A process for manufacturing a solution of a compound of formula II: or its pharmaceutically acceptable salt, hydrate or solvate; wherein, R 1 is 1-hydroxyethyl, 1-fluoroethyl, or hydroxymethyl; R 2 and R 3 are independently hydrogen, or C 1 -C 6 alkyl; R 4 and R 5 are independently hydrogen, C 1 -C 6 alkyl, or alkali-metal or alkali earth-metal wherein the alkali-metal or alkali earth-metal is sodium, potassium, lithium, cesium, rubidium, barium, calcium or magnesium; R 6 and R 7 are independently hydrogen, halo, cyano, nitro, hydroxy, carboxy, amino, C 1 -C 6 alkylamino, di C 1 -C 6 alkylamino, C 1 -C 6 alkoxy, C 1 -C 6 alkoxycarbonyl, aminosulphonyl, C 1 -C 6 alkylaminosulphonyl, di- C 1 -C 6 alkylaminosulphonyl, carbamoyl, C 1 -C 6 alkylcarbamoyl, trifluoromethyl, sulphonic acid, C 1 -C 6 alkanoylamino, C 1 -C 6 alkanoyl(N-(C 1 -C 6)-alkyl)amino, C 1 -C 6 alkanesulphonamido, C 1 -C 6 alkyl-S n wherein n is 0-2; and R 8 is independently hydrogen, sodium, potassium, lithium, cesium, barium, rubidium, calcium or magnesium; from a solution of a compound of formula I: or its pharmaceutically acceptable salt, hydrate or solvate; wherein, R 1, R 2, R 3, R 4, R 5, R 6 and R 7 are as defined in the compound of formula II; characterized in that the method comprises the steps of: (a) dissolving a carbonate source and a base in a diluent to form a first solution at a temperature from 0°C to 25°C, wherein a mole ratio of the carbonate source to the compound of formula I is 0.5 to 1.5, and a mole ratio of the base to the compound of formula I is 0.7 to 1.0; (b) mixing the compound of formula I with the first solution at a temperature from -5°C to 25°C to form the solution without making actions to maintain pH of the solution of the compound of formula I. R 1 is 1-hydroxyethyl, 1-fluoroethyl, or hydroxymethyl; R 2 and R 3 are independently hydrogen, or C 1 -C 6 alkyl; R 4 and R 5 are independently hydrogen, C 1 -C 6 alkyl, or alkali-metal or alkali earth-metal wherein the alkali-metal or alkali earth-metal is sodium, potassium, lithium, cesium, rubidium, barium, calcium or magnesium; R 6 and R 7 are independently hydrogen, halo, cyano, nitro, hydroxy, carboxy, amino, C 1 -C 6 alkylamino, di C 1 -C 6 alkylamino, C 1 -C 6 alkoxy, C 1 -C 6 alkoxycarbonyl, aminosulphonyl, C 1 -C 6 alkylaminosulphonyl, di- C 1 -C 6 alkylaminosulphonyl, carbamoyl, C 1 -C 6 alkylcarbamoyl, trifluoromethyl, sulphonic acid, C 1 -C 6 alkanoylamino, C 1 -C 6 alkanoyl(N-(C 1 -C 6)-alkyl)amino, C 1 -C 6 alkanesulphonamido, C 1 -C 6 alkyl-S n wherein n is 0-2; and R 8 is independently hydrogen, sodium, potassium, lithium, cesium, barium, rubidium, calcium or magnesium; from a solution of a compound of formula I: or its pharmaceutically acceptable salt, hydrate or solvate; wherein, R 1, R 2, R 3, R 4, R 5, R 6 and R 7 are as defined in the compound of formula II; characterized in that the method comprises the steps of: (a) dissolving a carbonate source and a base in a diluent to form a first solution at a temperature from 0°C to 25°C, wherein a mole ratio of the carbonate source to the compound of formula I is 0.5 to 1.5, and a mole ratio of the base to the compound of formula I is 0.7 to 1.0; (b) mixing the compound of formula I with the first solution at a temperature from -5°C to 25°C to form the solution without making actions to maintain pH of the solution of the compound of formula I. from a solution of a compound of formula I: or its pharmaceutically acceptable salt, hydrate or solvate; wherein, R 1, R 2, R 3, R 4, R 5, R 6 and R 7 are as defined in the compound of formula II; characterized in that the method comprises the steps of: (a) dissolving a carbonate source and a base in a diluent to form a first solution at a temperature from 0°C to 25°C, wherein a mole ratio of the carbonate source to the compound of formula I is 0.5 to 1.5, and a mole ratio of the base to the compound of formula I is 0.7 to 1.0; (b) mixing the compound of formula I with the first solution at a temperature from -5°C to 25°C to form the solution without making actions to maintain pH of the solution of the compound of formula I. (a) dissolving a carbonate source and a base in a diluent to form a first solution at a temperature from 0°C to 25°C, wherein a mole ratio of the carbonate source to the compound of formula I is 0.5 to 1.5, and a mole ratio of the base to the compound of formula I is 0.7 to 1.0; (b) mixing the compound of formula I with the first solution at a temperature from -5°C to 25°C to form the solution without making actions to maintain pH of the solution of the compound of formula I.