The present invention is related to pharmaceutical compositions that include a phosphonium antimicrobial agent. In a preferred embodiment, the present invention relates to an otic, nasal or ophthalmic composition (e.g., an aqueous ophthalmic solution) that includes a phosphonium salt compound as an antimicrobial agent. The compositions typically possess sufficient antimicrobial activity to satisfy USP preservative efficacy requirements and/or similar preservative standards (e.g., EP and JP).
