Silicon

Additional toxicological data

Administrative data

Endpoint:

additional toxicological information

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: well documented study, meeting basic scientific standards

Data source

Reference

Reference Type:

publication

Title:

Influence of particle dose on the cytotoxicity of hamster and rat pulmonary alveolar macrophage in vitro.

Author:

Warshawsky, D., R. Reilman, et al.

Year:

1994

Bibliographic source:

J Toxicol Environ Health.42(4): 407-21.

Materials and methods

Type of study / information:

in vitro study

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

The cytotoxicity of the substances to hamster and rat alveolar macrophages (AM) in vitro was measured at 0.0-0.5 mg/10-6 cells at 24 and 48 h using dye exclusion procedures.

GLP compliance:

no

Test material

Test material information

Constituent 1

Reference substance name:

gelled silica

IUPAC Name:

gelled silica

Constituent 2

Reference substance name:

precipitated silica

EC Number:

927-048-3

IUPAC Name:

precipitated silica

Constituent 3

Reference substance name:

fumed silica

IUPAC Name:

fumed silica

Constituent 4

Reference substance name:

crystalline silica

IUPAC Name:

crystalline silica

Details on test material:

- crystalline silica: Min-U-Sil
- fumed silica: Cab-O-Sil® M-5
- The medium diameter for amorphous silica was <0.38 μm and for crystalline 0.83 μm. The surface areas for the amorphous silicas ranged from 235 to 125 m2/g (order: gelled > fumed > precipitated) and for crystalline silica 4.3 m2/g.

Results and discussion

Any other information on results incl. tables

With gelled silica the viability of the hamster alveolar macrophages decreased to 27% at 0.05 mg/ml and to zero at 0.1 mg/ml t 24 h. At doses of 0.05 and 0.1 mg/ml of crystalline, precipitated or fumed silica, the percent viability decreased significantly to 76-67% and 51-42%, respectively, and to zero at 0.5 mg/ml. The count of macrophages viable at 24 h decreased further at 48 h compared with the control value. The order of toxicities was: gelled > precipitated, fumed, and crystalline.

Applicant's summary and conclusion

Conclusions:

The order of cytotoxicity was: gelled silica> precipitated, fumed, and crystalline silica.

Executive summary:

Warshawsky et al. (1994) studied crystalline (Min-U-Sil), gelled, precipitated and fumed (pyrogenic, Cab-O-Sil® M-5) silicas with alveolar macrophages. The cytotoxicity of the silicas to hamster and rat alveolar macrophages (AM) in vitro was measured at 0.0-0.5 mg/10^-6cells at 24 and 48 hours using dye exclusion procedures. The medium diameter for amorphous silica was <0.38 μm and for crystalline 0.83 μm. The surface areas for the amorphous silicas ranged from 235 to 125 m²/g (order: gelled > fumed > precipitated) and for crystalline silica 4.3 m²/g.

With gelled silica, the viability of the hamster alveolar macrophages decreased to 27% at 0.05 mg/ml and to zero at 0.1 mg/ml t 24 hours. At doses of 0.05 and 0.1 mg/ml of crystalline, precipitated or fumed silica, the percent viability decreased significantly to 76-67% and 51-42%, respectively, and to zero at 0.5 mg/ml. The count of macrophages viable at 24 hours decreased further at 48 hours compared with the control value. The order of toxicities was: gelled > precipitated, fumed, and crystalline.