Abstract: 1. A method of producing flowable R,S-thioctic acid, R,S-thioctic acid and its use.2.1. Known methods of preparing flowable thioctic acid which can be galenically further processed by pressing to highly-concentrated, solid presentations with active-substance contents of more than 200 mg pure substance require the mixing of the thioctic-acid forms of different origins and/or a spraying on of galenic adjuvants from aqueous solution and a subsequent grinding process in order to arrive at a pressable granulate.2.2.

Abstract: L-amino acids present in cleavage solutions obtained in the acylase-catalyzed cleavage of N-acetyl-D,L-amino acids are isolated by use of a strongly acidic ion exchanger in H+ form. First, the mother liquor from a previous treatment cycle is fed to the ion exchanger, and then the cleavage solution and finally the wash water and the discharge from the ion exchanger which is pH-controlled is analyzed into an "effluent water fraction", an "N-acetyl-D-amino acid fraction" and an "L-amino acid fraction". The last fraction is adjusted by addition of fresh cleavage solution to a pH of between 4.0 and 6.0, and from the mixture which is thus obtained the L-amino acid is isolated by crystallization. The mother liquor which is obtained is recycled back into a subsequent treatment cycle.