DISSOLUTION CHARACTERISTICS OF NIFEDIPINE COMPLEXES WITH BETA-CYCLODEXTRINS

Formation of nifedipine complexes with beta-cyclodextrin, hydroxypropy l-beta-cyclodextrin, and DIMEB in solution was studied by the phase so lubility method. Solid complexes of nifedipine were prepared by partia l and complete solubilization of nifedipine using the freeze- and spra y-drying techniques. The complexation led to an improvement in the dis solution rate of the drug. The relative potency of beta-cyclodextrins to enhance the dissolution rate of nifedipine was in order: beta-cyclo dextrin < hydroxypropyl-beta-cyclodextrin < DIMEB, which clearly fits the magnitude of stability constant data of the complexes. The dissolu tion rates of the free drug, complexes, and physical mixture of drug a nd cyclodextrins from constant surface area disks were also investigat ed.