The limit applied to the originator solvent is such that the class 1 solvent will be present in the
active substance at levels below the limits set out in the guideline, taking into account the
maximum likely level of contamination of the class 1 solvent. The volatility of both solvents in
the drying processes must be taken into account when applying this argument;
• It is demonstrated with a validated method that the class 1 solvent is not more than 30 % of the
specified limit, in a suitable intermediate or in the final active substance. Supporting data should
be presented on 6 consecutive pilot scale batches or 3 consecutive industrial scale batches;
• The specification for the originator solvent used includes a routinely performed test and limit for
the class 1 solvent.