Adding diluent to liquid drugs to create desired concentrations
Drug A, is available as 40 mg/mL. You need to make 100 mL of a 10 mg/mL solution. How much starting solution do you need? How much diluent?
Starting Solution = 100 mL - ((100 mL x 10 mg/mL) x (1 / 40 mg/mL))
Starting Solution = 100 mL - (1000 mg x (1 / 40 mg/mL))
Starting Solution = 100 mL - (1000 mg / 40 mg/mL)
Starting Solution = 100 mL - 25 mL
Starting Solution = 75 mL
Amount of Diluent = 100 mL - 75 mL
Amount of Diluent = 25 mL
Drug A is available as 60 mL of 120 mg/mL. You need to make a 30 mg/mL solution using the whole bottle. How much diluent will you need? What is the volume of the new bottle?
Amount of diluent = (60 mL x 120 mg/mL) x (1 / 30 mg/mL)
Amount of diluent = 7200 mL * (1 / 30 mg/mL)
Amount of diluent = 7200 mL / 30 mg/mL
Amount of diluent = 240 mL
New Volume = 240 mL + 60 mL
New Volume = 300 mL
You have created 50 mL of a diluted solution with a concentration of 25 mg/mL. You used 10 mL of Drug A. What was the original concentration of Drug A?
Original Concentration = (50 mL * 25 mg/mL) / 10 mL
Original Concentration = (1250 mg) / 10 mL
Original Concentration = 125 mg/mL