OTICUM

Polymixin B is bactericidal against a wide range of gram negative bacilli. It exerts a bactericidal effect by binding to acid phospholipids in the cell wall and membranes of the bacterium, thereby rendering ineffective the osmotic barrier normally provided by the cell membrane.

Neomycin is an aminoglycoside antibiotic and acts by binding to polysomes, inhibiting protein synthesis and generating errors in the transcription of the genetic code.

Betamethasone is a glucocorticoid which is about eight to ten times as active as prednisolone on a weight-for-weight basis. Betamethasone has anti-inflammatory, antipruritic, and vasoconstrictive properties.

Lidocaine, like other local anaesthetics, causes a reversible blockade of impulse propagation along nerve fibres by preventing the inward movement of sodium ions through the nerve membrane. Local anaesthetics of the amide-type are thought to act within the sodium channels of the nerve membrane.