Evaluation of process parameters involved in chitosan microsphere preparation by the O/W/O multiple emulsion method.

In this work, an o/w/o multiple emulsion technique was used to prepare hydrophobic drug loaded chitosan microsphers. Moreover, the influence of different viariables (acetic acid concentration and drug/polymer ratio) on microspheres morphology and drug content was evaluated. Two chitosans of different molecular weight and degree of deacetylation were used; ketoprofen, an anti-inflammatory drug, was chosen as model hydrophobic drug. The new pretaration method produced well-formed microspheres with very good yields. Acetic acid concentration influenced particle sizes and drug content of the microspheres. The highest drug encapsulation efficiency was achieved with the lowest theoretical drug/chitosan ratio.