EVALUATION OF PROCESS PARAMETERS INVOLVED IN CHITOSAN MICROSPHERE PREPARATION BY THE O W/O MULTIPLE EMULSION METHOD/

Chitosans are interesting biopolymers largely studied for applications in the medical and pharmaceutical fields. In this work, an o/w/o mult iple emulsion technique was used for the preparation of hydrophobic dr ug loaded microspheres. Moreover, the influence of critical variables (concentration of acetic acid in the polymer solution and drug-polymer ratio) on microsphere morphology and drug content was evaluated. Two chitosans of different molecular weights and deacetylation degree were employed; ketoprofen, a non-steroidal antiinflammatory drug, was chos en as the hydrophobic model drug. The multiple emulsion method produce d well-formed microspheres with good yields. Acetic acid concentration in the polymeric solutions influenced particle size and drug content of the microspheres. The highest drug encapsulation efficiencies were obtained for the lowest theoretical drug/chitosan ratio.