To evaluate the potential use of beta-cyclodextrin sulfobutyl ether, 7 sodium salt (SBE7-beta-CD) as a drug solubilizing and stabilizing agent, the solubilizing effects of SBE7-beta-CD on 22 different poorly water-soluble drugs were compared with those of intact beta-CD and heptakis-(2,6-di-O-methyl)-beta-CD (DMCD). SBE7-beta-CD was generally a more effective solubilizer for poorly water-soluble drugs than was intact beta-CD, but SBE7-beta-CD was not as effective as DMCD. The effects of SBE7-beta-CD on the acid hydrolysis rate of prostaglandin I2, the alkaline hydrolysis rate of indomethacin, the dehydration of prostaglandin E1, and the isomerization of prostaglandin A1 were also investigated and compared to those for intact beta-CD, DMCD, and 2,3,6 partially methylated-beta-CD (PMCD). The stabilizing effects of SBE7-beta-CD on chemically unstable drugs were generally higher than those of other CDs.