A drug complex characterized in that a residue of a drug compound such as antineoplastic agents and a carboxy(C
1-4
)alkyldextran polyalcohol obtained by treating a dextran under conditions that enable substantially complete polyalcoholization are bound to each other by means of a spacer comprising an amino acid or a spacer comprising peptide-bonded 2 to 8 amino acids. Said complex is characterized in that it has excellent selectivity to tumorous sites so as to exhibit high antineoplastic activity and also achieves reduced appearance of toxicity.
A drug complex characterized in that a residue of a drug compound such as antineoplastic agents and a carboxy(C1-4)alkyldextran polyalcohol obtained by treating a dextran under conditions that enable substantially complete polyalcoholization are bound to each other by means of a spacer comprising an amino acid or a spacer comprising peptide-bonded 2 to 8 amino acids. Said complex is characterized-in that it has excellent selectivity to tumorous sites so as to exhibit high antineoplastic activity and also achieves reduced appearance of toxicity.
A method for preparing a drug complex in which a polysaccharide derivative having carboxyl groups and a residue of a drug compound are bound to each other by means of a spacer comprising an amino acid or a spacer comprising peptide-bonded 2 to 8 amino acids, or a drug complex in which a polysaccharide derivative having carboxyl groups and a residue of a drug compound are bound to each other without the spacer, characterized in that an organic amine salt of the polysaccharide derivative having carboxyl groups is reacted with the drug compound or the spacer bound to the drug compound in a non-aqueous system. The reaction between the polysaccharide derivative having carboxyl groups and the drug compound bound with the spacer or the like can be carried out in high yields, and when a drug compound having a lactone ring is subjected to the reaction, side reactions can be reduced.