The aim of this study was to evaluate the effects of preparation method and the type of
surfactant on the properties of
cephalexin (CPX)
microspheres in order to obtain delivery systems suitable for the treatment of dairy
mastitis.
Microspheres were obtained using various preparation conditions and their physicochemical characteristics such as size, loading efficiency, morphology, and
drug crystallinity were investigated. Antibacterial activity of
microspheres from the optimum preparation condition was also studied. CPX
microspheres were prepared by two different W/O/W
emulsion solvent evaporation methods using PLGA as a matrix forming
polymer. Several types of
surfactants including nonionic, cationic, and anionic at different concentrations were used for preparation of the particles. The type and concentration of
surfactant did neither affect the size nor morphology of the
microspheres but showed a pronounced effect on the CPX encapsulation efficiency. It was found that
Tween 80 showed the highest
drug encapsulation efficiency (66.5%). Results from X-ray diffraction diffractograms and differential scanning calorimetry thermograms indicated that CPX entrapped in these microparticles was amorphous. Assessment of antibacterial activity showed that the obtained CPX
microspheres exhibited good inhibition with minimum inhibitory concentration and minimum bactericidal concentration values of 128 microg/mL and 2,048 mg/mL against Staphylococcus aureus ATCC 25923, 512 microg/mL and 4,096 mg/mL against Escherichia coli ATCC 25922, respectively.