preparation of zinc citrate and oral hygiene compositions containing zinc citrate

摘要

A method of preparing a zinc citrate-containing oral care composition, the method comprising: (a) adding zinc oxide to a solution of citric acid in a solvent to form a suspension; (b) agitating the suspension until a clear solution is obtained; and (c) adding an additional oral care ingredient to the solution obtained in (b). Also, a method of preparing a zinc citrate-containing oral care composition, the method comprising: (a) adding citric acid to a suspension of zinc oxide in a solvent; (b) agitating the suspension until a clear solution is obtained; and (c) adding an additional oral care ingredient to the solution obtained in (b). In both methods, steps (a) and (b) are carried out at a temperature of from 10° C. to 50° C. and the molar ratio of zinc oxide to citric acid in step (a) is about 3:2.