Validation of an isocratic LC method for determination of quercetin and methylquercetin in topical nanoemulsions

摘要

The aim of this study was to validate an isocratic LC method for the quantification of either quercetin (Q) or methylquercetin (MQ) incorporated in topical nanoemulsions. The analyses were performed at room temperature on a reversed-phase C_18 column using a mobile phase composed of methanol/water (70:30, v/v) and trifluoracetic acid 0.1percent at 0.8m Lmin~(-1). The detection was carried out on a UV detector at 368 or 354nm for Q and MQ, respectively. The linearity, in the range of 0.15-1.5 mug/m L, presented a determination coefficient (r~2) higher than 0.99, calculated by the least square method for both flavonoids. No interferences from the excipients (egg-lecithin or octyldodecanol) were detected. The R.S.D. values for intra- and inter-day precision experiments were lower than 2percent for both flavonoids. The recovery ranged from 98.9percent to 103.46percent for Q and from 98.9percent to 102.92percent for MQ.