Abstract: A free-flowing, powdery composition contains a lipoic acid component and from 0.1 to 25% by weight of the total composition of a silica-based flow aid having a particle size (×100 value) of <800 ?m.

Abstract: This free-flowing, powdery composition containing ?-lipoic acid (derivatives) is distinguished by comprising, besides the lipoic acid component, from 0.1 to 25% by weight, based on the total weight of the composition, of a hydrophilic or hydrophobic silica-based flow aid which has a particle size (×100 value) of <800 ?m and a tamped density of from 50 to 600 g/l. The lipoic acid component is moreover not confined to the free acid form, but may also be at least partly in the form of its salts. Preferred flow aids are spray-dried precipitated silicas and/or highly dispersed silicas and/or amorphous silica gels. Besides the particle size and the tamped density, the flow aid employed may also be characterized by its specific surface area, which preferably ought to be between 30 and 1000 m2/g, or by the fact that the flow aid brings about a pH of between 3 and 11.5 in a concentration of 5% in aqueous solution.

Abstract: The present invention describes a stable, acidic, aqueous solution of &agr;-lipoic acid or derivatives thereof. A content of the lipoic acid component employed which is above the intrinsic solubility thereof in the aqueous solution is achieved preferably by a production method in which in a first stage a stock solution of the lipoic acid component in water is provided with the aid of a base, then this stock solution is brought where appropriate by dilution and temperature control into the desired concentration range and temperature range, and finally the desired pH of the solution is adjusted by adding an acid. The solution obtained inter alia in this way is, owing to its stable properties, outstandingly suitable for use for pharmaceutical, cosmetic, dietary or else technical purposes, for example for diminishing photochemical effects.

Abstract: Solvent-free &agr;-lipoic acid is produced by dissolving a) the &agr;-lipoic acid to be purified in aqueous alkaline solution, or dissolving the salt thereof in water and adjusting an alkaline pH, b) removing solid impurities present where appropriate from the aqueous solution from stage a), c) adjusting the aqueous solution from stage a) or b) to a pH of from 1.0 to 5.0 with the aid of an acid and d) isolating the precipitated &agr;-lipoic acid by known methods. This results in a solvent-free &agr;-lipoic acid with improved chemical purity.