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US 6,552,198 B1Granted
Method of stabilizing aqueous pyrazoloacridone derivative solution
AssigneeKyowa Hakko Kogyo Co., Ltd.
InventorsYutaka Tomoda, Nobuhito Ashikawa, Yasuki Kato, Kunio Ito
Life of this patent
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Abstract
An aqueous solution of a pyrazoloacridone compound or pharmaceutical salt is stabilized using an acid, placing the solution in a well-closed container, evacuating air in the container, and sealing the container.
Claims16
A method for stabilizing an aqueous solution containing a pyrazoloacridone compound or a pharmaceutically acceptable salt thereof, comprising:
- adding an acid to a container of an aqueous solution comprising a pyrazoloacridone compound represented by formula (I):
- wherein R1a, R1b, R1c and R1d independently represent hydrogen, a lower alkyl group, —(CH2)p—X (wherein p is an integer of 1 to 6;
- and X represents a hydroxyl group, a lower alkoxy group, or —NR2aR2b (wherein R2a and R2b independently represent hydrogen, a lower alkyl group, —(CH2)m—Y (wherein m is an integer of 1 to 6;
- and Y represents a hydroxyl group, a lower alkoxy group, or —NR3aR3b (wherein R3a and R3b independently represent hydrogen or a lower alkyl group)), or R2a and R2b form a heterocyclic group together with the nitrogen atom adjacent thereto)), or —CH((CH2)nOH)2 (wherein n is an integer of 1 to 5) or a pharmaceutically acceptable salt thereof;
- evacuating air from the container;
- and
- sealing the container.
4 more elements
A well-closed container comprising an aqueous solution containing a pyrazoloacridone compound represented by formula (I):
- wherein R1a, R1b, R1c and R1d independently represent hydrogen, a lower alkyl group, —(CH2)p—X (wherein p is an integer of 1 to 6;
- and X represents a hydroxyl group, a lower alkoxy group, or —NR2aR2b (wherein R2a and R2b independently represent hydrogen, a lower alkyl group, —(CH2)m—Y (wherein m is an integer of 1 to 6;
- and Y represents a hydroxyl group, a lower alkoxy group, or —NR3aR3b (wherein R3a and R3b independently represent hydrogen or a lower alkyl group)), or R2a and R2b form a heterocyclic group together with the nitrogen atom adjacent thereto)), or —CH((CH2)nOH)2 (wherein n is an integer of 1 to 5), or a pharmaceutically acceptable salt thereof, and an acid,
- wherein an atmosphere in the well-closed container does not contain air.
1 more element
Dependencies are inferred from the claim text.