High-performance liquid chromatographic method for the assay of dexamethasone and xylometazoline in nasal drops containing methyl p-hydroxybenzoate.

A rapid and sensitive high-performance liquid chromatographic method has been developed for the determination of dexamethasone sodium phosphate (DSP), xylometazoline hydrochloride (XMC) and methyl p-hydroxybenzoate (MHB). An assay of the compounds has been performed on a HPLC system GBC 1210, at controlled room temperature, on a Nucleosil C8 column (250x3 mm, 5 microm). The mobile phase was acetonitrile-water (35:65, v/v), at a flow-rate of 1 ml min(-1). The parameters for validation such as linearity (r>0.9996), precision (RSD: 0.51-(1.93%), limit of detection and quantification (2.032 x 10(-4) and 4.063 x 10(-4) mg ml(-1) for DSP, 9.7 x 10(-5) and 1.953 x 10(-4) mg ml(-1) for XMC, 1.953 x 10(-4) and 3.096 x 10(-4) mg ml(-1) for MHB) have also been reported. The method was applied to the determination of DSP, XMC and MHB in nasal drops. The statistical parameters were found to be satisfactory, with recovery values ranging from 98.69 to 101.60% (RSD: 0.32-1.03%). The method is simple and accurate and therefore suitable for the simultaneous determination of these compounds in dosage form.

Simultaneous assay of ephedrine hydrochloride, theophylline, papaverine hydrochloride and hydroxyzine hydrochloride in tablets using RP-LC.

The analytical problem was to control the quality of imported antiasthmatic tablets containing ephedrine hydrochloride, theophylline, papaverine hydrochloride and hydroxyzine hydrochloride. The aim of the analytical method for the assay was to separate, identify and quantify all compounds, at the same time. A gradient capable RP-LC system was used, using a commercially packed Nucleosil C18 column connected to a dual channel variable, programmable wavelength detector. The analysis was performed in the gradient program of increasing concentration of acetonitrile in water. The influence of pH of the mobile phase was established. The proposed method is reliable, reproducible, easy to perform and satisfies the aim.