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acute toxicity: inhalation
Data waiving:
study scientifically not necessary / other information available
Justification for data waiving:
the study does not need to be conducted because exposure of humans via inhalation is not likely taking into account the vapour pressure of the substance and/or the possibility of exposure to aerosols, particles or droplets of an inhalable size
Justification for type of information:
According to Annex VIII, section 8.5.2, column 2 of Regulation No. 1907/2006, testing by the inhalation route is appropriate if exposure of humans via inhalation is likely. In an OECD Guideline 104 study, the vapour pressure of balsalazide acid was found to be 3.80E-05 Pa at 20°C. Based on this result, balsalazide acid is not a volatile substance and hence exposure via inhalation is unlikely. Furthermore, a particle size distribution study showed that 98% of the particles of balsalazide acid were above 250 µm and therefore outside the inhalable range. Inhalation exposure during manufacture of balsalazide acid and its use as an intermediate is unlikely due to the risk mitigation measures in place in the pharmaceutical facility and that all processes are performed in accordance with Good Manufacturing Practices. Therefore, the performance of an acute inhalation study on balsalazide acid is considered scientifically unjustified based on the physico-chemical properties of the substance and the way in which is it is handled in industry as a pharmaceutical intermediate.

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Materials and methods

Results and discussion

Applicant's summary and conclusion