NAPHTHYRIDINIUM DERIVATIVE

PURPOSE:To obtain a new derivative useful for diagnosing and evaluating the pharmacodynamic effects on diabetes (complications), complication related to dialysis and senescence (diseases caused thereby), etc. CONSTITUTION:This derivative (salt) is expressed by the formula [R and R' are each a (protecting group-containing)amino or a (carboxyl group-containing) alkyl], e.g. a 1,7-bis[6-(N-acetyl-L-norleucyl)]-5-(1,2,3,4-tetrahydroxybutyl)-1,4- dihydro-4-oxo-1,7-naphthyridinium salt. The derivative is usually obtained by reacting, e.g. a compound of the formula, R-NH2 or the formula, R'-NH2 with saccharides such as a hexose, e.g. glucose, a heptose, e.g. sedoheptulose, an aminosugar, e.g. glucosamine and an oligosaccharide, e.g. saccharose at ambient temperature (preferably under heating conditions).