Chitosan and β-cyclodextrin were used to prepare microspheres with theophylline for pulmonary delivery by spray drying method. The characteristics, mucociliotoxicity, permeation rate and drug release were studied. Th...Chitosan and β-cyclodextrin were used to prepare microspheres with theophylline for pulmonary delivery by spray drying method. The characteristics, mucociliotoxicity, permeation rate and drug release were studied. The drug entrapments of microspheres Ⅰ, Ⅱ and Ⅲ were from 35.70% to 21.09% and 13.33%, while yields and encapsulation efficiencies were higher than 45% and about 90% respectively. The microspheres possessed low tap densities （0.34-0.48 g/cm^3）, appropriate diameters （3.35-3.94 μm） and theoretical aerodynamics diameters （2.20-3.04 μm）. SEM images showed the microspheres were spherical with smooth or wrinkled surface surfaces. FT-IR demonstrated theophylline had formed hydrogen bonds with chitosan and fl-cyclodextrin. The microspheres could effectively reduce the ciliotoxicity and easy to penetrate the memberine. The in vitro release of the microspheres was related to the ratio of drug/polymer and microspheres Ⅱ had a prolong release, providing the release of 72.00% in 12 h. The results suggestes that chitosan/β-cyclodextrin microspheres Ⅱ are a promising carrier as sustained release for pulmonary delivery.展开更多
A series of chitosan/attapulgite (CTS/APT) hybrid microspheres were prepared by a facile spray-drying technique. The developed hybrid microspheres were characterized by Fourier transform infrared spectra (FTIR), X-ray...A series of chitosan/attapulgite (CTS/APT) hybrid microspheres were prepared by a facile spray-drying technique. The developed hybrid microspheres were characterized by Fourier transform infrared spectra (FTIR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and the zeta potential. The encapsulation efficiency and in vitro controlled release properties of the microspheres for drug were evaluated using diclofenac sodium (DS) as a model drug. Results indicated that the introduction of APT into crosslinked CTS microspheres can achieve narrow size distribution and make them more uniform. The isoelectric point of the microspheres increased from 8.14 to 9.18 with increasing the content of APT to 10 wt.%. DS loaded in hybrid microspheres is hardly released in simulated gastric fluid, but quickly released in simulated intestinal fluid. The electrostatic interaction between hybrid microspheres and DS can improve the encapsulation efficiency and controlled release behavior of CTS/APT microspheres, and the release mechanism fits Fickian diffusion.展开更多
基金the National Natural Science Foundation of China(No.30670566)Natural Science Foundation of Shandong Province
文摘Chitosan and β-cyclodextrin were used to prepare microspheres with theophylline for pulmonary delivery by spray drying method. The characteristics, mucociliotoxicity, permeation rate and drug release were studied. The drug entrapments of microspheres Ⅰ, Ⅱ and Ⅲ were from 35.70% to 21.09% and 13.33%, while yields and encapsulation efficiencies were higher than 45% and about 90% respectively. The microspheres possessed low tap densities （0.34-0.48 g/cm^3）, appropriate diameters （3.35-3.94 μm） and theoretical aerodynamics diameters （2.20-3.04 μm）. SEM images showed the microspheres were spherical with smooth or wrinkled surface surfaces. FT-IR demonstrated theophylline had formed hydrogen bonds with chitosan and fl-cyclodextrin. The microspheres could effectively reduce the ciliotoxicity and easy to penetrate the memberine. The in vitro release of the microspheres was related to the ratio of drug/polymer and microspheres Ⅱ had a prolong release, providing the release of 72.00% in 12 h. The results suggestes that chitosan/β-cyclodextrin microspheres Ⅱ are a promising carrier as sustained release for pulmonary delivery.
文摘A series of chitosan/attapulgite (CTS/APT) hybrid microspheres were prepared by a facile spray-drying technique. The developed hybrid microspheres were characterized by Fourier transform infrared spectra (FTIR), X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and the zeta potential. The encapsulation efficiency and in vitro controlled release properties of the microspheres for drug were evaluated using diclofenac sodium (DS) as a model drug. Results indicated that the introduction of APT into crosslinked CTS microspheres can achieve narrow size distribution and make them more uniform. The isoelectric point of the microspheres increased from 8.14 to 9.18 with increasing the content of APT to 10 wt.%. DS loaded in hybrid microspheres is hardly released in simulated gastric fluid, but quickly released in simulated intestinal fluid. The electrostatic interaction between hybrid microspheres and DS can improve the encapsulation efficiency and controlled release behavior of CTS/APT microspheres, and the release mechanism fits Fickian diffusion.
