Synthesis And Adsorption Properties Of Crosslinked β - Cyclodextrin - Soluble Starch Polymeric Microspheres

According to the mechanism of reaction thatβ-cyclodextrin (β-CD) and water soluble starch can polymerize with epichlorohydrin (EPI), the polymer that have the ability to absorb the nonpolar compounds from their solutions was prepared. First, by studying the viscosity of the water phase the ratio of the material, interval of mixing time, mixing temperature and so on were decided. Then an inverse suspension polymerization method was used to synthesize the crosslinkedβ-CD and water soluble starch microspheres. During this process the factors affecting the particle size distribution of the droplets emulsified and the microspheres were researched. At last, the optimized technics of synthesis was decided.Fourier-transformed infrared analyses and thermoanalysis were used to prove the formed three diamensions network structures and characterization of microspheres. Good spherical shape was abserved under optical microscope and SEM. Swell rate research proves that the polymer microspheres can swell to an extent in different solutions.Using salicylic acid as model drug the process of absorption on polymer microspheres was studied. Such factors like temperature, initial concentration, the ratio of volume of ethanol, the character of polymer microspheres can influence the quantity of drug loading by absorption. Thermodynamics of absorption on polymer microspheres were studied to prove the physical absorption mechanism. Thermoanalysis, X ray Powder Diffraction and Fourier-transformed infrared spectroscopy were employed to characterize the microshperes absorbed drug to prove the amorphous state of drug absorbed on the microspheres. Using p-hydroxybenzoate,4-hydroxybenzoic acid methyl ester and 4-hydroxybenzoic acid propyl ester as model drugs, the conclusion that a stronger selective absorption of more nonpolar drug on polymer microspheres was gained.