PROBLEM TO BE SOLVED: To provide a method for producing a water-insoluble powder dispersion, which retains the characteristics original to an anionic polysaccharide which is the raw material, has high safety because there is no need of using a chemical cross-linking agent during production, and is useful as a base material for medical use, capable of being uniformly distrained to an affected part, and of cosmetics, etc.SOLUTION: Provided is a method for producing a water-insoluble powder dispersion, comprising: a step where raw material powder made of a polyanionic polysaccharide is treated with a treatment liquid containing an acid anhydride, and the raw material powder is water-insolubilized to obtain a water-insoluble powder； and the water-insoluble powder is pulverized into an average particle diameter of 1.5 μm or less and is dispersed into water-based solvent to obtain a water-insoluble powder dispersion.SELECTED DRAWING: None【課題】原料であるポリアニオン性多糖類本来の特性が保持されているとともに、製造時に化学架橋剤を用いる必要がないため安全性が高く、患部に均等に留置させることが可能な医療用・美容材料等の基材として有用な水不溶性粉末分散液の製造方法を提供する。【解決手段】ポリアニオン性多糖類の水溶性塩からなる原料粉末を、酸無水物を含む処理液で処理し、原料粉末を水不溶化させて水不溶性粉末を得る工程と、水不溶性粉末を平均粒子径１．５μｍ以下に粉砕し、水系溶媒中に分散させて水不溶性粉末分散液を得る工程と、を有する水不溶性粉末分散液の製造方法である。【選択図】なし
