Research About Synthesis And Composition Of 2-hydroxypropyl-β-cyclodextrin

2-hydroxypropyl-β-cyclodextrin is hydroxypropyled derivatives ofβ-CD. Compared to parentβ-CD, 2-hydroxypropyl-β-cyclodextrin is highly soluble, with advantages of less hemolysis action, bland, almost no metabolism in human bodies, etc. Therefore, 2-hydroxypropyl-β-cyclodextrin has much potential application in pharmacy and chiral separation. However, current research about 2-hydroxypropyl-β-cyclodextrin is confined in synthesis of several products with given degree of substitution, and application in increasing drug solubility,slowing release. There is very few papers about synthesis of 2-hydroxypropyl-β-cyclodextrin in wide range degree of substitution. Especially, no paper about the relation between synthesis condition,composition of products and chemical & physical character was published. In this paper, 2-hydroxypropyl-β-cyclodextrins with different degrees of substitutuion were synthesized fromβ-cyclodextrin and propylene oxide in sodium hydroxide solutions. Much work was focused on systemically research about synthesis condition, in order to find corresponding relation'synthesis condition—composition of products—area of application'.Series of experiments were processed through changes of concentration of alkali, ratio of reactants, and reaction time, under the theory of Central Composite Rotable Design. The degree of substitutuion and composition of products were investigated by DSC, ESI-MS, 1HNMR and 13CNMR instruments. We use response surface to analyse the influence of reaction parameters on degree of substitution.The result of experiments indicated: (1) concentration of alkali exerts much on the degree and position of substitution. With the increase of alkali concentration, the degree of substitution increases. 2-O-(2-HP)-β-CD is easily synthesized in lower alkali concentration, while 6-O-(2-HP)-β-CD is mostly synthesized in higher alkali concentration; (2) ratio of propylene oxide in reactant influences much on the degree of substitution. With the ratio of propylene oxide toβ-CD increasing from 7:1 to 21:1, the degree of substitution increases from 0.189 to 5.4317. When molar ratio of propylene oxide toβ-cyclodextrin is among 10:1~12:1, degree of substitution increases slowly. Products with different degree of substitution distribute symmetrically; (3) reaction time also exerts much on the degree and position of substitution. When reaction time increases, the degree of substitution increases too; (4) the result of response surface indicates that the degree of substitution is influenced by ratio of propylene oxide more than reaction time; (5) response surface can indicate the method to synthesize targeted product. Many different ways can produce the same targeted product. Based on their own status, the factories can choose the easiest method for them. That is significant in manufacture.