Difference: the component of cefaclor dispersible tablets is cefaclor, and its chemical name is (6R, 7R)-7-[(R)-2- amino -2- phenylacetylamino ]-3- chloro -8- oxo -5- thio-1- azabicyclo [4.2.0] octyl-. Molecular formula: C 15H 14ClN3O4S? 6? The component of 1H2O cefpropylene tablets is cefpropylene, and its chemical name is (6R, 7R)-7-[(R)-2- amino -2- (p-hydroxyphenyl) acetamido ]-8- oxo -3- propylene -5- thio-1- azabicyclo-