title: Development and validation of a stability indicative HPLC-PDA method for kaurenoic acid in spray dried extracts of Sphagneticola trilobata (L.) Pruski, Asteraceae.
abstract: A gradient stability indicative HPLC-UV method was developed and validated for assay of the marker kaurenoic acid (KA) in spray dried extract of Sphagneticola trilobata (L.) Pruski. The marker, and another unidentified polar component, were separated on a Luna Phenomenex C(18) column (250×4.6 mm, 5 μm) with mobile phase composed of acetonitrile:acidified water pH 3.0 with phosphoric acid, in a gradient run of 40 min; at a flow rate of 1.0 mL min(-1), 35 °C, using wavelengths of 210 and 338 nm. The method was linear over a KA concentration range of 4.5-30.0 μg mL(-1), without interference of the herbal matrix on the linearity of the method. The RSD% values for the intra- and inter-day precision studies were <2.0 and <8.0% for inter-laboratorial study. The method showed excellent KA recovery (99.0%). The LOQ value was found to be 1.13 μg mL(-1) and the method proved to be robust for small, deliberate changes in temperature and pH of the mobile phase with RSD%<2.5% for the KA assay. A forced degradation study of S. trilobata dried extract was conducted under conditions of visible light (1.200.000 l×h(-1)) and UV (200 Whm(-2)) irradiation, acid (0.5 mol L(-1) HCl, 30 min), basic (1 mol L(-1) NaOH, 2 h) and oxidative (30% H(2)O(2), 4h) hydrolysis, in order to develop a gradient stability-indicating LC-UV method for KA quantification, the selected marker, and also to detect the major polar components of the extract, under investigation. The KA contents remaining after these stress conditions were 72.3, 70.0, 97.6, 65.8 and 87.0%, respectively. The alkaline conditions resulted in higher degradation for the unknown polar components of the extract, without interference of supplementary peaks at the retention time of the KA. This method can be used for the KA assay and qualitative analysis of polar components in stability study of spray dried extracts of S. trilobata, for subsequent use in the quality control of dosage forms.
authors.affiliation: Núcleo de Investigações Químico-Farmacêuticas (Niqfar), Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade do Vale do Itajaí (UNIVALI), caixa postal 360, CEP 88302-202 Itajaí-SC, Brazil; Laboratório Farmacêutico Elofar, Florianópolis-SC, Brazil.
authors.forename: Giovana
authors.initials: G
authors.lastname: Fucina
authors.forename: Luciana Catia
authors.initials: LC
authors.lastname: Block
authors.forename: Thaisa
authors.initials: T
authors.lastname: Baccarin
authors.forename: Thiago Ruiz Gutierrez
authors.initials: TR
authors.lastname: Ribeiro
authors.forename: Nara Lins Meira
authors.initials: NL
authors.lastname: Quintão
authors.forename: Valdir Cechinel
authors.initials: VC
authors.lastname: Filho
authors.forename: Ruth Meri Lucinda
authors.initials: RM
authors.lastname: Silva
authors.forename: Tania Mari Bellé
authors.initials: TM
authors.lastname: Bresolin
mesh_terms: D019659:Asteraceae / Q000737:chemistry*; D002138:Calibration; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D004224:Diterpenes / Q000032:analysis*; D057230:Limit of Detection; D010936:Plant Extracts / Q000737:chemistry*; D015203:Reproducibility of Results; D013056:Spectrophotometry, Ultraviolet
chemical_list: D004224:Diterpenes; D010936:Plant Extracts; C051436:kaurenoic acid