| abstract |
[Chemical 1] A compound of formula (I) wherein A is a C alkylene group having a chain length of at least two carbon atoms between NH and N (O) R′R ″, wherein R ′ and R ″ are , C 1-4 alkyl group, and C 2-4 hydroxyalkyl group and C 2-4 dihydroxyalkyl group, or R ′ and R ″ are both C 2-6 alkylene groups. When dissolved in an aqueous solution, the pH of the solution is 5 to 9. This compound is physiologically acceptable with a pKa of −3.0 (minus 3.0) to 9.0. In the form of a salt with an acid. |