Surface fabrication of hollow microspheres from N-methylated chitosan cross-linked with glutaraldehyde.
We have successfully prepared biocompatible and biodegradable hollow microspheres with sizes between 2 and 5 mum using cyclohexane droplets as a template and the N-methylated chitosan (NMC) cross-linked with glutaraldehyde (GA) as the shell. The structure, morphology, and formation process of the hollow microspheres were characterized by FT-IR, (1)H and (13)C NMR, scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The results revealed that the microspheres exhibited a very smooth and hollow structure. This work confirmed that the hollow microspheres were accomplished by fabricating on the basis of chemical cross-linking on the surface of the emulsion droplets and by removing cyclohexane as core. The results from SEM and TEM indicated that the emulsion droplets covered with cross-linked NMC in the oil-in-water system aggregated together to form a precipitate of microspheres by coagulating with acetone. Moreover, the cross-linked NMC on the surface of the microspheres continuously cured to form the tight shell, whereas the inner area became a cavity with increase of the aging time, leading to the hollow microspheres. In addition, an anti-infective drug, ofloxacin (Floxin), encapsulated in the microspheres more rapidly released to reach 90 wt % at pH 7.4 within 8 h than at pH 1.2.
Peng
Xianghong
X
Department of Chemistry, Wuhan University, Wuhan 430072, China.
Zhang
Lina
L
D001672:Biocompatible Materials / Q000138:chemical synthesis* / Q000737:chemistry; D048271:Chitosan / Q000737:chemistry*; D003432:Cross-Linking Reagents; D004337:Drug Carriers; D005976:Glutaral; D009682:Magnetic Resonance Spectroscopy; D008855:Microscopy, Electron, Scanning; D008863:Microspheres; D015242:Ofloxacin / Q000008:administration & dosage; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties
D001672:Biocompatible Materials; D003432:Cross-Linking Reagents; D004337:Drug Carriers; D048271:Chitosan; D015242:Ofloxacin; D005976:Glutaral