Poly(D,L-Lactic-Co-Glycolic Acid) (PLGA) copolymers have been extensively used as controlled-release carriers for many hydrophilic drugs because they are non-toxic, biodegradable, bioavailable, and biocompatible. In g...Poly(D,L-Lactic-Co-Glycolic Acid) (PLGA) copolymers have been extensively used as controlled-release carriers for many hydrophilic drugs because they are non-toxic, biodegradable, bioavailable, and biocompatible. In general, PLGA particles have been produced by a solvent evaporation technique utilizing water-in-oil-in-water (W/O/W) emulsions. However, W/O/W emulsions are unstable, causing the outer and inner aqueous phases to easily fuse during particle preparation. Consequently, a sufficient amount of drug was not encapsulated inside the particles. In this study, we examined a new particle preparation method utilizing a solid-in-oil-in-water (S/O/W) emulsion technique. The advantages of S/O/W emulsions, wherein a surfactant-drug complex disperses into the oil phase, were as follows: 1) leakage of hydrophilic drugs from the emulsions was inhibited, and 2) facile control over the emulsion particle size. Thus, the PLGA particles prepared by this method showed high encapsulation efficiency of drugs and formation of fine particles of submicron size by membrane emulsification were achieved.展开更多
An innovative application ofthe solventevaporation technique was suggested.Solventevaporation tech nique is a technique for drug encapsulation and nanosphere preparation.The widely used technique is also facing the pr...An innovative application ofthe solventevaporation technique was suggested.Solventevaporation tech nique is a technique for drug encapsulation and nanosphere preparation.The widely used technique is also facing the problem of low actual drug entrapment percent,which is not economic from the industrial view.The goal of this work is trying to use the advantage of this technique concerning the product sphericity and the ability to control particle size,to prepare a drug as pure crystals spheres.Ibuprofen is selected as a model drug.The spheres are formed by using Polyvinyl pyrrolidone(PVP)or Polyethylene glycol(PEG)as an anti-aggregating agent but not formed on using tween or span.Particle size and actual drug content depend on the concentrations the anti-aggregating agent used.Surfaces of the drug crystal spheres are porous with empty sphere internal structure on using PvP but spongy and rough on using PEG.The drug has its identity chemical form in the drug crystal spheres.IR scan of spheres prepared on using PEG showed a characteristic ether peak.DSC showed melting endothermic peak of PEG,but X-ray showed minor change in the drug crystal patterns.Drug release profiles from crystal spheres prepared with the same anti-aggregating agent are close to each other.The drug release profiles from drug crystal spheres prepared by using PEG are more controlled than that prepared by using PVP.The drug release mechanism is diffusion.It was concluded that,the same technique could be suggested for preparation ofother biomedical material in pure crystals spheres with controlled particle size.These properties may encourage to prepare very small particles with spherical shape for inhalation or injection as an innovative particle technology application for the widely used technique.展开更多
[Objectives]To prepare 20(S)-protopanaxadiol PLGA nanoparticles(20(S)-PPD-PLGA-NPs).[Methods]20(S)-PPD-PLGA-NPs were prepared by emulsion solvent evaporation method,and the optimal formulation was screened by Box-Behn...[Objectives]To prepare 20(S)-protopanaxadiol PLGA nanoparticles(20(S)-PPD-PLGA-NPs).[Methods]20(S)-PPD-PLGA-NPs were prepared by emulsion solvent evaporation method,and the optimal formulation was screened by Box-Behnken experiment with particle size and drug loading as the indicators through single factor experiment,and the drug release in vitro was carried out.[Results]The average diameter of the nanoparticles was(119.60±2.29)nm and the polydispersity index was(0.12±0.02),the size was uniform.The encapsulation efficiency and drug loading of protopanaxadiol were(87.99±1.29)%and(14.86±0.25)%,respectively.[Conclusions]The 20(S)-PPD-PLGA-NPs were successfully prepared by emulsion solvent evaporation method,and the 20(S)-PPD-PLGA-NPs had good stability,to lay a foundation for the study of 20(S)-PPD-PLGA-NPs in vitro and in vivo.展开更多
Biodegradable triblock copolymer PLA/PEG/PLA was synthesized by ring-opening bulk polymerization of D,L-lactide in the presence of poly(ethylene glycol) (PEG), in the molecular structure of which, the length of PEG an...Biodegradable triblock copolymer PLA/PEG/PLA was synthesized by ring-opening bulk polymerization of D,L-lactide in the presence of poly(ethylene glycol) (PEG), in the molecular structure of which, the length of PEG and PLA chain segments was made to be quite different. Nanoparticles were prepared by using the copolymer via a double emulsion-evaporation technique. The paticles tended to form the configuration like capsules, i.e., the nanocapsules, because of the great size difference in PEG and PLA segments of the copolymer. Insulin, chosen as a model drug, was encapsulated into nanocapsules. The effect of preparation conditions on the size, insulin encapsulation efficiency, and in vitro drug release behavour of the nanoparticles were investigated. The experimental results show that the nanocapsules had a smooth spherical surface and the mean diameter was in the range from 180 nm to 350 nm, and the entrapment of insulin achieved up to 78.4. The drug-loaded nanocapsules released their content continuously, remarkably different from the corresponding micelles which gave a significant initial burst release followed by a slow release.展开更多
文摘Poly(D,L-Lactic-Co-Glycolic Acid) (PLGA) copolymers have been extensively used as controlled-release carriers for many hydrophilic drugs because they are non-toxic, biodegradable, bioavailable, and biocompatible. In general, PLGA particles have been produced by a solvent evaporation technique utilizing water-in-oil-in-water (W/O/W) emulsions. However, W/O/W emulsions are unstable, causing the outer and inner aqueous phases to easily fuse during particle preparation. Consequently, a sufficient amount of drug was not encapsulated inside the particles. In this study, we examined a new particle preparation method utilizing a solid-in-oil-in-water (S/O/W) emulsion technique. The advantages of S/O/W emulsions, wherein a surfactant-drug complex disperses into the oil phase, were as follows: 1) leakage of hydrophilic drugs from the emulsions was inhibited, and 2) facile control over the emulsion particle size. Thus, the PLGA particles prepared by this method showed high encapsulation efficiency of drugs and formation of fine particles of submicron size by membrane emulsification were achieved.
文摘An innovative application ofthe solventevaporation technique was suggested.Solventevaporation tech nique is a technique for drug encapsulation and nanosphere preparation.The widely used technique is also facing the problem of low actual drug entrapment percent,which is not economic from the industrial view.The goal of this work is trying to use the advantage of this technique concerning the product sphericity and the ability to control particle size,to prepare a drug as pure crystals spheres.Ibuprofen is selected as a model drug.The spheres are formed by using Polyvinyl pyrrolidone(PVP)or Polyethylene glycol(PEG)as an anti-aggregating agent but not formed on using tween or span.Particle size and actual drug content depend on the concentrations the anti-aggregating agent used.Surfaces of the drug crystal spheres are porous with empty sphere internal structure on using PvP but spongy and rough on using PEG.The drug has its identity chemical form in the drug crystal spheres.IR scan of spheres prepared on using PEG showed a characteristic ether peak.DSC showed melting endothermic peak of PEG,but X-ray showed minor change in the drug crystal patterns.Drug release profiles from crystal spheres prepared with the same anti-aggregating agent are close to each other.The drug release profiles from drug crystal spheres prepared by using PEG are more controlled than that prepared by using PVP.The drug release mechanism is diffusion.It was concluded that,the same technique could be suggested for preparation ofother biomedical material in pure crystals spheres with controlled particle size.These properties may encourage to prepare very small particles with spherical shape for inhalation or injection as an innovative particle technology application for the widely used technique.
文摘[Objectives]To prepare 20(S)-protopanaxadiol PLGA nanoparticles(20(S)-PPD-PLGA-NPs).[Methods]20(S)-PPD-PLGA-NPs were prepared by emulsion solvent evaporation method,and the optimal formulation was screened by Box-Behnken experiment with particle size and drug loading as the indicators through single factor experiment,and the drug release in vitro was carried out.[Results]The average diameter of the nanoparticles was(119.60±2.29)nm and the polydispersity index was(0.12±0.02),the size was uniform.The encapsulation efficiency and drug loading of protopanaxadiol were(87.99±1.29)%and(14.86±0.25)%,respectively.[Conclusions]The 20(S)-PPD-PLGA-NPs were successfully prepared by emulsion solvent evaporation method,and the 20(S)-PPD-PLGA-NPs had good stability,to lay a foundation for the study of 20(S)-PPD-PLGA-NPs in vitro and in vivo.
文摘Biodegradable triblock copolymer PLA/PEG/PLA was synthesized by ring-opening bulk polymerization of D,L-lactide in the presence of poly(ethylene glycol) (PEG), in the molecular structure of which, the length of PEG and PLA chain segments was made to be quite different. Nanoparticles were prepared by using the copolymer via a double emulsion-evaporation technique. The paticles tended to form the configuration like capsules, i.e., the nanocapsules, because of the great size difference in PEG and PLA segments of the copolymer. Insulin, chosen as a model drug, was encapsulated into nanocapsules. The effect of preparation conditions on the size, insulin encapsulation efficiency, and in vitro drug release behavour of the nanoparticles were investigated. The experimental results show that the nanocapsules had a smooth spherical surface and the mean diameter was in the range from 180 nm to 350 nm, and the entrapment of insulin achieved up to 78.4. The drug-loaded nanocapsules released their content continuously, remarkably different from the corresponding micelles which gave a significant initial burst release followed by a slow release.
