For a subcutaneous administration of 400,000 units from a stock concentration of 250,000 units/mL, how many milliliters should be drawn?

To determine how many milliliters should be drawn for a subcutaneous administration from a stock concentration, you can use the formula:

[ \text{Volume (mL)} = \frac{\text{Desired Dose (units)}}{\text{Concentration (units/mL)}} ]

In this scenario, you need to administer 400,000 units and the stock concentration is 250,000 units/mL. Plugging in the numbers:

[ \text{Volume (mL)} = \frac{400,000 \text{ units}}{250,000 \text{ units/mL}} = 1.6 \text{ mL} ]

This calculation shows that to achieve a dose of 400,000 units from a concentration of 250,000 units/mL, you must draw 1.6 mL from the stock. Understanding this calculation is crucial for correct dosing in pharmacology, as accurate administration affects therapeutic outcomes. It’s essential to ensure that the required volume is administered properly to avoid underdosing or overdosing, which can lead to ineffective treatment or increased risk of side effects.