Development of water resistance OW sunscreen cream using chitosan polymer emulsifier

China Detergent Industry bookmark1 Latest Cosmetic Formulation Technology 4 Deacetylation of Poly Acrylic Acid Sorghum 3 Emulsification Scratch Development Water Resistance/w Sunscreen ç­±Yoshihisa Makoto Yoshikazu Sakai Kasumi (Chitosan) are all compatible with human body Good natural polymer. Such natural polymers have a variety of effects: moisture retention. Antibacterial, wound healing, drug Xu Fang and lower cholesterol. It can be used as raw material for medical materials and health foods. In the cosmetics field. Derived from chitin and chitosan as skeletons. As a functional raw material. Has entered the practical stage. Until now. The main function of its application is a moisturizing effect similar to that of hyaluronic acid. In recent years. High added value to new effects of chitin and chitosan derivatives. With new understanding. One example is the application in sunscreen products.

The main efficacy as a sunscreen product is to inhibit the SPF value and PA value caused by water or sweat. To ensure the product's water resistance. The emulsifier type of the product is mainly a "water-in-oil MW/O" type, but due to the formation of a film of oil on the film, the disadvantages such as the deterioration of the skin care effect such as usability and moisture retention are caused, and the oil film is sealed. It may also cause the production of sebaceous disorders such as acne and face "brightness." The use of the outer phase of water as an "oil-in-water" (/W) dosage form feels good. The oil film has a low plugging property. However, it is difficult to maintain a high SPF value because of the contained hydrophilic surfactant. Product water resistance is also a major drawback. It has been reported that the water resistance test was evaluated by the FDA method. The SPF value after water washing is only 15% of the SPF value before washing. This article uses a novel chitin derivative with a cationic polymer emulsifying function as an emulsifier. Formulated with excellent water resistance.

Use a sunscreen that feels ''water'' /W.

The use of macromolecular rituals for the production of alpha-spermicidal organisms. 2-1. Recent development and emulsification properties of novel chitin derivatives. Research on chitin derivatives with excellent emulsification and biodegradability of polymers is underway. The chemical structure of a novel chitosan derivative Partially-C14-ChitosanPCA (abbreviated as PMCP) jointly developed by Prof. Ji Shou-shou of Shizuoka Prefectural University and others was shown in Figure 丨. When the introduction ratio of myristoyl (tetradecanoyl) was adjusted to 10-15%, the characteristics of pyrrolidone carboxylic acid as the counterion was shown.

2-2. Stabilized O/W type emulsion system containing UV agent PMCP is treated with a conventional homogenizer. Various oil agents (eg non-polar oils, polar oils, silicone oils, fluorochemical oils) can be added. No low molecular surfactant is added. Can form an average particle size of 2-1ll-im. O/W-type cation with good stability USKSS 2004 sixth science and technology bookmark4 Chinese detergent industry-only PMCP and UV agent (p-methoxy cinnamic acid The fluorescent microscopy image of the emulsion system formulated with ethylhexyl ester is shown.

The fluorescent observation shows that the oil-like UV agent surrounds the inside of the ball. The myristoyl group present on some of the UV agents is fixed inside the sphere. The interface of the UV agent is coated. And form an emulsion. Due to the electrostatic repulsion of the charged amine groups, the stability of the emulsion is further increased.

PMCP can evenly disperse the UV-dispersed L agent (titanium dioxide). After the titanium dioxide-containing PMCP aqueous solution is homogenously dispersed, a stable and uniform dispersion of titanium dioxide can be prepared. If aqueous solutions of water-soluble thickening macromolecules (carboxyethyl polymers, CYP or xanthan gum), which are widely used in cosmetics, are used, titanium dioxide will obviously condense.

The formulation of the product has the following disadvantages: poor water resistance; the incorporation of a large amount of highly polar UV absorbers can irritate the skin: the incorporation of UV-dispersible agents can cause unstable conditions such as powder coagulation. The use of PMCP can successfully solve these ills.

Even with the addition of a large amount of UV absorbers or UV dispersants, it is possible to formulate a good/W type preparation with stability and safety (SPF: resistance to w-type sun care products with "Shuilingling" feeling.) Evaluation of water-resistance SPF UV absorbers and UV dispersants were added to the PMCP emulsifying system to prepare an O/W sun care preparation, and this PMCP emulsification system was compared with a general/W emulsification system. Two preparations were coated on the inside of the volunteer's anterior wrist, and after washing, the residual amount of UV absorber was compared. The residual amount of the general/W surfactant emulsification system was only 10-20%. The PMCP emulsifier system The residual amount is as high as more than 90%, achieving the excellent W/O level of the traditional water resistance, and then using the FDA China Detergent Industry bookmark8 □ The cairarial evaluation a The relative evaluation of the water lingering sensation Non-stick feeling —— U - The skin does not have a heavy feeling u.

The method of satisfaction of 40) tests the water resistance SPF. The results are as shown. The two formulations with the addition of a UV absorber and a UV-dissolving agent exhibited almost no change in SPF after treatment with water twice for 20 minutes, and were considered to have excellent water resistance (sustainability). The mechanism (reasoning) of the water resistance of Utra is as shown.

A UV absorber and a UV dispersant were added to the PMCP emulsification system to prepare a water-resistant O/W sun care preparation of SPF33. This formulation was evaluated according to the test and 40 volunteers were females aged 20-40 years. The use period is 2 weeks. In the middle. Said: In absolute evaluation. "Slightly satisfied" above ratio. And when compared with ordinary products, "slightly better than" the above ratio. From the results, the use of traditional W/O sun care formulations is not perfect. For example: There is no feeling of "water spirit", and its advantage is only excellent moisture retention.

Questions about security. The PMCP emulsification system containing a UV absorber was compared with the irritancy of a surfactant emulsification system. First, a stimulatory test was performed using a three-dimensional model of human skin cells (TESTSKIN Toyobo). At the same time, 15 volunteers responded to the irritant reaction caused by the UV absorber. Then compare the two tests. Assessed by TESTSKIN: emulsified system with surfactant. In the early stage of stimulation, it will promote the production of an irritant substance IL-1. PMCP emulsification system does not have this phenomenon. In addition, emulsified formulations containing 10-12% UV absorbers were tested continuously. Compared with the general W/O emulsified preparations, the PMCP emulsified preparations showed a significant reduction in irritation.

Concluding remarks This article describes the use of cationic chitosan polymeric emulsifiers for their usability and safety. Excellent water resistance /W type sun care formulations. Since the upper limit value of the SPF of the sun care preparation is set to 50+, so. Not only does it require a high SPF value but it also gives the product a "water spirit" comfort. In order to develop a unique style of products. from now on. The research and development of new raw materials and formulation technologies for O/W sun care formulations will continue to develop rapidly.