Abstract
Cyclodextrins are popular drug solubilizers, but the use of the natural cyclodextrins is hampered by their tendency to coprecipitate with the drug. To understand and overcome such problems, we have studied the solubility of dexamethasone in the presence of natural β-cyclodextrin and γ-cyclodextrin, individually and in various combinations. Equilibrium models of the phase-solubility diagrams with individual cyclodextrins revealed that dexamethasone was solubilized as 1:1 complexes, but formation of insoluble higher-order complexes set an upper limit to the concentration of solubilized dexamethasone. This limit could be raised from 8 to 17 mM by using combinations of the two cyclodextrins, as their solubilizing properties were additive in some regions of the phase-solubility diagram and synergistic in other regions. The additive effects arise from the additivity of solubilities-the same phenomenon contributes to the good solubilizing properties of many modified cyclodextrins. The synergistic effects, however, could not be explained. The results open up for an increased use of the natural cyclodextrins as an improved alternative to modified cyclodextrins.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
