Eye Irritation Test of DCR516 - A Natural Cosmetic Ingredient For Sensitive Skin

3月 17, 2021Cosmetic ingredients

DCR 516, as a natural cosmetics ingredient for sensitive skin, can relieve skin inflammation. This test adopts improved CAMVA (Chorioallantoic Membrane Vascular Assay) method to prove there is no eye irritation when DCR516 is used in vitro. The test is carried out white leghorn chicken.

1. DCR 516 Result Observation

The CAMVA stimulus response includes ghosting, congestion, bleeding, etc. The phenomena and stimulus scores are shown in table 1.

Scores	Cardiovascular Effects	Observation and Description
0	Normal	No reaction observed. CAM is normal.
1	Ghosting	Vessels are white, without blood.
2	Congestion	Congestion. CAM is small. Blood flow is accelerated.
3	Slight bleeding	Intra-ring bleeding point coverage is less than 25%
4	Mild bleeding	Intra-ring bleeding point coverage is between 25-50%.
5	Moderate bleeding	Massive bleeding in the ring. The bleeding in a small area covers 50-75%.
6	Sever bleeding	Intra-ring bleeding point is more than 75%, dark scabs may form.

2. DCR 516 Result Evaluation

According to the scores in above Table 1, choose 10 valid chicken embryos for each sample, record irritation score of the sample. Then calculate average value, and get the average stimulation score (AS) of the sample.

AS=(n₁+2n₂+3n₃+4n₄+5n₅+6n₆) /n

n₁、n₂ …… n₆ is the number of chicken embryos corresponding to the score, and n is the total number of chicken embryos.

The corresponding relationship between AS value and eye irritation of the sample is shown in table 2. The table data shows that the higher AS value is, the more irritant the eye is.

Irritation Score	Irritation Level
0≤AS＜0.5	Non-irritant
0.5≤AS＜1.5	Slight irritation
1.5≤AS＜3.5	Mild irritation
3.5≤AS＜5.0	Moderate irritation
5.0≤AS≤6.0	Severe irritation/corrosivity

3. DCR516 Test Result

The following table reveals when AS value is 0 and the concentration of DCR 516 in vitro is 1.0%, no eye irritation can be seen. Thus natural cosmetic raw material DCR 516 for sensitive skin is effective within the concentration of 1.0%.

DCR 516 test result

Table 3. Sample CAMVA test Observation Score

4. DCR516 Test Conclusion

According to the chicken embryo allantoic membrane experiment, we can conclude that natural cosmetics raw material DCR 516 for sensitive skin can not cause irritatant or allergy symptoms at the concentration of 1% in vitro eye irritation test.