Preparation, characterization and release of microencapsulated bromodeoxyuridine

Biodegradable and biocompatible microspheres with bromodeoxyuridine (BrUrd) have been prepared, characterized and tested in vitro and in vivo. Scanning electron microscopy and image analysis revealed regular spherical shapes and an average size +/- SD of 2.47 +/- 0.59 microns. Total content of BrUrd as determined by HPLC was within the range of 0.2-1.5%. Kinetic analyses of two different preparations showed similar release half-times (approx. 12 hrs), kinetic constants -0.0556, -0.0564, and -0.0557, -0.0597 [h-1], and correlation coefficients of 0.998, and 0.999 when fitted to the first order or biphasic first order kinetics, respectively. Preliminary data from immunocytochemical studies revealed efficient incorporation of BrUrd delivered from these microcapsules into nuclei of proliferating cells surrounding brain lesions in rats.