Storage liquid for mammalian cells

A platelet which is preserved in a preservation solution having the following features i) and ii):

• i) the preservation solution comprising 10 to 5000 mg/L of niacin or a salt of niacin, and 10 to 8000 mg/L of ascorbic acid or a salt of ascorbic acid, and having an osmotic pressure that is isotonic with the platelet;
• ii) the preservation solution being kept neutral when the preservation solution has been preserved under horizontal shaking at 50 rpm and at 22° C. for 10 days in the dark, in a state of being contained in a blood preservation bag with the platelet at a platelet concentration of 1.0×109 plts/mL.

A platelet formulation which is preserved in a preservation solution having the following features i) and ii):

• i) the preservation solution comprising 10 to 5000 mg/L of niacin or a salt of niacin, and 10 to 8000 mg/L of ascorbic acid or a salt of ascorbic acid, and having an osmotic pressure that is isotonic with the platelet;
• ii) the preservation solution being kept neutral when the preservation solution has been preserved under horizontal shaking at 50 rpm and at 22° C. for 10 days in the dark, in a state of being contained in a blood preservation bag with the platelet at a platelet concentration of 1.0×109 plts/mL.

A preservation solution for preserving a platelet, the preservation solution comprising 10 to 5000 mg/L of niacin or a salt of niacin, and 10 to 8000 mg/L of ascorbic acid or a salt of ascorbic acid, and having an osmotic pressure that is isotonic with the platelet, wherein the preservation solution is kept neutral when the platelet has been preserved under horizontal shaking at 50 rpm and at 22° C. for 10 days in the dark, in a state of being packed in a blood preservation bag with the preservation solution at a platelet concentration of 1.0×109 plts/mL.

A platelet preserved in a preservation solution, wherein the preservation solution is for preserving the platelet at 20 to 24° C. for 1 to 15 days, the preservation solution comprising 10 to 5000 mg/L of niacin or a salt of niacin, and 10 to 8000 mg/L of ascorbic acid or a salt of ascorbic acid, and not comprising vitamin B2 or a salt of vitamin B2.

A platelet formulation preserved in a preservation solution, wherein the preservation solution is for preserving the platelet at 20 to 24° C. for 1 to 15 days, the preservation solution comprising in an isotonic solution 10 to 5000 mg/L of niacin or a salt of niacin, and 10 to 8000 mg/L of ascorbic acid or a salt of ascorbic acid, and not comprising vitamin B2 or a salt of vitamin B2.

A method for preserving a platelet, comprising the step of preserving the platelet in a preservation solution comprising 10 to 5000 mg/L of niacin or a salt of niacin, and 10 to 8000 mg/L of ascorbic acid or a salt of ascorbic acid, and having an osmotic pressure that is isotonic with the platelet, wherein the preservation solution is kept neutral, the platelet has been preserved under horizontal shaking at 50 rpm and at 22° C. for 10 days in the dark, in a state of being packed in a blood preservation bag with the preservation solution at a platelet concentration of 1.0×109 plts/mL.