Influence of Different Surfactants on Efficacy and Storage Stability of Sunscreen Emulsions

Autor: Jia-Jen Lin, 林佳蓁
Rok vydání: 2013
Druh dokumentu: 學位論文 ; thesis
Popis: 101
Ultraviolet light is an important factor to cause wrinkling, premature aging of the skin, hyperpigmentation macules or even skin cancer. People should protect their skin from UV-induced damage. It is well known that suncreams’ application is a good way to avoid the skin damage due to the overexposure to the sunlight during daytime. This led to the increasing needs for suncreams in the market. A series of suncreams were approved and applied, but some of them can cause photodegradation under extreme conditions such as UV radiation and evolved temperature. It will result in physical instability and the lower efficacy of the suncreams. Hence, the goal of the study is to optimize suncreams that can promise storage stability, constant efficacy of the product, and the safety of consumer’s application. In order to formulate elegant suncreams, four different types of surfactants were selected as emulsifiers. They are GMS(Glyceryl Monostearate)、CG 90(Cetearyl Glucoside)、CD pol(CetylDimethiconeCopolyol) and RADIAMULS POLY2253K(Polyglyceryl-3Polyricinoleate)/RADIASURF7758(SorbitanIsostearate). Two chemical UV filters, PMCX (Octyl Methoxy Cinnamate), P1789 (4-Tert-Butyl-4´-Methoxy Dibenzoyl Methane) were examined because they were the most widely used UV filters. In the beginning we use the surfactants to formulate four different emulsions without UV filters as a control. And then we performed studies using the incorporation of single filter and a combination of the two filters into each control emulsion containing various kinds of emulsifiers and investigated their physicochemical properties including viscosity, rheological behavior, particle size and distribution, and intro SPF efficacy during typical accelerated test. In addition, a photostabilizer was added to stabilize SPF value of the suncreams. The suncreams’ properties were compared with commercial products. In relating to physicochemical properties, the results showed that all the formulated suncreams exhibited shear-thinning rheological behavior before and after accelerated test. Obviously, they can provide good skin feel when they are applied onto the skin. Among the emulsifier systems, CG90 exhibited better storage stability than other three emulsifiers. The order of the storage stability is CG90(49days)>R2253/R7758(35days)>CDpol(7days)=GMS(7days).But R2253/R7758 system possess the smaller change (η/η=0.77 at 35 days) in viscosity than CDpol system (η/η=0.55 at 7days). Relating to the particle size, CDpol has the largest variance and show the occurrence of coalescense after accelerated test. In addition, the particle size increased with increasing amount of UV fitters in sunscreen products in CG90、R2253/R7758 and GMS system. On the other hand, the efficacy of all the sunscreen products was measured. These results indicate that the efficacy was well correlating with the amounts of the used UV filters. Regardless of incorporating single UV filter or a combination, CG90 system contributed a higher SPF (19.00 of SPF at 10% PMCX) and a better correlation coefficient (r=0.998 for single PMCX; r=0.990 for a combination) than CDpol system (14.80 of SPF at 10% PMCX; r=0.969 for single PMCX; r=0.960 for a combination). In addition, all the obtained suncreams with a combination exhibited a larger change in SPF before and after accelerated test than those with single PMCX. Besides, we found that the efficacy of the sunscreen formulations early decreased under accelerated test and photo-aging. Fortunately, it was found that a photstabilizer can contribute to a constant efficacy and good physicochemical properties of the sunscreen formulations. Therefore, to choice a right composition is important for optimizing sunscreen formulations. Based on these findings, a desired sunscreen product was obtained. With high SPF of 68.21, good storage stability, and esthetic appearance, it is composed of CG 90 1.50%、Mineral oil 12.00%、Parsol MCX 10.00%、Parsol 1789 5.00%、Oxynex ST 0.50%、GermabenII 0.64%、TEA 0.10%、Carbopol 1342 0.104%、D.W 70.156%。
Databáze: Networked Digital Library of Theses & Dissertations
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