The high-performance thin-layer chromatographic determination of dexamethasone and xylometazoline in nasal drops containing different preservatives

Abstract

A simple and reliable HPTLC method has been developed and validated for the determination of dexamethasone (as the sodium phosphate salt) and xylometazoline (as the chloride). Assay of the compounds was performed on silica gel HPTLC plates with spherical particles by development with the mobile phase ethyl acetate-acetonitrile-diethylamine-water, 3 + 3 + 1 + 1 (v/v). A TLC scanner set at lambda = 240 nm was used for direct evaluation of chromatograms in reflectance/absorbance mode. The validation data linearity (R > 0.996), precision (RSD = 1.67-2.77%), accuracy (recovery = 95.95-100.69%) and LOD and LOQ (ng levels) were determined and found to be satisfactory. Assay of dexamethasone and xylometazoline in nasal drops was performed simultaneously with assay of preservatives such as methyl para-hydroxybenzoate. The effect of the most commonly used preservative, benzalkonium chloride on the concentrations of active substances was investigated; it was found that this compound led to a significant reduction of the dexamethasone sodium phosphate content of nasal drops.