Physicochemical Studies on Decoctions of Kampo Prescriptions. I. Transfer of Crude Drug Components into the Decoctions

Abstract

To evaluate the profile of the crude drug components transferred into the decoction, decoctions of about 30 kampo prescriptions, comprising 13 quantitatively assayable crude drugs, were prepared; the quantities (mg/daily dose) and ratios (%) of these components transferred from the drug into the decoctions were determined by HPLC. Then, a chromatographic substitute for the hydrophobic parameter was determined in various crude drug components, and its relationship with the quantities and ratios transferred was examined. The transfer of stable crude drug components into the decoctions was found to be regulated by the hydrophobicity of the components, which is related to their transfer ratio, rather than the amount transferred. In addition, the transfer ratio and the value of the hydrophobic parameter did not exhibit a simple linear relationship.