between 0 002 and 10 mg ml and more preferably between 0 002 mg ml and the limits of solubility of the folate compound in any particular carrier the concentration of niacinamide will be 100 times this amount the vitamin b12 concentration will be in the range 0 1 mg ml to the limits of solubility of the vitamin the topical composition can be reapplied periodically during sun exposure to replace removed or absorbed material if the three b complex vitamins are administered orally the composition in a suitable carrier can be administered in single unit dosage form with continuous therapy or in single dose therapy ad libitum the composition could be administered in the form of tablets pills capsules powders enterically coated or other protected formulations such as binding on ion exchange resins or other carriers or packaging in lipid protein vesicles or adding additional terminal amino acids sustained release formulations solutions e g ophthalmic drops suspensions elixirs aerosols and the like the compositions could also be administered orally or sublingually or in the form of a juice or other suitable drink or other suitable dietetic composition the particular dosage of pharmaceutical composition to be administered to the subject orally parenterally enterally entranasally rectally or ocularly will depend on a variety of considerations including the schedule of administration the age and physical characteristics of the subject and so forth the pharmaceutical compositions to be administered orally parenterally enterally entranasally rectally or.