PREPARATION AND CHARACTERIZATION OF ALBUMIN-HEPARIN MICROSPHERES

Albumin-heparin microspheres were prepared by a two-step process which involved the preparation of a soluble albumin-heparin conjugate, foll owed by formation of microspheres from this conjugate or by a double c ross-linking technique involving both coupling of soluble albumin and heparin and microsphere stabilization in one step. The first technique was superior since it allowed better control over the composition and the homogeneity of the microspheres. Microspheres could be prepared w ith a diameter of 5-35 mu m. The size could be controlled by adjusting the emulsification conditions. The degree of swelling of the microsph eres was sensitive to external stimuli, and increased with increasing pH and decreasing ionic strength of the medium.