G418 Supplier?

[Michael Galperin]

      Hi, geneticin users.
      I am posting this question for a friend who is having a bad luck with
 her attempts to inhibit growth of control CHO cells with G418 (from Sigma).
 Though the chemical is claimed to be have about 66% of the active ingredient,
 it didn't prevent cell growth unless added to 15 mg/ml, making it $1.5/plate.
 Any ideas/suggestions/references  would be welcome.

Michael Y. Galperin                  Bitnet: mygalp01 at ulkyvm
U of L - Microbiology                 Voice: (502) 588-7539
Louisville, KY  40292                   Fax: (502) 588-7531