Silver-coated magnetic nanoparticles as an efficient delivery system for the antibiotics trimethoprim and sulfamethoxazole against E. Coli and S. aureus: release kinetics and antimicrobial activity

Biometals. 2021 Dec;34(6):1237-1246. doi: 10.1007/s10534-021-00338-5. Epub 2021 Aug 22.


Trimethoprim and sulfamethoxazole are prescribed for a broad spectrum of bacteria. However, the use of these medicines is restricted due to the risk of microbial resistance in the body. Nanotechnology is a strategy for overcoming this problem by helping develop novel drug delivery systems. This study aims to assess the ability of Fe3O4/Ag and Fe3O4@SiO2/Ag nanoparticles to improve efficiency of the traditional formulation of trimethoprim and sulfamethoxazole. Fe3O4/Ag and Fe3O4@SiO2/Ag were found to have sphere-like morphologies with average sizes of 33.2 and 35.1 nm, respectively. The values of the zeta potential for the pure sulfamethoxazole and trimethoprim were -30.6 and -10.0 mV, respectively, which increased to zero or even larger positive values after being conjugated with the NPs. The study of the release kinetics showed that 64.7% of the medicines were released from the carriers within 40 days. The values of MIC for sulfamethoxazole, trimethoprim, Fe3O4/Ag/sulfamethoxazole, Fe3O4/Ag/trimethoprim, Fe3O4@SiO2/Ag/sulfamethoxazole, and Fe3O4@SiO2/Ag/trimethoprim against Escherichia coli were calculated to be 12, 9, 4, 4, 4, and 4 μg/mL, respectively. Besides, the relevant values against Staphylococcus aureus were measured to be 12, 9, 4, 4, 3, and 2 μg/mL, respectively. The use of synthesized nanomaterials for the delivery of these antibiotics leads to smaller doses compared to their traditional forms.

Keywords: Drug delivery systems; Peppas equation; Release profiles; Sulfamethoxazole; Trimethoprim.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / chemistry
  • Anti-Bacterial Agents / pharmacology
  • Escherichia coli
  • Kinetics
  • Magnetite Nanoparticles* / chemistry
  • Methicillin-Resistant Staphylococcus aureus*
  • Microbial Sensitivity Tests
  • Silicon Dioxide / chemistry
  • Silver / chemistry
  • Silver / pharmacology
  • Staphylococcus aureus
  • Sulfamethoxazole / pharmacology
  • Trimethoprim / pharmacology


  • Anti-Bacterial Agents
  • Magnetite Nanoparticles
  • Silver
  • Silicon Dioxide
  • Trimethoprim
  • Sulfamethoxazole