Chitosan and β-cyclodextrin microspheres as pulmonary sustained delivery systems

Abstract

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 microspheresⅠ, Ⅱ and Ⅲ were from 35.70% to 21.09% and 13.33%, while yields and encapsulation effi ciencies 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 β-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.

The potential of chitosan for pulmonary drug delivery

“…Besides, they have the ability to provide a sustained release of the drug, releasing 72% in 12 hours (53,72).…”

Applications of Chitosan in Pulmonary Drug Delivery

“…Weifen Zhang's group had developed a series of CS-based microspheres for pulmonary administration. They reported the preparation of CS and β-cyclodextrin microspheres as PDDS [51][52][53][54][55]. The microspheres were prepared by the spray drying method, and theophylline was loaded into the microspheres as a model drug.…”

Flatness Analysis and Control of Strips with Different Thickness in 2250 mm Hot Tandem Rolling

“…The evolution of flatness and longitudinal residual stress of thick strip and thin strip in hot tandem rolling is analyzed based on the flatness calculation model expressed by Equation (6) to (9) and the elastic-plastic finite element model. The diameter of roll in F1 to F4 stand is set as 800 mm and that in F5 to F7 is set as 680 mm.…”

“…Zhang built a flatness calculation model via the ratio of crown to thickness, namely, relative crown. [9] Shohet proposed the flatness calculation model known as Shohet theoretical, [10] which is widely applied in traditional strip crown determination models. [11][12][13][14] Bao and Sun built flatness calculation models considering the effect of flatness of uneven distribution of transducers and transversal temperature difference of strip, respectively.…”