A liquid chromatographic method for the determination of tolnaftate in pharmaceutical formulations

A simple LC method was developed and validated for the analysis of tolnaftate in various pharmaceutical formulations. This method did not require any complex sample extraction procedure. The chromatographic separation was achieved on a reversed-phase, C₁₈ column with UV detection at 258 nm. This isocratic system was operated at ambient temperature and required 9 min of chromatographic time. The mobile phase consisted of methanol-aqueous potassium dihydrogen phosphate solution (80:20, v/v) at a flow rate of 1.5 ml min^-1. Standard curves were linear over the concentration range of 1.0-51.0 μg ml^-1. Within-day and between-day relative standard deviation values ranged from 0.7 to 2.9% and from 1.3 to 3.4%, respectively. This method was used to quantify tolnaftate in microcapsule, microsphere, cream, powder, liquid, liquid aerosol and powder aerosol formulations. This method was also used to study the stability of tolnaftate in solution during its extraction from microcapsule formulations.