Improvement of the oral bioavailability of digitalis glycosides by cyclodextrin complexation.
Inclusion complexes of the digitalis glycosides digitoxin, digoxin, and methyl digoxin with three cyclodextrins (alpha-, beta-, gamma-homologues) in water and in the solid state were studied by a solubility method, IR and 1H-NMR spectroscopy, and X-ray diffractometry. Solid complexes (in a molar ratio of 1:4) of the digitalis glycosides with gamma-cyclodextrin were prepared and their in vivo absorption examined. The rapidly dissolving form of the gamma-cyclodextrin complex significantly increased plasma levels of digoxin (approximately 5.4-fold) after oral administration to dogs.
D000818:Animals; D001682:Biological Availability; D002626:Chemistry, Pharmaceutical; D003505:Cyclodextrins / Q000008:administration & dosage* / Q000378:metabolism; D003912:Dextrins / Q000008:administration & dosage*; D004071:Digitalis Glycosides / Q000008:administration & dosage* / Q000378:metabolism; D004285:Dogs; D005260:Female; D007408:Intestinal Absorption; D007700:Kinetics; D009682:Magnetic Resonance Spectroscopy; D012995:Solubility; D013213:Starch / Q000008:administration & dosage*; D014961:X-Ray Diffraction
D003505:Cyclodextrins; D003912:Dextrins; D004071:Digitalis Glycosides; D013213:Starch