title: The controlled release of tilmicosin from silica nanoparticles.
abstract: The aim of this study was to use silica nanoparticles as the carrier for controlled release of tilmicosin. Tilmicosin was selected as a drug model molecule because it has a lengthy elimination half-life and a high concentration in milk after subcutaneous administration. Three samples of tilmicosin-loaded silica nanoparticles were prepared with different drug-loading weight. The drug-loading weight in three samples, as measured by thermal gravimetric analysis, was 29%, 42%, and 64%, respectively. With increased drug-loading weight, the average diameter of the drug-loaded silica nanoparticles was increased from 13.4 to 25.7 nm, and the zeta potential changed from-30.62 to-6.78 mV, indicating that the stability of the drug-loaded particles in the aqueous solution decreases as drug-loading weight increases. In vitro release studies in phosphate-buffered saline showed the sample with 29% drug loading had a slow and sustained drug release, reaching 44% after 72 h. The release rate rose with increased drug-loading weight; therefore, the release of tilmicosin from silica nanoparticles was well-controlled by adjusting the drug loading. Finally, kinetics analysis suggested that drug released from silica nanoparticles was mainly a diffusion-controlled process.
authors.affiliation: College of Sciences, Henan Agricultural University, Zhengzhou, P. R. China. smr770505@yahoo.com.cn
authors.forename: Meirong
authors.initials: M
authors.lastname: Song
authors.forename: Yanyan
authors.initials: Y
authors.lastname: Li
authors.forename: Cailing
authors.initials: C
authors.lastname: Fai
authors.forename: Shumin
authors.initials: S
authors.lastname: Cui
authors.forename: Baoan
authors.initials: B
authors.lastname: Cui
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000737:chemistry; D003692:Delayed-Action Preparations; D004058:Diffusion; D004355:Drug Stability; D007700:Kinetics; D053758:Nanoparticles; D010316:Particle Size; D012822:Silicon Dioxide / Q000737:chemistry*; D013818:Thermogravimetry; D013997:Time Factors; D015645:Tylosin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D003692:Delayed-Action Preparations; D012822:Silicon Dioxide; C052319:tilmicosin; D015645:Tylosin