Possible Mechanism Behind the Adjuvant Action of Phosphate Derivatives on Rectal Absorption of Cefoxitin in Rats and Dogs

Enzymatic Barriers to Peptide and Protein Absorption and the Use of Penetration Enhancers to Modify Absorption

“…Interestingly, weak adjuvants which are so by virtue of their inability to penetrate membranes, such as tripfrlyphosphate and phytate, have been found to improve upon their potency significantly in the presence of an intrinsically potent enhancer, in this instance, a-glycerophosphate (Nishihata et al, 1984b), as shown in Table 6. The coadministration of monoolein and bile salt has also been found to bring about a synergistic effect in enhancing the oral absorption of heparin in the rat (Table 7), presumably due to facilitation of membrane penetration of the bile salt by monoolein (Taniguchi et al, 1980).…”

“…As reported by Kamada et al (1981), in a series of phenyl alanyl enamine type enhancers, which act by chela- Table 6. Effect of Co-Adjuvants on Rectal Absorption of Cefoxitin (Nishihata et al, 1984b) mmoles/body % Bioavailability a-Glycerophosphate Tripolyphosphate Phytate Fig. 6.…”