Daidzein/cyclodextrin/hydrophilic polymer ternary systems.
OBJECTIVE
To evaluate the effect of different cyclodextrins (β-cyclodextrin [β-CD], methyl-β-cyclodextrin [Mβ-CD], or hydroxypropyl-β-cyclodextrin [HPβ-CD]) and/or hydrophilic polymers (carboxymethylcellulose, hydroxypropylmethylcellulose [HPMC], polyethyleneglycol, or polyvinylpyrrolidone [PVP]) on daidzein solubility in water.


METHODS
The corresponding associations were characterized in aqueous media using phase-solubility studies. The morphology of daidzein/cyclodextrin freeze-dried complexes was characterized using scanning electron microscopy, and their spatial configuration was proposed by means of nuclear magnetic resonance spectroscopy.


CONCLUSIONS
In the presence of 6 mM of cyclodextrins, the solubility of daidzein in water was significantly enhanced: 5.7-fold (β-CD), 7.2-fold (Mβ-CD), and 9.4-fold (HPβ-CD). The analysis of the three solid complexes proved that the formation of inclusion complexes occurred through the insertion of the B and C rings of daidzein molecule into the cyclodextrins cavity. The association of daidzein/cyclodextrin complexes to the hydrophilic polymers HPMC or PVP (1%, w/w) was able to improve the solubility of daidzein even further.


CONCLUSIONS
The highest solubilizing effect was obtained for daidzein/HPβ-CD/PVP ternary system (12.7-fold).
Programa de Pós-Graduação em Ciências Farmacêuticas, Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil. greicefarm@yahoo.com.br
Greice Stefani
GS
Borghetti
Angela Pinheiro
AP
Pinto
Ivana Silva
IS
Lula
Rubén Dario
RD
Sinisterra
Helder Ferreira
HF
Teixeira
Valquiria Linck
VL
Bassani
D002626:Chemistry, Pharmaceutical; D003505:Cyclodextrins / Q000737:chemistry*; D057927:Hydrophobic and Hydrophilic Interactions; D007529:Isoflavones / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D048789:Phytoestrogens / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D012995:Solubility; D014867:Water / Q000737:chemistry
D003505:Cyclodextrins; D007529:Isoflavones; D048789:Phytoestrogens; D011108:Polymers; D014867:Water; C004742:daidzein