CAS 50-21-5 appears in our catalog under these names: Lactic acid, 1.0N Standardized Solution , Lactic acid, ACS, 85.0-90.0% aq. soln. , DL-Lactic acid, 80-85% aq. soln. . Offered by: Thermo Scientific (Alfa Aesar). Available pack sizes: 500ml, 100g, 500g, 2kg, 1000g, 250g.