Preservatives are added to pharmaceuticals, medical devices, personal care products, cosmetics and food products to inhibit the growth of microorganisms that are unintentionally introduced during the manufacturing process or during the use of multi-dose containers of products. Preservatives are commonly tested for in cosmetic testing. Some preservatives are also permitted in cosmetic health and safety codes. Cosmetics are mostly composed of various plant and animal extracts, oils and fats, water quality, and functional additives, which contain proteins and vitamins that can easily receive bacteria or microorganisms, and preservatives play an inhibitory role. However, preservatives in cosmetics tend to cause skin allergies. On the one hand, preservatives can accumulate on human skin, and when accumulated to a certain amount, it will instead accelerate skin aging; on the other hand, preservatives also accelerate pigmentation and dullness of skin. Therefore, CD Formulation conducts preservative tests to quickly analyze the preservative content as well as its efficacy.
HPLC method for the determination of preservatives
The HPLC method is used for the determination of parabens, benzyl alcohol, benzoic acid, carcinol, and IPBC preservatives in cosmetics, with the advantages of low detection limit, high analytical sensitivity, and simultaneous separation and detection of multiple preservatives.
IPBC is an amino acid derivative, which is a new type of preservative for cosmetics. The determination of IPBC in cosmetics by FID-GC method showed a good linear relationship between peak area and sample concentration with the correlation coefficient >0.995.
CD Formulation can be used for the quantitative determination of preservatives in cosmetics. Currently, we can do the corresponding tests for the commonly used preservatives in cosmetics, which are: methylisothiazolinone; benzyl alcohol; phenoxyethanol; methyl 4-hydroxybenzoate; benzoic acid and ethyl 4-hydroxybenzoate, etc. Also, we can perform preservative challenge tests to assess efficacy by challenging preparations with the appropriate microbial range (in the final container if possible). Samples are collected at set time intervals and the number of microorganisms that are not killed is counted. If there is no increase or a significant decrease in the number of organisms within a certain time frame, the preservative properties are sufficient.
Preservatives are needed to protect cosmetic products from microbial contamination, to protect consumers from infection, to ensure product safety, and to extend shelf life. If cosmetics do not add preservatives, the product is likely to precipitate, cloudy, color change, etc. Some products may have a change in pH, broken milk, lumps, foam, odor, mold and other quality problems. Therefore, the mechanism of action of preservatives is to inhibit the survival or reproduction of microorganisms, to ensure the safety of cosmetics in storage, use period.
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