Drug release test of zoledronic acid-loaded calcium sulfate in vitro

Objective To observe a drug delivery system based on calcium sulfate with the different concentrations of zoledronic acid in vitro.Methods Five concentrations of zoledronic acid were mixed with calcium sulfate and placed in distilled water.The concentration in the water was measured daily for 21 days,then the high performance liquid chromatography (HPLC) was used to observe the model of zoledronic release at different time points.Results The release of zoledronic acid was greatest during the first 24 h for all concentrations and decreased rapidly during next 24 h.The accumulated release rate of B,C,D and E was 19.11％,23.45％,35.93％ and 26.88％ respectively.The dissolution curve of the over drug-loaded groups waved seriously after 48 h.The structure of calcium sulfate was unstable with the increase of loading durgs.Conclusion Calcium sulfate is a good slow-release carrier of zoledronic within its range of maximum drug load.Zoledronic can release from calcium sulfate slowly and steay. Key words: Calcium sulfate ;  Zoledronic ;  Drug release