Limit for Benzene in Raw materials

[kalidassa]

Dear all how much specification limit we can keep for Benzene content in the raw material (Methanol, Toluene, Acetone, Ethanol, Xylene and Chlorobenzene). We are following 50 ppm limit for all is this correct are want to change the limits further low, can any one help me.

[krickos]

Guessing you talk about raw materials for drug substances/APIs given your other thread. In that thread I gave you a guideline that address this topic in part.
viewtopic.php?f=2&t=19151

Your approch is sound, seen similar by others, but still may have to be followed be a justification based on process that benzene may not me accumalated. Still it raises some issue, for some solvents benzene is a known/likely by product (like toluene), but just as you do not have to add benzene on API spec if benzene is not used in process or generated as biproduct, why should you add it to a specification on a raw material if it simply can not be present?

So just like different API manufacturers of the same API can have different solvents in process and thus different residual solvents specification, the same thinking may be applied of process solvents or synthetic raw materials for that matter.

[kalidassa]

Thank You Mr.Krickos actually what is the problem in our side is we are using commercial hexane for in our process we are having method for testing the content of benzene in the Raw materials also with specification 50 ppm, this test we are doing for safe purpose, but a particular commercial grade hexane contains mote than 100 ppm Benzene, hence we have stooped buying the hexane from the particular vendor, now the problem is we are using the hexane in different steps for different APIs. If u have any reference for the specification for any raw materials with Benzene specification can you share the specification limit with me which you are following in your practice.