Effect of hydroxypropyl-β-cyclodextrin on solubility of rubidate

OBJECTIVE To investigate the enhancement of dissolution and solubility of rubidate by its complexation with hydroxypropyl-β-cyclodextrinHP-β-CD).METHODS The inclusion complexes of rubidate/HP-β-CD were prepared by co-evaporating.The apparent solubility and in vitro dissolution characteristics of inclusion complexes were determined and compared with free rubidate and its physical mixture.The binary systems of rubidate and HP-β-CD were characterized by differential scanning calorimetry.RESULTS The apparent solubility of rubidate and its inclusion complexes prepared from rubidate and HP-β-CD at different molar ratios(1∶1,1∶1.5,1∶2)were 18.33,117.81,112.66,100.76 mg·L-1 at 37 ℃,respectively,and their 45 min dissolution rates were 49.99%,90.27%,94.84% and 90.78%,respectively.In the same ratio,the dissolution rates of the inclusion complexes were higher than those of their physical mixtures.Characteristic peak of rubidate in DSC curve of inclusion complex disappeared.CONCLUSION The solubility and dissolution rate of rubidate are increased by HP-β-CD inclusion complexation evidently.