Spectrophotometric and electrochemical study of the inclusion complex between beta-cyclodextrin and furnidipine.
Inclusion complexation between furnidipine (2,6-dimethyl-4-(2-nitrophenyl)-1,4-dihydropyridine-3,5-dicarboxylic acid 3-tetrahydrofurfuryl 5-methyl diester), a calcium-channel antagonist, and beta-cyclodextrin (beta-CyD) was studied in aqueous solution by using both spectrophotometric and electrochemical measurements. The phase solubility profile was classified as A(L)-type, indicating the formation of 1:1 stoichiometric inclusion complex of furnidipine with beta-CyD. Based on the spectrophotometric absorbance's variations, a formation constant value, K(f), of 156 M(-1) was determined. Electrochemical measurements using chronocoulometric experiments were used for the determination of the diffusion coefficients. In absence of beta-CyD, a diffusion coefficient value of 4.32 x 10(-6) cm2 s(-1) was obtained for furnidipine. The addition of beta-CyD produced a decrease of 30% for the diffusion coefficient. Formation of inclusion complexes of furnidipine with beta-CyD was proved to increase more than three times the solubility of furnidipine.
Yáñez
C
C
Bioelectrochemistry Laboratory, Chemical and Pharmaceutical Sciences Faculty, University of Chile, P.O. Box 233, Santiago 1, Chile.
Salazar
R
R
Núñez-Vergara
L J
LJ
Squella
J A
JA
D002121:Calcium Channel Blockers / Q000737:chemistry*; D003505:Cyclodextrins / Q000737:chemistry*; D004095:Dihydropyridines / Q000737:chemistry*; D004563:Electrochemistry; D015394:Molecular Structure; D012995:Solubility; D013056:Spectrophotometry, Ultraviolet; D047392:beta-Cyclodextrins
D002121:Calcium Channel Blockers; D003505:Cyclodextrins; D004095:Dihydropyridines; D047392:beta-Cyclodextrins; C082391:furnidipine; C031215:betadex