Class 1 solvents include benzene; carbon tetrachloride; 1,2-dichloroethane; 1,1-dichloroethene; and 1,1,1-trichloroethane.
The American Herbal Products Association (AHPA; Silver Spring, MD) has revised its guidance policy on residual solvents in herbal extracts, now specifically prohibiting the use of Class 1 solvents. The association also amended its policy concerning the use of acetic acid when it is present in liquid extracts formulated to contain vinegar or acetic acid.
The amended guidance policy now states that Class 1 solvents “are not appropriate for use, and should not be used, in the manufacture of herbal extracts.” The original version did include limits set by the International Conference on Harmonization (ICH) for Class 2 and Class 3 solvents for herbal extracts.
According to ICH, Class 1 solvents include benzene; carbon tetrachloride; 1,2-dichloroethane; 1,1-dichloroethene; and 1,1,1-trichloroethane.
“The previous AHPA policy did not explicitly exclude Class 1 solvents, as ICH makes exemptions for their use in drug manufacture when no other solvents can be used,” stated Steven Dentali, PhD, AHPA’s chief science officer. “AHPA’s Standards Committee, which recommended the new policy to the board, wanted to make it clear that these solvents have no place in the manufacture of herbal extracts due to their unacceptable toxicity or status as an environmental hazard.”
Regarding acetic acid, Dentali stated that AHPA’s Standards Committee “also recognized that some liquid extracts should have an exemption for acetic acid residues when they are formulated with acetic acid or vinegar-which contains acetic acid-in the same way that the earlier guidance policy exempted residual ethanol when it is used as a component in the manufacture of liquid extracts.”
See the revised guidance policy here.