if I pre make bottles

If I pre make bottles of formula using powder and put it in the fridge, when I take it out how long can it sit out. I'll be using powder probably tomorrow but now I have the premade bottles so I take 3 of those upstairs with me for his feedings so I don't have to come back down stairs each time. So would it be okay to make powdered formula in the morning, put it in the fridge and take the bottles out when we go up to bed. I feed him at 9 then usually go up to bed so around 9:30-10. He'd have a bottle at 12, 3&6.