44 NATURALS TDS10011190
140% 130% 120% 110% 100% 90% 80% 70% 60%
Initial value
washing After
1% PCA Na ■ Without PCA Na ■ n=4
TDS10011200
140% 130% 120% 110% 100% 90%
5 min 10 min 20 min After application 30 min
Initial value
washing After 5 min 10 min 20 min After application
Figure 5: Improvement of skin condition with face mask containing 1% PCA Na. Moisture content of stratum corneum (left) and TEWL (right) From the left panel of Figure 4, PCA Na
shows a higher change in skin capacitance than glycerin, indicating that it has superior moisturizing properties. From the right panel of Figure 4, it was found that PCA Na was absorbed more into the stratum corneum than glycerin. All these effects were PCA concentration
dependent. From the above, PCA Na has moisturizing performance equivalent to or higher than that of glycerin, a typical humectant.
The data presented so far was an
evaluation using a simple aqueous solution of each humectant and measured the moisturizing performance of the humectant itself. However, actual cosmetics are multi- component systems containing many raw materials and such complex systems are required to exhibit sufficient moisturizing effects. The following shows the moisturizing properties when PCA Na is blended into a face mask formulation similar to an actual product. The value after pre-rinsing with water was
taken as the initial value. After that, the face was washed with a commercially available
O O
N H
O Figure 6: Structure of PCA Zn
foam face wash, and after 20 minutes of acclimatization in a constant temperature and humidity room under controlled conditions. A face mask soaked with 10g of internal
solution with/without PCA Na was applied to each side of the face respectively for each face for five minutes. After wiping off the excess liquid, the stratum corneum water content and trans epidermal water loss (TEWL) were measured five to 30 minutes later. As a result, the moisture content of the
stratum corneum, face masks containing 1% PCA Na recovered faster from the decrease in moisture content of the stratum corneum caused by washing with facial cleansers than products without PCA Na. Regarding TEWL, it
0
-0.05 0.1
-0.15 -0.2
-0.25 -0.3
n=22, ** p<0.01 Wilcoxon signed-rank test Control ■ With AJIDEW ZN-100 ■
CONTROL Zn2 2 +
n=4
30 min
was also found that the face mask containing 1% PCA Na quickly lowered TEWL which had increased after washing. Therefore, it was found that PCA Na exhibits moisturizing properties even in a complex formulation system.
Pyrrolidone carboxylic acid zinc salt (PCA Zn) Zinc pyrrolidone carboxylate (trade name AJIDEW™ ZN-100) is a skin conditioning agent obtained by neutralizing pyrrolidone carboxylic acid with zinc. Zinc compounds are generally known to have skin astringent effects and sebum secretion suppressing effects, and PCA Zn can be expected to have similar effects. Figure 7 shows the wrinkle improvement
effect of continuous use of a PCA Zn containing lotion. After washing their faces twice a day (morning and evening), subjects continued to apply the test formulation around their eyes for three months. Photos were taken under normal light
after 15 minutes of acclimatization under constant temperature and humidity conditions (temperature 20°C ± 2°C, relative humidity 50%
** ** ** WITH 0.3% PCA Zn
Initial
4 weeks Figure 7: Improvement of wrinkle grade by PCA Zn PERSONAL CARE June 2024
8 weeks Period Figure 8: Appearance of wrinkle improvement effect by PCA Zn
www.personalcaremagazine.com
12 weeks
Deference of Wrinkle Grade (12 weeks) (Initial)
Water content Comparison to initial value
TEWL Comparison to initial value
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