Patent ID: 7897772

Claim:
A method for producing an irinotecan acid addition salt with an acid selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid, methanesulfonic acid, citric acid, maleic acid, and succinic acid to irinotecan, the method comprising suspending irinotecan in a lower alcohol, water, or an aqueous lower alcohol, to thereby form a suspension; subsequently, adding to the suspension an acid selected from the group consisting of sulfuric acid, nitric acid, phosphoric acid, methanesulfonic acid, citric acid, maleic acid, and succinic acid, to thereby form a mixture; and subsequently, adding acetonitrile, acetone, or an acetonitrile-acetone mixed solvent to the mixture, to thereby crystallize the salt, or lyophilizing the mixture.