title: Comparative evaluation of the effect of cyclodextrins and pH on aqueous solubility of apigenin.
abstract: The aqueous solubility of a flavonoid, apigenin, was studied in the presence of first generation cyclodextrins (α-CyD, β-CyD, γ-CyD), ionic and nonionic synthetic derivatives of β-CyD, namely SBE-β-CyD, HP-β-CyD and RM-β-CyD at various physiological pH. The order of solubility enhancement was as follows: RM-β-CyD>SBE-β-CyD>γ-CyD>HP-β-CyD>β-CyD>α-CyD. The phase solubility diagrams of HP-β-CyD and SBE-β-CyD indicated Higuchi AL subtype behavior, suggesting 1:1 stoichiometry of the complex. In contrast, AP subtype, so higher order complex formation can be assumed in the case of RM-β-CyD and γ-CyD. The formation of inclusion complexes has been confirmed by absorption and fluorescence spectroscopic measurements. Increased antioxidant activity was observed due to the inclusion complexes. These results prove that synthetic derivatives of β-CyD will be potentially useful excipients in the development of drug delivery systems for healthcare products containing flavonoids.
authors.affiliation: Department of Pharmaceutics, Semmelweis University, Hőgyes E. Street 7-9, H-1092 Budapest, Hungary.
authors.forename: Zsófia Edit
authors.initials: ZE
authors.lastname: Pápay
authors.affiliation: Department of Pharmaceutics, Semmelweis University, Hőgyes E. Street 7-9, H-1092 Budapest, Hungary.
authors.forename: Zita
authors.initials: Z
authors.lastname: Sebestyén
authors.affiliation: Department of Pharmaceutics, Semmelweis University, Hőgyes E. Street 7-9, H-1092 Budapest, Hungary.
authors.forename: Krisztina
authors.initials: K
authors.lastname: Ludányi
authors.affiliation: Department of Pharmaceutics, Semmelweis University, Hőgyes E. Street 7-9, H-1092 Budapest, Hungary.
authors.forename: Nikolett
authors.initials: N
authors.lastname: Kállai
authors.affiliation: Department of Pharmaceutics, Semmelweis University, Hőgyes E. Street 7-9, H-1092 Budapest, Hungary.
authors.forename: Emese
authors.initials: E
authors.lastname: Balogh
authors.affiliation: Department of Plant Anatomy, Institute of Biology, Eötvös University, Pázmány Péter Street 1/C, Budapest, Hungary.
authors.forename: Annamária
authors.initials: A
authors.lastname: Kósa
authors.affiliation: Department of Pharmaceutics, UCL School of Pharmacy, 29-39 Brunswick Square, London WC1N 1AX, United Kingdom.
authors.forename: Satyanarayana
authors.initials: S
authors.lastname: Somavarapu
authors.affiliation: Department of Plant Anatomy, Institute of Biology, Eötvös University, Pázmány Péter Street 1/C, Budapest, Hungary.
authors.forename: Béla
authors.initials: B
authors.lastname: Böddi
authors.affiliation: Department of Pharmaceutics, Semmelweis University, Hőgyes E. Street 7-9, H-1092 Budapest, Hungary. Electronic address: antal.istvan@pharma.semmelweis-univ.hu.
authors.forename: István
authors.initials: I
authors.lastname: Antal
mesh_terms: D047310:Apigenin / Q000032:analysis* / Q000737:chemistry; D002853:Chromatography, Liquid / Q000379:methods; D003505:Cyclodextrins / Q000032:analysis* / Q000737:chemistry; D004353:Drug Evaluation, Preclinical / Q000379:methods; D006863:Hydrogen-Ion Concentration; D012995:Solubility; D053719:Tandem Mass Spectrometry / Q000379:methods; D014867:Water / Q000032:analysis* / Q000737:chemistry
chemical_list: D003505:Cyclodextrins; D014867:Water; D047310:Apigenin
keywords: Antioxidant activity; Apigenin; Cyclodextrins; Phase solubility studies; Solubility improvement