Inclusion complexation of warfarin withβ-CDs
apparent binding constants
bioavailability of warfarin
Springer Online Journal Archives 1860-2000
Chemistry and Pharmacology
Abstract The inclusion complexes of warfarin withβ-cyclodextrin, 2-hydroxypropyl-β-CD and methyl-β-CD have been investigated in aqueous solution. The apparent binding constants of warfarin are found to be 542±19, 442±18 and 112±6M−1 respectively, calculated from the increments in fluorescence emission of the drug. The influence of theβ-CDs on the absorption rate of the drug is investigated within situ experiments in a chronically isolated internal loop, in the small intestine of the rat. The first-order disappearance (absorption) rate constant decreases to 3.6×10−4 min−1 inβ-CD, to 5.0×10−4 min−1 in 2-hydroxypropyl-β-CD and to 1.4×10−3 min−1 in methyl-β-CD compared to 3.2×10−3 min−1 in isotonic phosphate buffer (pH=7.4) solution, all of them showing a good agreement with the percentage of free warfarin in their complexed solutions: 16%, 18% and 47% calculated, respectively.
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