Lithium bromide

Dermal absorption

Administrative data

Endpoint:

dermal absorption, other

Type of information:

other: expert statement

Adequacy of study:

key study

Study period:

2013

Reliability:

1 (reliable without restriction)

Data source

Reference

Reference Type:

other: expert statement

Title:

Unnamed

Year:

2013

Report date:

2013

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Expert statement

Test material

Test material information

Constituent 1

Reference substance name:

Lithium bromide

EC Number:

231-439-8

EC Name:

Lithium bromide

Cas Number:

7550-35-8

Molecular formula:

BrLi

IUPAC Name:

lithium bromide

Applicant's summary and conclusion

Conclusions:

The absorption of lithium bromide through skin is considered to be very poor. 10 % absorption was used for DNEL deduction representing a worst case.

Executive summary:

Upon contact with the skin, a compound penetrates into the dead keratinocytes (stratum corneum) and may subsequently reach the viable epidermis, the dermis and the vascular network. During the absorption process, the compound may be subject to biotransformation. The stratum corneum provides its greatest barrier function against hydrophilic compounds, whereas the viable epidermis is most resistant to highly lipophilic compounds.

Due to the physico-chemical characteristics of LiBr together with the known barrier function of the stratum corneum against the respective ions, dermal absorption can practically be excluded. Indeed, lithium bromide is a skin irritant (it is known to be a hygroscopic substance), thus, possible damage to the skin surface may occur and enhance penetration. Nevertheless, such situations can be excluded using non-irritating concentrations, short exposure time or gloves. Lithium bromide is available only to worker in industrial use with applied RMM.

Moreover, LD50 value of > 2000 mg/kg bw obtained in an acute dermal study with lithium bromide support the conclusion of a very limited absorption of lithium bromide through the skin. On the other hand lithium bromide has been identified as a skin sensitizer. Thus, some uptake must have occurred although it is supposed to be a very small fraction of the applied dose.

Regarding lithium ion, a study showed no significant elevation of lithium serum in 53 healthy volunteers spending 20 minutes/day, 4 days/week for two consecutive weeks in a spa with a concentration of approximately 40 ppm (mg/L) lithium (generated from lithium hypochlorite) as compared with unexposed controls. Thus, the authors concluded that absorption of lithium through the skin is considered to be very poor.

In conclusion, the absorption of lithium bromide through the skin is considered to be very poor in case of solutions (not-irritating) and in case of the substance in its solid form (hygroscopic, irritating) when RMM are applied. Thus, upon dermal contact, the bioavailability of lithium bromide is expected to be very low. For DNEL derivation, 10 % absorption was used representing a worst case.