UA48969C2 - Stain compositions in vivo, method of their production, method of use for identification of displastic tissue, hplc method of analysis - Google Patents

Abstract

The N-demethylation and N,N-demethylation derivatives of the two conformational isomers toluidine blue О ("TBO") have been isolated, identified and prepared. An in vivo biological stain composition includes the conformational isomers of TBO and these N- and N,N-demethylation derivatives. The ratio of these isomers to these demethylation derivatives is at least 6:1. An improved method for detecting displastic oral tissue includes application of such TBO products, in a liquid carrier, to oral tissue. A process for preparing TBO products includes (1) oxidizing N,N-dimethyl--phenylenediamine to form an intermediate 2-amino-5-dimethylaminophenyl thiosulfonic acid, (2) oxidizing this intermediate and condensing the oxidizate with -toluidine, forming indamine thiosulfonic acid and (3) further oxidizing the indamine intermediate to form a TBO-containing reaction product, which is precipitated from the reaction mixture as a complex, from which the final TBO product is separated. The complexing agent is added to the reaction mixture at least before the final oxidation stеp, preferably before the second oxidation step. An HPLC method for characterizing TBO products containing the conformational isomers of TBO and their N-and N,N-demethylation derivatives. A mobile phase comprises an aqueous solution of an organic acid compound.