that depends on the liquid
in water it would be (5ng)/mg because 1ml=1mg for water
Chat with our AI personalities
This is not a valid conversion; milligrams (mg) and grams (g) are measures of weight or mass and mL (milliliters) is a measure of volume.
You have to give 3 times 5 mg = 15 mg therefore you have to give 3 times 2 ml = 6 ml (15 mg = 6 ml of whatever that bottle contains).
It looks like the 3.5 ml may be extraneous information. If 1 ml yields 250 mg, then you need 400/250 = 1.6 ml, to get 400 mg.
2 mg per 1 ml is more concentrated but that means that you will need a bigger quantity of the 0.2 mg per 1 ml mixture for the same amount of the active ingredient.
It is not possible to answer this without knowing the density of the active ingredient per ml. I.e some drugs may be 1000mg per ml, whereas others could be 2mg per ml. There is no standard "amount per ml" for all liquid medicines etc...