title: Water determination in drugs containing ascorbic acid.
abstract: A new rapid analytical method was applied for water determination in tablets of vitamin C, Ce De Calcium Veterinary, and C-Tamin-500 containing ascorbic acid and therefore is not amenable for direct Karl Fischer (KF) titration. The method is based on the consecutive titration first of ascorbic acid by a novel reagent and then of water by a conventional KF reagent (KFR) in the same sample and cell with the electrometric "dead-stop" location of the end point in both titrations. The new reagent consists of iodine, potassium iodide, and sodium acetate in nonaqueous medium. Estimated repeatability and accuracy of both water and ascorbic acid determination are satisfactory.
authors.affiliation: National Physical Laboratory of Israel, Givat Ram, Jerusalem, Israel.
authors.forename: F
authors.initials: F
authors.lastname: Sherman
authors.forename: I
authors.initials: I
authors.lastname: Kuselman
mesh_terms: D001205:Ascorbic Acid / Q000032:analysis*; D002626:Chemistry, Pharmaceutical / Q000379:methods*; D013607:Tablets; D013678:Technology, Pharmaceutical; D014867:Water / Q000032:analysis*
chemical_list: D013607:Tablets; D014867:Water; D001205:Ascorbic Acid