Powdered Drug Preparations

26. 10 million units of a powdered antibiotic are contained in a vial. A concern of 500,00 units per mL is obtained when sterile water for injection is added. The drug has a powder volume of 3.2mL. How many mL of sterile water for injection should be added to the vial?

(500,000units/1mL) = (10,000,000units/x) x = 20mL = FV DA = 20mL - 3.2mL DA = 16.8mL

19. A technician adds 64 mL of sterile water for injection to a pharmacy bulk bottle of 30g of antibiotic powder. The antibiotic has the power volume of 6mL. Calculate the concentration, in mg/mL, obtained after reconstitution.

30 g = 30,000 mg FV = 64 ml + 6 ml = 70 ml (30,000 mg/70 ml) = 429 mg/ml

5. The directions for a vial containing 500mg of powder Rocephin state that the addition of 1.8 mL of sterile water for injection will yield a solution containing 250mg/mL. What is the powder volume of the drug?

250mg/1mL = 500mg/x (x)(250mg) = (1mL)(500mg) x = 2mL = FV PV = FV - DA PV = 2mL - 1.8mL PV = 0.2mL = answer

39. A physician orders for a patient 8MU of a drug in 100mL of 0.9% sodium chloride solution. The drug is available as a 20MU powder for reconstitution wig sterile water for injection. The instructions are to add 32mL of SWFI to obtain a concentration of 500,000 units/mL. Hint: 8MU is an abbreviation for 8 million units. a) What is the powder volume of the drug? b) How many mL of the reconstituted solution will the patient need?

a) 20MU = 20,000,000units (500,000units/1mL) = (20,000,000units/x) x = 40mL = FV PV = FV - DA PV = 40mL - 32mL PV = 8mL b) (500,000units/1mL) = (8,000,000units/x) x = 16mL

22. An 8g vial of a powdered drug requires the addition of 9.8mL of sterile water for injection to obtain a concentration of 800mg/mL. a) What is the powder volume of the drug? b) If 2.6mL of the reconstituted solution is added to a 500mL bag of D5W, what dose (in g) will the patient receive?

a) 8g = 8000mg (800mg/1mL) = (8000mg/x) x = 10mL = FV PV = Final Volume - DA PV = 10 ml - 9.8 ml PV = 0.2 ml b) (10mL/2.6mL) = (8g/x) x = 2.1g

17. A 1.5g vial of antibiotic has a powder volume of 1.4mL. You need a concentration of 125mg/mL. How many mL of sterile water for injection will you need to add to obtain this concentration?

1.5g = 1500mg (125mg/1 mL) = (1500mg/x) x = 12mL = FV 12mL - 1.4mL = 10.6mL 10.6mL = answer

1. If 95mL of sterile water for injection is added to a 10g bulk powdered drug pharmacy container, the concentration obtained is 100mg/mL. What is the powder volume of the drug?

100mg/1mL = 10,000mg/x (x)(100mg) = (1mL)(10,000mg) x = 100mL = FV PV = FV - DA PV = 100mL - 95mL PV = 5mL = answer

38. A drug concentration of 250mg/mL is needed. The powdered drug is available in a 10g vial with a powder volume of 2.4mL. How many mL of sterile water for injection should be added to the vial to obtain the needed concentration?

10g = 10,000mg (250mg/1mL) = (10,000mg/x) x = 40mL DA = 40mL - 2.4mL DA = 37.6mL

11. 10mL of sterile water for injection is added to a 1g vial of Mefoxin, giving a 10.5mL final volume. What is the concentration of the reconstituted powdered Mefoxin?

1g = 1000mg 1000mg/10.5mL = 95.2mg/mL 95.2mg/mL = answer

18. Calculate the concentration, in mg/mL, after reconstitution with 19mL of sterile water for injection, of a 2.75g vial, if the drug has a powder volume of 2.2mL.

2.75g = 2,750mg FV = 19ml + 2.2ml = 21.2ml (2750mg/21.2ml) = 129.7 mg/ml

2. Using another 10g vial of the drug in question 1, you want to concentration of 200mg/mL. How many mL of sterile water for injection should be added? (Use the powder volume calculated in question 1.).

200mg/1mL = 10,000mg/x (x)(200mg) = (1mL)(10,000mg) x = 50mL = FV DA = FV - PV DA = 50mL - 5mL DA = 45mL = answer

3. The package directions for a medication instruct you to add 4.2mL sterile water for injection to 1g of dry powder to give a concentration of 200 mg/mL. What is the powder volume of the medication?

200mg/1mL = 1000mg/x (x)(200mg) = (1mL)(1000mg) x = 5mL = FV PV = FV - DA PV = 5mL - 4.2mL PV = 0.8mL = answer

14. A 20g vial of a powdered drug requires the addition of 36mL of sterile water for injection to give a concentration of 500mg/mL. What is the powder volume of the drug?

20g = 20,000mg 500mg/1mL = 20,000mg/x (x)(500mg) = (1mL)(20,000mg) x = 40mL = FV PV = 40mL - 36mL PV = 4mL = answer

15. Using another 20g vial of the drug in question 14, you need a concentration of 400mg/mL. How many mL of sterile water for injection do you need to add to the vial?

20g = 20000mg (400mg/1mL) = (20,000mg/x) x = 50mL = FV DA = 50 mL - 4 mL DA = 46 mL

10. The directions for reconstitution for a 2g vial of Claforan state to add 10mL of sterile water for injection to obtain a concentration of 180mg/mL. What is the final volume obtained after reconstitution?

2g = 2000mg 180mg/1mL = 2000mg/x (x)(180mg) = (1mL)(2000mg) x = 11mL = FV = answer

9. To prepare 3g of Unasyn, the package insert states to add 6.4mL of diluent. The concentration obtained is 375mg/mL. What is the powder volume of the Unasyn?

3g = 3000mg 375mg/1mL = 300mg/x x = 8mL = FV (x)(375mg) = (1mL)(300mg) PV = FV - DA PV = 8mL - 6.4mL = 1.6mL 1.6mL = PV

32. What is the powder volume of 40g of a drug if after adding 89.6mL of sterile water for inject the concentration obtained is 400mg/mL?

40g = 40,000mg (400mg/1mL) = (40,000mg/x) x = 100mL = FV PV = 100mL - 89.6mL PV = 10.4mL

16. After adding 20mL of sterile water for injection to a 4g vial of powdered drug, the concentration is 325mg/2 mL. What is the powder volume of the drug?

4g = 4000mg (325mg/2mL) = (4000mg/x) x = 24.6mL = FV PV = 24.6mL - 20mL PV = 4.6mL

4. You have a vial of penicillin G potassium containing 20 million units. The directions are to add 32mL of sterile water for injection to reconstitute to a concentration of 500,000units/mL. What is the powder volume of the penicillin?

500,000units/1mL = 20,000,000units/x (x)(500,000units) = (1mL)(20,000,000units) x = 40mL = FV PV = FV - DA PV = 40mL - 32mL PV = 8mL = answer

20. If you need a concentration of 250mg/mL and you have on hand a 5g vial of antibiotic with a powder volume of 1.6mL, how many mL of sterile water for injection should you add?

5g = 5000mg (250mg/1mL) = (5000mg/x) x = 20mL = FV DA = 20mL - 1.6mL DA = 18.4mL

34. A 9g vial of powdered medication is reconstituted with sterile water for injection to a concentration of 300mg/mL. How many mL of SWFI should be added if the powder volume of the drug is 1.3mL?

9g = 9000mg (300mg/1mL) = (9000mg/x) x = 30mL = FV DA = 30mL - 1.3mL DA = 28.7mL

Remember !!!

DA = diligent added PV = powdered volume FV = final volume ( ) parentheses = times (multiply)

43. 3mL of an antibiotic is added to a 50mL IVPB. Then 5g of the medication (powder volume = 0.7mL) is reconstituted with 9.3mL of sterile water for injection. How many g of the medication was added to the IVPB?

FV = 0.7mL + 9.3mL FV = 10mL (5g/10mL) = (x/3mL) x = 1.5g

42. If 0.9mL of sterile water for injection is added to a vial containing 0.2mg of medication with a powder volume of 0.1mL, what is the final concentration in mcg/mL?

FV = 0.9 ml + 0.1 ml = 1 ml 0.2 mg/1 ml = 0.2 mg 0.2 mg x 1,000 mcg = 200 mcg/ml

30. 1mL of sterile water for injection is added to a 1.5mg vial of a powdered drug with a powder volume of 0.2mL. What is the concentration in mg/mL of the solution obtained?

FV = 1 ml + 0.2 ml = 1.2 ml 1.5 mg/1.2 ml = 1.25 mg/ml

25. A 2g vial of a powdered drug is reconstituted with 100mL of sterile water for injection. The drug has a powder volume of 2.3mL. What is the concentration of the reconstituted solution?

FV = 100 ml + 2.3 ml = 102.3 ml 2G = 2,000mg (2,000 mg/102.3 ml) = 19.6 mg/ml

7. You add 10mL of sterile water for injection to 1g of a drug that has a powder volume of 0.8mL. What is the concentration of the drug in mg/mL in the final solution.

FV = 10mL + 0.8mL = 10.8mL 1g = 1000mg 1000mg / 10.8mL = 92.6mg/mL 92.6mg/mL = answer

13. You add 23mL of sterile water for injection to a 3g vial of antibiotic that has a powder volume of 3mL. What is the concentration, in mg/mL, of the reconstituted drug?

FV = 23mL + 3mL = 26mL 3g = 3000mg 3000mg/26mL = 115.4mg/mL 115.4mg/mL = answer

12. A 6g pharmacy bulk package of Fortaz is reconstituted with 26mL of sterile water for injection. What will be the final concentration of the drug if the powder volume of the Fortaz is 4mL?

FV = 26mL + 4mL = 30mL 6g = 6000mg 6000mg/30mL = 200mg/mL 200mg/mL = answer

8. If you add 27mL of diluent to a vial containing 2.5g of drug that has a powder volume of 3mL, what will be the concentration of the drug after reconstruction?

FV = 27mL + 3mL = 30mL 2.5g = 2500mg 2500mg/30mL = 83.3mg/mL 83.3mg/mL = answer

37. A 1.5g vial of Unasyn contains two drugs: 1g ampicillin and 0.5g of sulbactam. The powder volume of the Unasyn is 0.8mL. The label instructions indicate that 3.2mL of SWFI Up should be used to reconstitute the drug. What is the concentration of each of the drugs.

FV = 3.2ml + 0.8ml = 4 ml 1G = 1,000mg 0.5G = 500mg Ampicillin: 1000 mg/4 ml = 250 mg/ml Sulbactam: 500 mg/4 ml = 125 mg/ml

35. What is the concentration in g/mL of 35g of a drug with a powder volume of 4mL if 31mL of sterile water for injection are added to the vial?

FV = 31ml + 4ml = 35 ml 35G/35 ml = 1G/ml

27. Using another vial of the antibiotic used in question 26, if 36.8mL of sterile water for injection is added to the vial what is the concentration of the reconstituted solution?

FV = 36.8ml + 3.2ml = 40ml 10,000,000units/40 ml = 250,000units/ml

40. If 7.2mL of SWFI are added to 16g of powdered medication with a powder volume of 0.8mL, what is the final concentration in g/mL of the reconstituted solution?

FV = 7.2ml + 0.8ml = 8ml 16G/8ml = 2G/ml

6. If you add 8mL of sterile water for injection to a volume of 5MU penicillin that has a powder volume of 2mL, what is the concentration of the drug in solution? (Hint: 5MU is an abbreviation for 5 million units.).

FV = 8mL + 2mL = 10mL 5MU = 5,000,000units 5,000,000units/10mL = 500,000units/1mL 500,00units/1mL = answer

23. A 40g vial of an antibiotic has a powder volume of 5.2mL. If 94.8mL of sterile water for injection are added to the vial, what is the concentration (mg/mL) of the reconstituted solution?

FV = 94.8 ml + 5.2 ml = 100 ml 40G = 40,000mg (40,000 mg/100 ml) = 400 mg/ml

31. A vial contains two different drugs: Medication A, 3.5mg; and Medication B, 35mg. The two drugs together have a powder volume of 0.5mL. What is the concentration of each medication if 3mL of sterile water for injection is added to the vial?

Medication A, 3.5 mg, is 10% of Medication B, 35mg Total powder volume is 3.5 ml Medication A: 3.5 mg/3.5 ml = 1 mg/ml Medication B: 35 mg/3.5 ml = 10 mg/ml

41. A powdered drug is available in 50mg vials. The label states to add 3.8mL of water for injection to get a concentration of 12.5mg/mL. a) What is the powder volume of the drug? b) The physician orders 18.75mg. How many mL are needed for this dose?

a) (12.5mg/1mL) = (50mg/x) x = 4ml = FV PV= FV - DA PV = 4ml - 3.8ml PV = 0.2 ml b) (12.5mg/1mL) = 50mg/x) x = 1.5mL

29. A powdered drug is available in vials containing 35mg of the drug. The reconstitution instructions indicate to add 6.2mL or sterile water for injection to obtain a concentration of 5mg/mL. a) What is the powder volume of the drug? b) How many mL of the reconstituted drug are needed for a 2.5mg dose in 50mL NS?

a) (5mg/1mL) = (35mg/x) x = 7mL = FV PV = 7mL - 6.2mL PV = 0.8mL b) (5mg/1mL) = (2.5mg/x) x = 0.5mL

24. A patient is ordered a 130mg dose of a drug in 50mL of D5W. A vial contains 1g of the powdered drug. The drug has a powder volume of 0.4mL. a) How many mL of sterile water for injection are needed to obtain a concentration of 250mg/mL? b) How many mL will be needed to fill the patient order?

a) 1g = 1000mg (250mg/1mL) = (1000mg/x) x = 4mL = FV DA = 4mL - 0.4mL DA = 3.6mL b) (130mg/1000mg) = (x/4mL) x = 0.52mL

28. A 1g vial of nafcillin is reconstituted with 3.4mL of sterile water for injection. A concentration of 250mg/mL nafcillin is obtained. a) What is the powder volume of the nafcillin? b) If a patient requires a 200mg dose in 250mL of D5W, how many mL of the reconstituted solution are needed?

a) 1g = 1000mg (250mg/1mL) = (1000mg/x) x = 4mL = FV PV = 4mL - 3.4mL PV = 0.6mL b) (250mg/1mL) = (200mg/x) x = 0.8mL

21. A 2g vial of a drug has a powder volume of 1.5mL. a) How many mL of sterile water for injection will you add to obtain a concentration of 125mg/mL? b) A patient dose is 325mg. How many mL of the reconstituted solution will you use?

a) 2g = 2000mg x = 16mL = FV 16mL - 1.5mL = 14.5mL b) (125mg/1mL) = (325mg/x) x = 2.6mL = FV

33. A physician has ordered a loading dose of 600mg in 50mL of normal saline. The powder volume of the drug ordered is 0.9mL. a) How many mL of sterile water for injection must be added to the 5g vial of drug to obtain a concentration of 250mg/mL? b) How many mL of the reconstituted solution are needed for the patient's dose?

a) 5g = 5000mg (250mg/1mL) = (5000mg/x) x = 20mL = FV DA = 20mL - 0.9mL DA = 19.1mL b) (20mL/5000mg) = (x/600mg) x = 2.4mL

36. A patient requires 250mcg of a medication in 50mL of D5W. A 4mg vial of the medication has a powder volume of 0.1mL 3.9mL of sterile water for injection is added to the vial. a) What is the final concentration of the reconstituted solution? b) How many mL does the patient need?

a) FV = 3.9ml + 0.1ml = 4ml 4 mg/4 ml = 1 mg/ml b) 250 mcg = 0.25 mg Therefore 0.25 ml are needed (since the ratio is 1 mg/ml)

44. If 20 million units of penicillin have a powder volume of 8mL, what is the final concentration for the following quantities of sterile water for injection used for reconstitution? a) 32mL b) 42mL c) 72mL d) 92mL

a) FV = 32mL + 8mL = 40mL 20,000,000units/40mL = 500,000units b) FV = 42mL + 8mL = 50mL 20,000,000units/50mL = 400,000units c) FV = 72mL + 8mL = 80mL 20,000,000units/80mL = 250,000units d) FV = 92mL + 8mL = 100mL 20,000,000units/100mL = 200,000units