It depends on the density (mass per unit volume). A milligram (mg) is a measure of mass, a cubic centimeter (cc) is a measure of volume. Different materials have different densities, and so will have different numbers of milligrams per cubic centimeter.
Sometimes a question like this arises in relation to drug dosage. To answer your question in that context, you need to know the concentration of the drug in its solution.
Sometimes a question like this arises in relation to drug dosage. To answer your question in that context, you need to know the concentration of the drug in its solution.