Validation of an LC method to determine skin retention profile of genistein from nanoemulsions incorporated in hydrogels.
Recent studies have shown the effect of soy isoflavones in preventing skin photoaging and photocarcinogenesis, especially for genistein (GEN). Nanoemulsions have been proposed as a delivery system for GEN administration due to the low water solubility of this isoflavone. This article describes the validation of an isocratic liquid chromatography method to determine GEN in porcine ear skin layers from nanoemulsions before and after incorporation into hydrogels. The analyses are performed on a reversed-phase C18 column using a mobile phase composed of methanol-water (70:30, v/v) under acid conditions (at pH 3.0) and UV detection at 270 nm. The method is linear in the range of 0.1-10 µg/mL (r(2) > 0.999) in the presence of skin extracts. The low limit of quantitation is estimated as 0.1 µg/mL. No interferences from formulation excipients or skin layer compounds are detected. The RSD values for intra- and inter-day precision are lower than 15%. Recovery ranged from approximately 90% to 110%. The method is applied to estimate GEN retention in the skin from formulations using Franz diffusion cells. The highest amount of GEN is detected in the epidermis (185 µg/cm(2)). In conclusion, the method proved to be specific, precise, and accurate in determining GEN amounts from formulations in skin retention studies.
Universidade Federal do Rio Grande do Sul, Faculdade de Farmácia, Programa de Pós-Graduação em Ciências Farmacêuticas, Porto Alegre, RS, Brazil.
Bethânia Andrade
BA
de Vargas
Débora Fretes
DF
Argenta
Greice
G
Borghetti
Leticia Scherer
LS
Koester
Valquiria Linck
VL
Bassani
Helder Ferreira
HF
Teixeira
D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D004655:Emulsions; D019833:Genistein / Q000378:metabolism*; D020100:Hydrogels; D049329:Nanostructures; D015203:Reproducibility of Results; D012867:Skin / Q000378:metabolism*; D013056:Spectrophotometry, Ultraviolet; D013552:Swine
D004655:Emulsions; D020100:Hydrogels; D019833:Genistein