title: Physicochemical properties and drug release behavior of biguanidino and O-carboxymethyl chitosan microcapsules.
abstract: Two types of microcapsules (MCs) were prepared by the emulsion cross-linking method, where biguanidino chitosan (BGCS)and O-carboxymethyl chitosan (O-CMCS) served as the wall materials, and the antibacterial agent 2,4-diamino-6-(2-pyridyl)-1,3,5-triazine (PyTNH) served as a model water-soluble drug. The physicochemical performance of the MCs and their drug release behavior were investigated by Fourier transform infrared spectroscopy, thermogravimetric analysis/derivative thermogravimetric analysis, scanning electron microscopy, and swelling and in vitro drug release studies of the two MCs with unmodified chitosan-MCs (CS-MCs) used as the control. The results indicated that the degree of cross-linking, encapsulation efficiency, and thermal stability of the shell wall of the BGCS-microcapsules (BGCS-MCs) were much higher than those of the control and the O-CMCS-microcapsules (CMCS-MCs), owing to the reduction of steric hindrance and development of the conjugation effect in the cross-linking process. Studies on the swelling and in vitro drug-release behavior revealed a sustained release effect of the BGCS-MCs. Moreover, the CMCS-MCs were found to exhibit a pH-dependent drug release behavior, which can be attributed to the successive formation of H-bonds and repulsive forces with the change in the pH of the medium. Based on these results, the swelling-release models and the drug release kinetics of BGCS-MCs and CMCS-MCs are proposed.
authors.affiliation: College of Science, South China Agricultural University, Guangzhou, China.
authors.forename: Weiqiang
authors.initials: W
authors.lastname: Huo
authors.affiliation: College of Life Science, South China Agricultural University, Guangzhou, China.
authors.forename: Weixin
authors.initials: W
authors.lastname: Zhang
authors.affiliation: College of Science, South China Agricultural University, Guangzhou, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: College of Science, South China Agricultural University, Guangzhou, China; Institute of Biomaterial, South China Agricultural University, Guangzhou, China. Electronic address: xhzhou@scau.edu.cn.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Zhou
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage; D001645:Biguanides / Q000737:chemistry*; D002214:Capsules / Q000737:chemistry*; D048271:Chitosan / Q000031:analogs & derivatives* / Q000737:chemistry; D004337:Drug Carriers / Q000737:chemistry; D065546:Drug Liberation; D007700:Kinetics; D008826:Microbial Sensitivity Tests; D008855:Microscopy, Electron, Scanning; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000900:Anti-Bacterial Agents; D001645:Biguanides; D002214:Capsules; D004337:Drug Carriers; C504164:O-carboxymethylchitosan; D048271:Chitosan
keywords: Drug release behavior; Microcapsule; Modified chitosan