PROGESTERONE-LOADED ALBUMIN MICROPARTICLES

Bovine serum albumin (BSA) was used to prepare microspheres and microc apsules containing progesterone. The microparticles were obtained by m eans of a multiple emulsion method and by thermal or chemical crosslin king. The drug loading was higher for microspheres than microcapsules and varied for the different crosslinking methods: higher with thermal than chemical crosslinking and, among the chemical crosslinkers, load ing was higher for formaldehyde than 2,3-butanedione and glutaraldehyd e, respectively. Drug release was well differentiated for the differen t systems: the microspheres released 60% of their content according to an anomalous diffusion mechanism in the shorter periods, whereas micr ocapsules released 60% of their content according to different kinetic trends and for longer periods of time. The duration of each kinetic p eriod and the relative drug fraction released, depends on the crosslin king method (thermal or chemical) and the nature of the crosslinking a gent. Among the systems examined, the glutaraldehyde crosslinked micro spheres show the higher release rate while the thermally crosslinked m icrocapsules had the lowest release rate which is characterized by the longest lasting zero order period.