The aim of this study was to evaluate the effects of
emulsion type and process parameters on the properties of CPX-loaded PLGA
microspheres in order to obtain delivery systems suitable for the treatment of dairy
mastitis. The
microsphere size was analyzed by photon correlation spectrophotometry. Determination of the
drug loading was achieved by HPLC. It was found that CPX-loaded PLGA
microspheres prepared using a w/o/w double
emulsion technology were slightly larger (approximately 3-5 microm) but much higher in
drug content (approximately 18% w/w) than those obtained using o/w single
emulsion preparation technology (average size was 2 microm, encapsulation efficiency was less than 2 %). It was also demonstrated that stirring during emulsification and a change in both the internal and external phase of the
emulsion, affected the size and the
drug entrapment efficiency of the
microspheres obtained. A 60/40 v/v mixture of
chloroform and
acetone was found to be the best organic
solvent system for creating the primary
emulsion. To obtain a high yield (>90%) of
microspheres with a desirable size and high
drug entrapment efficacy, a stirring rate of 8,000-10,000 rpm gave the best results. It is concluded CPX-loaded PLGA
microspheres with suitable characteristics for the treatment of cows with dairy
mastitis can be prepared by a w/o/w double
emulsion preparation method.