PREPARATION AND CHARACTERIZATION OF CA-ALGINATE MICROSPHERES BY A NEWEMULSIFICATION METHOD

The preparation and characterization of Ca-alginate microspheres obtai ned by a new procedure from alginic acid, treated with an excess of Na OH and subsequently with a very concentrated solution of CaCl2 are des cribed. The produced particles have a spherical shape with an average diameter of 350 mu m. The particles show a relative dense and homogene ous internal structure in comparison with previously reported alginate microcapsules (the bulk density being 0.47 g/cm(3)), consequently the particle matrix is characterized by a high density of charged carboxy lic groups. Particles produced with a contact time of 1 h showed a deg ree of crosslinking of 54%. Microspheres have a good stability, and de spite of very low degree of swelling, they have a good solvents regain , and an excellent ionic binding capacity of cationic drugs. After pre paration the beads were loaded by ionic complexation with an antitumor aromatic tetramidine. In addition, the in vitro release of drug has b een studied. (C) 1998 Elsevier Science B.V. All rights reserved.