Basf Aktiengesellschaft

Volker Buehler

Axel Sanner

Sven Grabowski

Robert Heinz

Hermann Petersen

Friedbert Hofmann

A process for preparing a free-flowing redispersible powder composed of a vinyl-pyrrolidone/vinyl acetate copolymer containing 15-40% by weight of vinylpyrrolidone units wherein the mixture of the monomers is copolymerized in organic solution, the resulting solution is, after addition of a surfactant, subjected to replacement of the solvent by water, and the resulting dispersion is spray- or freeze-dried, and the use of the redispersible powder for producing paints and coating compositions, glues and adhesives and, in particular, the matrix and/or coating of solid slow-release pharma-ceutical forms and of hair-spray formulations are described.

Redispersible powder composed of n-vinylpyrrolidone/vinyl acetate

Riboflavin granules contain no inactive ingredient and have a mean particle diameter of from 50 to 1,000 .mu.m are produced as described and used for preparing drugs and human and animal foods.

Riboflavin granules containing no inactive ingredient

Ascorbic acid granules for direct tableting are prepared by the compacting method, wherein the ascorbic acid in the form of crystals or crystal fragments, of which not more than 40% by weight have a longest particle diameter of less than 50 .mu.m and not more than 15% by weight have a longest particle diameter greater than 500 .mu.m, and as a mixture with from 0.8 to 8% by weight of soluble polyvinylpyrrolidone having a water content of from 0.3 to 5% is compacted in a conventional manner, and the product is comminuted.

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Wachenheim, Germany

Volker Buehler