Preformulative and formulative studies on inclusion complexes between cyclodextrins and ursodeoxycholic acid

Three different methods (evaporation, spray-drying and lyophilisation) were used to prepare the complex between ursodeoxycholic acid and cyclodextrin (beta CD or HP beta CD). A small fraction of free drug not included into th e cyclodextrin cavity along with the complex was noticed only for the compl exes prepared using the evaporation method. Preformulative parameters of at least three batches of each complex were evaluated in view of the industri al preparation method selected. All the methods guarantee good reproducibil ity, but the surface area and the density of the complex powders were chief ly affected. Given the low-density value, the spray-dried and lyophilised c omplexes need to be transformed into granules before tablet preparation. Th e formulative parameters of the tablets were also evaluated. The disintegra tion test of both uncoated and coated tablets prepared with the granules ob tained form the different beta CD complexes was not satisfactory. In spite of the long disintegration time, the ursodeoxycholic acid dissolution rate from the tablets was similar to that observed in the case of the inclusion complex powders.