Benzocaine is a local anaesthetic which acts by preventing the generation and transmission of impulses along nerve fibers and at nerve endings. Depolarisation and ion-exchange are inhibited. In general, loss of pain occurs before loss of sensory, autonomic and motor functions. Oxytetracycline binds reversibly to the 30S and possibly 50S ribosomal subunits, thus inhibiting bacterial protein synthesis and arresting cell growth. It is active against a wide range of gram-positive and gram-negative organisms. Polymyxin B disrupts the bacterial cytoplasmic membrane of mostly gm-ve organisms allowing leakage of intracellular constituents by binding to membrane phospholipids.