You're not required by most airlines to have the Vitamins in the original bottles when flying but it would be best to keep the vitamins in the original bottles anyway so that the medications and vitamins do not get mixed up.
There's no limit to the amount of Vitamins or other medications that are allowed in your carry on luggage either so you can take as much Vitamins and other medications that you need with you onboard the airplane.
Liquid medication though is limited to 3.4 ounces for carry on luggage but there's no limit to the amount of liquid medication that you may carry on the plane itself.