The present invention provides topical compositions, methods of preparation, and methods of treatment for onychomychosis. In certain specific embodiments, the invention provides an anti-fungal pharmaceutical composition for topical application comprising an anti-fungal agent, a zwitterionic surfactant or charged derivative thereof; a carboxylic acid, a lower alcohol, and water. The acid is selected from a short-chain hydroxy acid, a short-chain fatty acid, and a mixture thereof. In certain other specific embodiments, the invention provides an anti-fungal pharmaceutical composition for topical application comprising an anti-fungal agent, a quarternary amino acid, a keratolytic agent; a lower alcohol; and water. In certain embodiments, the keratolytic agent is urea, ammonium thioglycolate, or a mixture thereof.