INCLUSION COMPLEXATION OF INDOMETHACIN WITH CYCLODEXTRINS IN SOLUTIONAND IN THE SOLID-STATE

Complex formation of indomethacin with alpha-, beta- and gamma-cyclode xtrins and dimethyl beta-cyclodextrin (DIMEB) were studied by the solu bility and UV spectrophotometric methods. By comparing the apparent st ability constants evaluated by the two methods, it was possible to cha racterize the stability of the inclusion complexes and to establish, i n part, their stoichiometries. The solid complexes of indomethacin wit h cyclodextrins in molar ratios of 1/1 were prepared by employing the freeze-drying technique. The influence of cyclodextrins on diffusion t hrough a semi-permeable membrane were evaluated according to the first -order kinetics of diffusion from the solutions containing indomethaci n alone or in the complex form. The apparent dialytic rate constants o f the complexes were lower than that of the free indomethacin.