Patent ID: 8871818

Claim:
A method for using a pH-sensitive polymer comprising: measuring a pH at which a peptide transporter 1 optimally transports a compound recognized by the peptide transporter 1 into a cell, mixing the compound and the pH-sensitive polymer, and adjusting a pH of a small intestinal tract to the previously measured pH by introducing the mixture to the small intestinal tract, thereby enhancing small intestinal absorbability of the compound wherein the pH-sensitive polymer is at least one member selected from the group consisting of dried methacrylic acid copolymer, methacrylic acid copolymer LD, methacrylic acid copolymer L, methacrylic acid copolymer S, polyacrylic acid, maleic acid/n-alkyl vinyl ether copolymer, hydroxypropylmethylcellulose acetate succinate, and hydroxypropylmethylcellulose phthalate, and wherein the amount of the pH-sensitive polymer is about 50 to about 1000 parts by weight per part by weight of the compound recognized by the peptide transporter 1.