Improvement of dissolution rate for valsartan using melt-adsorption method with supercritical carbon dioxide

다국어 초록 (Multilingual Abstract)

The aim of this thesis was to improve of dissolution rate for valsartan using melt-adsorption method using supercritical carbon dioxide. Valsartan, poorly water soluble drug, is used for controlling high blood pressure and angiotensin Ⅱ receptor antagonist that acts on the AT1 subtype. In this study, valsartan loaded mesoporous silica was prepared using supercritical carbon dioxide to improve dissolution rate of valsartan. For determination of operating condition of supercritical process, phase behavior study including melting point depression study was conducted. The melting point of valsartan was significantly decreased in compressed carbon dioxide. In the supercritical adsorption process by varying the ratio of valsartan with the porous adsorbent has confirmed that the optimum ratio, supercritical adsorption process was more effective than other adsorption processes and was confirmed through various experiments. Based on data of phase behavior study of valsartan, supercritical process was optimized using factorial design. Temperature and pressure were used as independent variables. The total pore volume, crystallinity and dissolution efficiency were used as dependent variables for evaluation of valsartan loaded mesoporous silica. As a result, the lower the temperature, the more pressure is increased valsartan is adsorbed evenly inside the pores in the porous adsorbent. The total pore volume and crystallinity were decreased and dissolution rate was increased. . From optimization study, it is appeared that the optimization condition is 40℃ and 12 MPa. Therefore, result from this study suggested that supercritical adsorption process was more effective than other adsorption process and improve the dissolution rate of valsartan.