A rapid HPLC method for the quantification of tyrothricin, menthol, and benzocaine in pharmaceutical formulations

A rapid, sensitive, and accurate reversed-phase HPLC method has been developed for the analysis and quantification of pharmaceutical formulations containing tyrothricin (1), an antibiotic used in antiseptic buccal compressed tablets for local application. The assay has been carried out under isocratic conditions, using a stationary phase of alumina particles coated with polybutadiene and an alkaline mobile phase (pH = 8.2). No HPLC method was reported for the analysis of 1. So, this new technique is an alternative to the slow and tedious microbiological methods. On the other hand, it allows the simultaneous quantification of 1, benzocaine (2), and menthol (3), an aromatic compound not currently analyzed by liquid chromatography.