We developed poly lactic-co-glycolic acid（PLGA） microspheres loaded with cefquinome and tested their effectiveness in a mouse model. The microspheres were prepared by optimizing several key parameters such as PLGA m...We developed poly lactic-co-glycolic acid（PLGA） microspheres loaded with cefquinome and tested their effectiveness in a mouse model. The microspheres were prepared by optimizing several key parameters such as PLGA molecular weight, drug/polymer ratio, internal water volume and ethyl acetate. Drug loading efficiency, stability, in vitro release and tissue distribution in mouse were evaluated. The average particle size of the microspheres was 27.84 μm. The drug loading efficiency was 64.57%. The in vitro release of cefquinome from microspheres after 4 h was about 40% compared with over 90% for the drug alone. The concentration of cefquinome in lung reached 25 μg/g 0.25 h after injection, and kept at 10 μg/g 4 h after injection. However, the concentration of cefquinome was very low in other organs even 0.25 h after injection. In conclusion, Cefquinome-loaded PLGA microspheres are compatible as an effective lung-targeting drug delivery system and have a good sustained release efficacy.展开更多
Swellable matrix represents one of the most employed controlled release systems. These dosage forms provide slow release of drugs to reduce the fluctuation of drug concentration in plasma in order to improve the effic...Swellable matrix represents one of the most employed controlled release systems. These dosage forms provide slow release of drugs to reduce the fluctuation of drug concentration in plasma in order to improve the efficiency of treatment and/or to reduce adverse effects. The application of the concepts of statistical physics has allowed discovering the existence of critical points in the formulation of swellable matrices. These points, representing the volume fractions of the tablet components where the properties of the matrix diverge or change suddenly, provide important knowledge of how to rationalize the design of swellable matrices. The critical points are generally related to the percolation threshold of one of the components of the formulation, which corresponds to a geometrical phase transition of this component, passing from isolation to spanning the whole system. The last section of the paper is devoted to more recent findings concerning the influence of particle size of the components on the percolation threshold of the matrix forming polymer, and therefore on the release behaviour of the matrix. Knowledge of the excipient percolation threshold allows a more rational design of swellable matrices, according to the guidelines of the regulatory authorities concerning science-based formulation and quality by design.展开更多
基金Funded by the national key research and development plan(No.2016YFD0501309)the National Natural Science Foundation of China(31402256)the High-level Talent Research Foundation of Qingdao Agricultural University,China(631206)
文摘We developed poly lactic-co-glycolic acid（PLGA） microspheres loaded with cefquinome and tested their effectiveness in a mouse model. The microspheres were prepared by optimizing several key parameters such as PLGA molecular weight, drug/polymer ratio, internal water volume and ethyl acetate. Drug loading efficiency, stability, in vitro release and tissue distribution in mouse were evaluated. The average particle size of the microspheres was 27.84 μm. The drug loading efficiency was 64.57%. The in vitro release of cefquinome from microspheres after 4 h was about 40% compared with over 90% for the drug alone. The concentration of cefquinome in lung reached 25 μg/g 0.25 h after injection, and kept at 10 μg/g 4 h after injection. However, the concentration of cefquinome was very low in other organs even 0.25 h after injection. In conclusion, Cefquinome-loaded PLGA microspheres are compatible as an effective lung-targeting drug delivery system and have a good sustained release efficacy.
文摘Swellable matrix represents one of the most employed controlled release systems. These dosage forms provide slow release of drugs to reduce the fluctuation of drug concentration in plasma in order to improve the efficiency of treatment and/or to reduce adverse effects. The application of the concepts of statistical physics has allowed discovering the existence of critical points in the formulation of swellable matrices. These points, representing the volume fractions of the tablet components where the properties of the matrix diverge or change suddenly, provide important knowledge of how to rationalize the design of swellable matrices. The critical points are generally related to the percolation threshold of one of the components of the formulation, which corresponds to a geometrical phase transition of this component, passing from isolation to spanning the whole system. The last section of the paper is devoted to more recent findings concerning the influence of particle size of the components on the percolation threshold of the matrix forming polymer, and therefore on the release behaviour of the matrix. Knowledge of the excipient percolation threshold allows a more rational design of swellable matrices, according to the guidelines of the regulatory authorities concerning science-based formulation and quality by design.
