It is impossible to directly translate 50 mcg to mL without the concentration of the substance (mcg/mL). Once you have that, divide 50 mcg/concentration to obtain the mL value.
It is not possible to directly relate the mass of the substance (mcg) to the volume (mL) without the concentration of that substance. To determine it, you will require information such as 50 mcg/mL or the strength of a medication (ex: 100 mcg/mL).
