Study On The Inclusion Behavior Of Menthol And Menthone By Cyclodextrin Derivatives

Volatile oils are one vital kind of active constituents in Chinese herbal medicine which are intricately-formed and poor-stable,so we use the technology of cyclodextrin inclusion to improve the stability of volatile oils and to make preparation more convenient.Several derivatives of?-cyclodextrin(?-CD)such as hydroxypropyl-?-cyclodextrin(HP-?-CD),methyl-?-cyclodextrin(ME-?-CD)and sulfurbutyl-?-cyclodextrin(SBE-?-CD)are often used as the inclusion material because of the poor water solubility and strong hemolysis of?-CD.Usually the evaluating indicators of inclusion technology of volatile oils are the yield and oil concentration of the inclusion complex,but the choice of inclusion material and quantitative index of the interaction of volatile oil and inclusion material are hard to be found in literature.We chooses menthol and menthone as model drugs,HP-?-CD,ME-?-CD,SBE-?-CD as inclusion materials to examine the inclusion equilibrium constant(K),the solubilization multiple combined with the solubility of the two drugs by including the two drugs alone and including the 2 drugs in mint oil together by different proportions(1:1,1:2 and 2:1)by phase-solubility method.The results show that all the 3 meterials can form an inclusion complex with a molar ratio of 1:1 with menthol and menthone,which are checked by means such as IR,DSC and TG.Menthol has a stronger combination ability with the 3 meterials than menthone.Generally,the law'HP-?-CD>ME-?-CD>SBE-?-CD' is applied to the combination ability of menthol and menthone with the 3 materials,but in mint oil,the law is 'ME-?-CD>SBE-?-CD>HP-?-CD'.And this lays a foundation for further study of the law of multi-components inclusion of volatile oils.