Interlaboratory validation of the in vitro eye irritation tests for cosmetic ingredients (9). Evaluation of cytotoxicity test on HeLa cells.
The cytotoxicity test using MTT on HeLa cells (HeLa-MTT) was evaluated as an alternative method to the Draize eye irritation test (Draize test) by six to eight laboratories. The 50% inhibition concentration (EC(50)) for MTT reduction was calculated. A total of thirty-nine test chemicals were examined. The average interlaboratory coefficient of variation (CV) of the present assay was 25%. Comparison of the in vitro test results with those of the Draize test revealed a correlation coefficient of -0.799 between the log(EC(50)) value and the maximum average total score (MAS) for a 10% solution or suspension. The following characteristics of HeLa-MTT have become apparent through this validation: (1) HeLa-MTT could be applied to all substances including water-insoluble substances, esters, a colour additive, and a substance which is known to directly reduce MTT; (2) there is good interlaboratory reproducibility and strong correlation between HeLa-MTT and Draize MAS; (3) results for strong acids, alkanolamines and alcohols (lower mono-ol) clearly deviate from other samples with respect to the correlation between HeLa-MTT and Draize MAS. These results suggest that HeLa-MTT may be useful for predicting the Draize MAS if definite criteria can be established for applicable compounds.
Chiba
K
K
Japan Cosmetic Industry Association, Hatsumei Bldg, 9-14, Toranomon 2-chome, Minato-ku, Tokyo 105Japan; Yakult Central Institute for Microbiological Research, 1796 Yaho, Kunitachi-shi, Tokyo 186-8650Japan.
Makino
I
I
Ohuchi
J
J
Kasai
Y
Y
Kakishima
H
H
Tsukumo
K
K
Uchiyama
T
T
Miyai
E
E
Akiyama
J
J
Okamoto
Y
Y
Kojima
H
H
Okumura
H
H
Tsurumi
Y
Y
Usami
M
M
Katoh
K
K
Sugiura
S
S
Kurishita
A
A
Sunouchi
M
M
Miyajima
A
A
Hayashi
M
M
Ohno
Y
Y