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Additional toxicological data

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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

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Type:
Constituent
Type:
Constituent
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.