ENHANCED RECTAL ABSORPTION OF β-LACTAM ANTIBIOTICS IN RAT BY MONODESMOSIDES ISOLATED FROM PERICARPS OF SAPINDUS MUKUROSSI (ENMEI-HI)

Monodesmosides, saponin A, B and C, isolated from pericarps of Sapindus mukurossi(Enmei-hi) were shown to promote the rectal absorption of β-lactam antibiotics in rat, using an in situ loop method and an in vivo method. In the in situ loop method, monodesmosides were solubilized with a mixture of bisdesmosides, mukurozi-saponin X, Y_1 and Y_2,each of which was isolated from pericarps of Sapindus mukurossi. The promoting functions of the three monodesmosides for the rectal absorption of antibiotics were comparable and also suppressed by Ca^<2+> ion coexisting in the administered solution. Unlike the case of N-acylcollagenpeptides, which were also previously reported as absorption promoters, no influence of osmolarity of the administered solution on the absorption promoting action was observed. Absorption of β-lactam antibiotics from suppositories was enhanced with the aid of either of monodesmosides without solubilizing agent.