CONTEXT: There is a great necessity to find and use accomplished terminal 
sterilization technique for industrial manufacturing, research and development 
studies. Gamma (γ)-sterilization has been commonly employed for wide range of 
products as indicated by the pharmacopoeias. However, carefully examination 
should be performed prior to administration since γ-radiation can cause changes 
in drug and polymer excipients. No information is available in literature about 
γ-sterilization effects on vancomycin HCl-loaded poly (ɛ-caprolactone) (PCL) 
microspheres.
OBJECTIVE: Formulations were developed using a different preparation approach 
for the treatment of medical device-related osteomyelitis, and γ-sterilization 
effects on the physicochemical characterization of the formulations were 
examined.
METHODS: Water-in-oil-in-water (w/o/w) emulsion technique using polyvinyl 
alcohol (PVA) in inner and outer phase was applied to prepare formulations. 
Physicochemical properties of the formulations were investigated before and 
after γ-sterilization and the antibacterial activity against Staphylococcus 
aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis) were 
measured.
RESULTS: The particle size of the nonsterilized formulations were between 58 and 
134 μm. 60% or 20% of vancomycin HCl were released from 42.500 Mn or 
70.000-90.000 Mn PCL microspheres, respectively, in 24 h. No difference was 
observed in the particle size, drug-loading efficiency, morphology, in vitro 
release and antimicrobial activity of the formulations after γ-sterilization 
(p > 0.05).