Study on the yield stress measurement methods of two kinds of semi-solid preparations for external skin use
Objective:To investigate the characteristics and application scopes of three yield stress measurement methods of semi-solid preparations for external skin use to provide basis for the selection of methods for such determination.Methods:The yield stress of two kinds of semi-solid preparations for external skin use was measured by transient viscosity method,creep test method and the rheological regression method.The results were compared and analyzed by combining thixotropy characteristics,and the characteristics and application scopes of the three methods were discussed.Results:It was shown that the three gelling agents were used as simple yield stress fluids,and all three yield stress determination methods were applicable.For the three emulsions/ointments which belong to thixotropic yield stress fluids,the rheological regression method is not applicable,and the transient viscosity method has poor repeatability.The creep test method can accurately measure the yield stress of the above two kinds of semi-solid preparations for external skin use.Conclusion:The yield stress measurement method for semi-solid preparations can be selected based on the preparation properties,method characteristics and application scenarios.