CROSS-LINKED ALPHA,BETA-POLYASPARTHYDRAZIDE HYDROGELS - EFFECT OF CROSS-LINKING DEGREE AND LOADING METHOD ON CYTARABINE RELEASE RATE

alpha,beta-Polyasparthydrazide (PAHy) was crosslinked by glutaraldehyd e to form water-swellable polymers possessing a three dimensional mole cular network. The glassy polymeric material was loaded with cytarabin e and shaped as micromatrices. The drug was incorporated both during c rosslinking reaction by dissolving it in the reaction medium and after crosslinking by a soaking technique. The polymer network structure wa s characterized by dimensional analysis, swelling measurements, scanni ng electron microscopy and X-ray analysis. Biological trials have show n the absence of toxicity after subcutaneous implantation of these mat erials in laboratory animals. Drug release from the micromatrices load ed by the soaking method takes place in less than 4 h. On the contrary , samples loaded during crosslinking reaction release 40% of cytarabin e in 20 days.