Isostatic compression, a new process for incorporating vancomycin into biphasic calcium phosphate: comparison with a classical method

Isostatic compression has rarely been used to load calcium-phosphate biomat erials with therapeutic agents. This report, concerning four processes asso ciating vancomycin, compares isostatic compression with wet granulation, a classical method. In the wet granulation study, vancomycin was associated w ith biphasic calcium-phosphate (BCP) granules either by adsorption or incor poration with a new granulation. In the isostatic compression study, BCP po wder was compressed at 100, 140 and 200 MPa. The blocks obtained were crush ed and 200-500 mu m, sieved; thus, the vancomycin solution was absorbed on these granules. Compaction of BCP and vancomycin powders gave, after crushi ng and sieving, granules loaded with vancomycin. In each study, 5% vancomyc in was associated with BCP. Vancomycin release profiles were assessed by an in vitro culture chamber dissolution test. Physicochemical studies of BCP and vancomycin showed their structural integrity after isostatic compressio n. Isostatic compression prolonged vancomycin release time from 3 to 7 days and the release time became greater as isostatic pressure increased, proba bly because of the porosity decrease of the granules during compression. (C ) 2000 Elsevier Science Ltd. All rights reserved.