Cosmetic degradation

Some plastics are subject to microbial attack that can cause polymer staining. The staining can affect the aesthetic value, shorten the service life of the product, or cause premature replacement of the article. 

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Contraction in the number of EPA-allowed biocides has heightened efforts to develop naturally derived preservatives and microorganisms capable of countering microbial degradation. Neem oil A. dirachta indica seed extract) has been featured as an exceptional natural candidate for the preservation of cosmetic products. Naturally derived chemicals with antimicrobial properties have been used since antiquity as preservatives. However, displacement of successhil synthetic products by natural products in preservatives of any category remains to be witnessed. 

The concentrate derived from ultrafiltration is usually a thick colourless gel containing about 4-8% solids. This must contain an antimicrobial agent to inhibit microbial growth and biological degradation. The type of antimicrobial agent used depends on the particular application for the exopolysaccharide. For example, the nature of file antimicrobial agent is less critical for industrial applications, such as enhanced oil recovery, than for use in cosmetics. 

There are large numbers of naturally occurring representatives, especially of pyrrole that include the important polypyrroles (porphyrins and corrins), and the nitropyrrole antibiotics such as pyr-rolomycins and pyrroxamycin. Derivatives of furan have been used as fungicides and A-vinylpyr-rolidone is an important monomer for the production of blood plasma extenders and for cosmetic applications. On account of the similarity in the pathways for the aerobic degradation of monocyclic furan, thiophene, and pyrrole, all of them are considered here. Anaerobic degradation of furans is discussed in Part 2 of this chapter. 

Triclosan is a broad spectrum antibacterial agent with antifungal and antiviral properties, widely employed in personal care products such as soaps, shampoos, toothpastes, and cosmetics [40]. Fungal-mediated degradation studies have been mainly performed by means of enzymatic processes, although a couple of whole cell transformation reports are available. 

Two of the most widely used and detected UV filters in the environment and WWTPs are BP3 and 4-MBC. Thus, they were the selected compounds to study individually their degradation by fungi [44, 49]. Studies with BP1, not only a BP3 metabolite but also an industrial UV filter (but its use in cosmetics is not allowed) itself have also been performed. Studies in liquid media allow a better analysis and monitoring of many parameters, both the contaminant concentration and the fungal metabolic state such as glucose consumption and enzyme production. In these studies, the degradation process was performed with the fungus in form of pellets. 

Sucrose Esters. Sucrose esters have industrial interest in the area of surfactants, " bleaching boosters, cosmetics, and fat substitutes. Synthetically prepared octa-fatty acid esters of sucrose have similar properties as the normal triglycerides, yet are not degraded by Upases, which entailed their marketing as noncaloric fat substitutes—after being approved by the U.S. Food and Drug Administration under the name Olestra or Clean . ... 

Sodium fatty acid ester sulfonates are known to be highly attractive as surfactants. These have good wetting ability and excellent calcium ion stability as well as high detergency without phosphates, and are used in powders or liquids. They can also be used in the textile industry, emulsion polymerization, cosmetics, and metal surface fields. Moreover, they are attractive because they are produced from renewable natural resources and their bio degradability is almost as good as alkyl sulfates (134—137). 

Essential oils are also influenced by legislation that regulates specific products that may contain these oils, e,g,. the U.S. Food, Drug, and Cosmetic Act and the European Community Cosmetic Directive. Essential oils would not be anticipated to be of environmental concern, considering that they originate from botanical sources, Thus, natural processes exist to degrade essential oils and recycle their components effectively in the environment,... 

Because the objective of this process is the preservation of the lyophilized material, the presence of collapsed material is suspect. Collapse may simply be considered a cosmetic defect. When the collapsed material exhibits an increased reconstitution time or poor solubility, the presence of collapse becomes more than just a cosmetic defect. If, however, the collapsed material retains a higher amount of residual water, where this water becomes involved in degradation of the product through hydrolysis, then there is a more serious concern. The presence of a significant amount of residual water may promote degradation of the product, such that the assay falls outside of the compendial limits. There would also be a concern for the toxicity or an influence on the therapeutic effectiveness of the product. Both potential results should be considered during product development. 

Rawlings, A.Y., et al. 1994. Abnormalities in stratum corneum structure, lipid composition, and desmosome degradation in soap-induced winter xerosis. J Soc Cosmet Chem 45 203. 

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