learning assisted rational design of antimicrobial peptides based on human endogenous proteins and their applications for cosmetic preservative system optimization

Preservatives are essential components in cosmetic products, but their safety issues have attracted widespread attention. There is an urgent need for safe and effective alternatives. Antimicrobial peptides (AMPs) are part of the innate immune system and have potent antimicrobial properties. Using machine learning-assisted rational design, we obtained a novel antibacterial peptide, IK-16-1, with significant antibacterial activity and maintaining safety based on β-defensins. IK-16-1 has broad-spectrum antimicrobial properties against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans, and has no haemolytic activity. The use of IK-16-1 holds promise in the cosmetics industry, since it can serve as a preservative synergist to reduce the amount of other preservatives in cosmetics. This study verified the feasibility of combining computational design with artificial intelligence prediction to design AMPs, achieving rapid screening and reducing development costs.

Nanotechnology-Based Approaches for Cosmeceutical and Skin Care: A Systematic Review

Cosmeceuticals have gained great importance and are among the top-selling products used for skin care. Because of changing lifestyles, climate, and increasing pollution, cosmeceuticals are utilized by every individual, thereby making cosmeceuticals a fruitful field for research and the economy. Cosmeceuticals provide incredibly pleasing aesthetic results by fusing the qualities of both cosmetics and medicinal substances. Cosmeceuticals are primarily utilized to improve the appearance of skin by making it smoother, moisturized, and wrinkle-free, in addition to treating dermatological conditions, including photoaging, burns, dandruff, acne, eczema, and erythema. Nanocosmeceuticals are cosmetic products that combine therapeutic effects utilizing nanotechnology, allowing for more precise and effective target-specific delivery of active ingredients, and improving bioavailability.

Pure White Cell Aplasia Associated With Long-Term Unprotected Exposure to High Concentrations of Benzalkonium Chloride and 2-Phenoxyethanol

Pure white cell aplasia (PWCA) is a very rare hematological disorder with a nearly total absence of granulocytes and their precursor cells. While the disease is rarely diagnosed incidentally in otherwise asymptomatic individuals, most patients suffer from sometimes life-threatening infections. Due to its very low incidence, the precise pathomechanism of PWCA still needs to be elucidated. While most cases reported in the literature have been associated with an underlying thymic or autoimmune disease, some other factors including the intake of certain drugs such as antimicrobial agents or immune checkpoint inhibitors have been identified as potential triggers. Since PWCA is commonly refractory to treatment with granulocyte colony-stimulating factors (G-CSF), the main focus lies in identifying and eliminating the underlying trigger. Here, we report a unique case where the development of PWCA in a 56-year-old man with an upper respiratory tract infection has to be attributed to the long-term unprotected exposure to an industrial detergent containing high concentrations of the preservatives benzalkonium chloride (BAC) and 2-phenoxyethanol (2-PE). As a matter of fact, certain hematotoxic potential has been described in the literature for both BAC and 2-PE.