A pharmacy technician receives a prescription for insulin with instructions to inject 45 units daily for 28 days. The pharmacy stocks 10mL vials that have a concentration of 300 units/mL. How many vials should the technician plan to dispense?

To determine how many vials of insulin to dispense, it is important to first calculate the total amount of insulin needed for the entire duration of treatment.

The prescription indicates that the patient needs to inject 45 units daily for 28 days. Therefore, the total dosage required can be calculated as follows:

Total units needed = 45 units/day × 28 days = 1260 units.

Next, the concentration of the insulin available in the pharmacy is 300 units/mL. To find out how many milliliters are needed to dispense 1260 units of insulin, the calculation is as follows:

Total mL needed = Total units needed / Concentration = 1260 units / 300 units/mL = 4.2 mL.

Since the insulin comes in 10 mL vials, and the technician will be dispending just over 4 mL, one vial will be more than sufficient to cover the full requirement of 4.2 mL. Therefore, it is appropriate to dispense just one vial, making it the correct answer.

The significant details lie in the fact that each vial contains enough units to meet the demand of the prescription over the 28-day period without needing more than one vial.