Chromatographic determination of active compounds in topical formulations

Abstract

The aim of this study was to develop and validate new methods for the determination of active compounds in topical gels. The method for the determination of nonoxinol-9 and trimecaine hydrochloride in lubricant gel by HPLC with UV detection was described. Separation was carried out using a Discovery ZR-PBD analytical column (150 × 4.6 mm, 5 μm), and a mobile phase composed of a mixture of triethylammonium acetate buffer (pH 9; 50 mM) and methanol (22 : 78, v/v). Determination of terpinen-4-ol in lubricant gel was achieved by GC with a flame ionization detector (FID). An Alltech-AT-624 (0.32 mm ID × 30 m, 1.8 μm film thickness) fused-silicacapillary column and helium as the carrier gas, at a flow rate of 28 cm s⁻¹, were employed. The analysis time was less than 7.5 min for HPLC and 5 min for GC analyses. Both methods were successfully applied to the analysis of pharmaceuticals.