Abstract
In Japan, wood creosote pills containing four herbal drugs have been used to treat food poisoning and diarrhea. It was previously reported that among the four herbal drugs used, Citri Unshiu Pericarpium (CUP2, Chinpi in Japanese) plays an important role in sustaining the dissolution of the active constituents of wood creosote (guaiacol) from the pill. To clarify the pharmaceutical role of CUP2 in these pill, pharmacokinetic interactions between CUP2 and guaiacol were examined after oral administration of a wood creosote pill containing four herbal drugs (P4R) to rats. The mean residence time (MRT) of guaiacol in the P4R-treated rats was significantly longer than that of the rats treated with a variant pill (P4R with a reduced amount or without CUP2). There were no significant differences in the area under the mean concentration versus time curve from zero to 5 h (AUC 0-5 h) between the two groups. The prolongation effect of CUP2 on the MRT of guaiacol was thought to be partly due to the mean dissolution time (MDT) of guaiacol from the pill. Since a long MRT and MDT are indexes of the duration effects of drugs, CUP2 might be a good adjuvant for prolonging anti-diarrhea effects after oral administrations of wood creosote pills.
