title: Characterization of hydrophobized pullulan with various hydrophobicities.
abstract: In this study, we prepared self-assembling nanospheres of hydrophobized pullulan. Pullulan acetate (PA), as hydrophobized pullulan, was synthesized by the acetylation of pullulan. PA derivatives were synthesized by changing the degree of acetylation. PA was characterized by Fourier transform infrared (FT-IR), X-ray diffractometry (XRD), and differential scanning calorimetry (DSC). The particle size distribution of the PA was determined using photon correlation spectroscopy (PCS) and the number-average particle size was found to depend upon the degree of acetylation of PA. Morphology by transmission electron microscopy (TEM) and scanning electron microscopy (SEM) showed the PA nanospheres were spherical in shape. The fluorescence probe technique was used to study the self-association behavior of hydrophobized pullulans in water using pyrene as a hydrophobic probe. The critical association concentration (CAC) values were determined from the fluorescence excitation spectra, CAC values were dependent upon the degree of acetylation. Drug release studies using clonazepam (CNZ) as a hydrophobic model drug showed that the increased drug contents and increased degree of acetylation resulted in a slower release rate of drug from the nanospheres.
authors.affiliation: College of Pharmacy, Chosun University, #375 Seosuk-dong, Dong-gu, Gwangju 501-759, South Korea.
authors.forename: Sun-Woong
authors.initials: SW
authors.lastname: Jung
authors.forename: Young-Il
authors.initials: YI
authors.lastname: Jeong
authors.forename: Sung-Ho
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000107:Acetylation; D000927:Anticonvulsants / Q000737:chemistry; D002152:Calorimetry, Differential Scanning; D002998:Clonazepam / Q000737:chemistry; D003460:Crystallization; D004337:Drug Carriers / Q000737:chemistry*; D005936:Glucans / Q000737:chemistry*; D006207:Half-Life; D057927:Hydrophobic and Hydrophilic Interactions; D007700:Kinetics; D008854:Microscopy, Electron; D008863:Microspheres; D036103:Nanotechnology; D010316:Particle Size; D013057:Spectrum Analysis; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D000927:Anticonvulsants; D004337:Drug Carriers; D005936:Glucans; D002998:Clonazepam; C009109:pullulan