Cephaloridine (or<unk>  is a first generation semisynthetic derivative of cephalosporin C. It is unique among cephalosporins in that it exists as a zwitterion.
Cefaloridine
Cefazolin sodium
Meropenem
Cefepime
Cefotaxime sodium
Tazobactam
Aztreonam 
Ampicillin-Sulbactam