The Molecular Recognition And Drug Inclusion Behavior Research Of β-Cyclodextrin

Due to the unique structure with hydrophile exterior and hydrophobic central cavity,β-cyclodextrins (β-CDs) can selectively bind different guest molecules with suitable shape and size to form inclusion complexes. In the inclusion complexes forming process, there was no covalent bond breaking and it did not generate a new covalent bond, It mainly based on the role of weak interactions, including Van der Waals forces, hydrophobic interaction, hydrogen bonding, matching function in host-guest moleculars, etc.β-cyclodextrin inclusion complexes could change physical appearances or chemical properties of the guest molecules, such as, solubility, toxicity, spectral, stability and targeting. Soβ-cyclodextrin been widely applied in many fields, including foods, drugs, analytics, electrochemistry, environment and so on.In this paper, the use ofβ-cyclodextrin as host molecules was investigated. The article studied the molecular recognition behaviors with the bifunctional molecules containing benzene such as p-hydroxybenzoic acid and the inclusion features with drugs such as ascorbic acid.The experiments can be divided into two parts:1.P-hydroxybenzoic acid, o-nitroaniline, m-nitrophenol were used as guest molecules to study the molecular recognition behaviors in the water withβ-cyclodextrin. The inclusion complexes ofβ-cyclodextrin with guest molecules were characterized by means of the IR and 1HNMR measurements.Furthermore, its inclusion models were infered. The results showed that the host molecules and guest molecules formed inclusion complexes with the molar ratios of 1:1; the stability of inclusion complexes was related to the guest molecules'space strctures, substituted fuctions and the hydrophobicity of the substituted fuctions.2.Ascorbic acid, thymol and benzoin have been used as the drug molecules to investigate their solubilization and stabilization properties with host moleculesβ-cyclodextrin. An optional condition was established by the orthogonal design of four factors and three levels. The inclusion rate and yield coefficient were used as criteria of selecting the optional condition.The best techniques of the inclusion compound ofβ-cyclodextrin- ascorbic acid preparation was that the molecular ratio of ascorbic acid toβ-cyclodextrin was 1:1 by grinding and inclusion time was four hours and inclusion temperature was 40℃and stirring date was 500 r/min;the best techniques of the inclusion compound ofβ-cyclodextrin- thymol preparation was that the molecular ratio of thymol toβ-cyclodextrin was 1:1 by grinding and inclusion time was six hours and inclusion temperature was 40℃and stirring date was 500 r/min; The best techniques of the inclusion compound ofβ-cyclodextrin- benzoin preparation was that the molecular ratio of benzoin toβ-cyclodextrin was 1:1 by grinding and inclusion time was four hours and inclusion temperature was 60℃and stirring date was 1000 r/min. The content of the drug molecules was determined through HPLC and inclusion rate was calculated. The results showed that the forming of inclusion complexes betweenβ-cyclodextrin and drug molecules can increase the solubility of drug molecules. The inclusion complexes ofβ-cyclodextrin with guest molecules were characterized by means of 1HNMR measurements. The results showed that the host molecules and guest molecules formed inclusion complexes with the molar ratios of 1:1.