Cephalexin nanoparticles: Synthesis, cytotoxicity and their synergistic antibacterial study in combination with silver nanoparticles

•The synthesis of cephalexin nanoparticles from bulk cephalexin powders is reported using ball milling method.•The solubility of cephalexin in water was effectively enhanced through the prepared nanoparticles.•IC50 test revealed no toxicity for the prepared cephalexin solutions after milling.•Synergistic antibacterial properties were observed against Staphylococcus aureus in the presence of silver nanoparticles.

Developing of new antibiotics with synergistic properties is of great importance. Herein, the synthesis of cephalexin nanoparticles (CPNPs) is reported through ball milling method for the first time. Cephalexin powders had an initial size in the range of 10-100 μm. The average particle size, however, was reduced to about 100 nm after milling for 7 h, confirmed by SEM. Silver nanoparticles (AgNPs) with small particle size (<10 nm) were synthesized through chemical reduction of silver ions in citrate solution. The cytotoxicity of the prepared CPNPs and AgNPs at different concentrations were evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction assay. The antibacterial properties of CPNPs, AgNPs and their combination were investigated against Staphylococcus aureus. The results confirmed that AgNPs show synergistic properties in the presence of CPNPs and effectively increased their antibacterial properties.