... ones in 1957. Now it is extensively and used in pharmacy,daily chemical industries and other industrial fields ... 0Residue on ignition,%≤2.0Heavy metal,ppm≤20Viscosity15-30Assay for carboxylic acid content,%56.0-68.0US Pharmacopoeia( ... (5% neutral solution)Usage93430500-39400Preparation for topical use,gels,emulsion,suspension94040000-60000Preparation for topical use,crystal gels with good ...