Practice Problems

Each gram of a lotion contains 10 mg of clotrimazole and 0.643 mg of betamethasone dipropionate. Calculate the percent concentration of each of these two agents in the lotion

1% w/w clotrimazole 0.0643% w/w betamethasone dipropionate

A specific gravity bottle weighs 23.66 g. when filled with water, it weighs 72.95 g; when filled with another liquid, it weighs 73.56 g. what is the specific gravity of the liquid?

1.012

10 mL of sulfuric acid weighs 18 g, what is its density?

1.8 g/mL

How many grams of a drug substance should be added to 240 ml of water to make 4% (w/w) solution?

10 g

A low-strength aspirin tablet contains 81 mg of aspirin per tablet. How many tablets may be prepared from 1 kg of aspirin?

12345 tablets

How many grams of sodium chloride should be used in preparing 500 ml of a stock solution such that is also the amount of 50 ml diluted to 1000 ml will yield a "1/3 normal saline" (0.3% w/v) for irrigation?

30 g

A pharmacist filled the following prescription: Ofloxacin Ophthalmic Solution 0.3% Disp. 10 mL Sig: 2 drops in eyes q 4 hours x 2 days; then 2 drops q 6 hours x 4 days How many mg of ofloxacin are contained in the dispensed prescription?

30 mg

The biotechnology drug filgrastim is available in syringes containing 480 micrograms of filgrastim per 0.8 mL. How many micrograms of the drug would be administered by each 0.5 mL injection?

300 mcg

An elixir contains 40 mg of drug in each 5 mL. How many milligrams of the drug would be used in preparing 4000 mL of the elixir?

32,000 mg

What is the volume, in milliliters, of 492g of nitric acid with a specific gravity of 1.40?

351 mL

A Pharmacist has a 5% stock solution of potassium permanganate from which 1L of a 1:5000 solution to dispense as a foot soak. How many milliliters of the stock solution are needed?

4 mL

How many milliliters of water should be added to a 300 ml of a 1:750 w/v of benzalkolium chloride to make a 1:2500 w/v solution?

700 mL

How many milliliters of water should be added to a pint of a 5% w/v solution to make 2% w/v solution?

709.5 mL

An inhalation aersol contains 225 mg of metaproterenol sulfate, which is sufficient for 300 inhalations. How many micrograms of metaproterenol sulfate would be contained in each inhalation?

750 mcg

If a syrup containing 65% w/v of sucrose is evaporated to 85% of its volume, what percentage (w/v) of sucrose will contain?

76%

A prescription drug cost the pharmacist $42.00 for a bottle of 100 tablets. What would be the cost for 24 tablets?

$10.08

A lotion contains 0.05% w/v clobetasol propionate in 118 mL containers. Calculate the content of drug, in mg.

59 mg

If 50 ml of a 1:20 w/v solution are diluted to 1000 ml, what is the ratio strength (w/v)

.25% or 1:400

If 15 ml of a 0.06% ATROVENT (ipratropium bromide) nasal spray were diluted with 6 ml of normal saline solution, what would be the final drug concentration?

0.043%

If 100 mL of a pharmaceutical preparation contains 20 microL of a 50% w/v solution of benzalkonium chloride, what is the percentage strength of that agent in the solution?

0.01%

The biotechnology drug interferon gamma-1b contains 100 mcg/0.5 mL. Calculate the percentage strength of the solution

0.02%

How many grams of potassium permanganate should be used in compounding the following prescription? Rx Potassium Permanganate 0.02% Purified Water ad 250 ml Sig. As directed

0.05 g

How many grams of potassium permanganate should be used in preparing 500 mL of a 1:2500 solutions?

0.2 g

A cyclosporine ophthalmic emulsion (RESTASIS) contains 0.05% w/v cyclosporine in 0.4 ml vial. Calculate the content of cyclosporine, in milligrams, per vial.

0.2 mg

How many grams of a 1:10 trituration are required to obtain 25 mg of drug?

0.25 g

An injection contains 5 mg of drug in each 10ml vial, if the dose of the drug for a patient is determined to be 150µg. How many milliliters should be administered.

0.3 mL

A vial contains 80 mg of drug in 2 mL of injection. How many milliliters of the injection should be administered to obtain 0.02 g of drug?

0.5 mL

In acute hypersensitivity reactions, 0.5 mL of 1:1000 (w/v) solution of epinephrine may be administered subcutaneously or intramuscularly. Calculate the mg of epinephrine given

0.5 mg

A 60-g tube of DESONATE gel contains 0.05% w/w desonide. Calculate the concentration of desonide on a mg/g basis.

0.5 mg/g

If 30 g of a 1% hydrocortisone were diluted with 12 g of Vaseline, what would be the concentration of hydrocortisone in the mixture?

0.71%

A 50 ml pycnometer if found to weigh 120 g when empty, 171 g when filled with water, and 160 g when filled with an un known liquid. Calculate the specific Gravity of the unknown weight?

0.78

If 250 mL of alcohol weighs 203 g, what is the density?

0.812 g/mL

A pycnometer weighs 21.62 g. Filled with water, it weighs 46.71 g; filled with another liquid, its weighs 43.28 g. Calculate the specific gravity of the liquid

0.86

A liquid contains 0.25 mg of a substance per mL. How many grams of the substance will 3.5 L contain?

0.875 g

If 27.8 mL of oil weighs 26.2 g, what is the specific gravity of the oil?

0.942

How many milligrams of hydrocortisone should be used in compounding the following prescription? Benzocaine 2% Hydrophilic Ointment ad 2g Make 24 such suppositories Sig: insert one as directed

0.96 g

If 54.96 mL of an oil weighs 52.78, what is the specific gravity of the oil?

0.9603

Convert 1:10,000 (w/v) to mg/mL

1 mg/ 10 mL

Calculate the percentage strength of an injection that contains 2 mg of hydromorphone hydrochloride in each mL of injection

1%

A pycnometer when filled with water weighs 23.56 g. When filled with an oil, weighs 24.72 g. Calculate the specific gravity of the liquid if the weight of the empty pycnometer is 12.06 g

1.10

If 150 mL of sorbitol solution weighs 170 g, what is its specific gravity?

1.133

The recommended dose for a brand of nicotine patch is one 21 mg dose per day for 6 weeks, followed by 14 mg per day for 2 weeks, and then 7 mg per day for 2 more weeks. What total quantity, in grams, would a patient receive during this course of treatment?

1.176 g

How many milliliters of a 10% stock solution needed to prepare 120 ml of a 0.1% Solution?

1.2 mL

If 2 fl. oz of glycerol weighs 74.1 g, what is its specific gravity?

1.25

If a pint of a certain liquid weighs 601 g, what is the specific gravity of the liquid?

1.27

If a liter of a cough syrup weighs 1285 g, what is its specific gravity?

1.285

In preparing 250ml of certain lotion, a Pharmacist used 4 ml of liquefied phenol. What was the percentage (v/v) of liquefied phenol in the lotion?

1.6%

A patient is instructed to take one 50 microgram tablet of pergolide mesylate a day for the first two days of treatment; 150 microgram/day on the third, fourth, and fifth days of treatment; 250 microgram/day on the sixth, seventh, and eighth days, and 350 microgram on the ninth day and return to the physician for assessment. During this treatment period, how many milligrams of drug were taken?

1.65 mcg

A formula for 1250 tablets contains 6.25 grams of diazepam. How many grams of diazepam should be used in preparing 350 tablets?

1.75 g

If 10 mL of sulfuric acid weighs 18 g and 10 mL of water (under the same conditions) weighs 10 g, the specific gravity of the acid is....

1.8

What is the percentage of zinc oxide in an ointment prepared by mixing 200 g of 10% ointment, 50 g of 20% ointment, and 100 g of 5% ointment? What is the percentage of zinc oxide in an ointment prepared by mixing 200 g of 10% ointment, 50 g of 20% ointment, and 100 g of 5% ointment?

10%

How many 0.1 mg tablets will contain the same amount of drug as 50 tablets, each of which contains 0.025 mg of the identical drug?

12.5 tablets

What is the LWQ of a substance with a SR of 6 mg and an acceptable error of 5%?

120 mg

How many milliliters of a 1:5000 w/v solution of the preservative lauralkonium chloride can be made from 125 ml of a 0.2% solution

1250 mL

A hemorrhoidal ointment contains, on w/w basis, 46.6% mineral oil, 1% pramoxine HCl, and 12.5% zinc oxide in an ointment base. Calculate the grams of each ingredient, including the ointment base, in each 30 g tube

13.98 g mineral oil 0.3 g pramoxine HCl 3.75 g zinc oxide 11.97 g ointment base

How many grams of phenol should be used to prepare 240 g of a 5% (w/w) solution in water?

15 g

An oral suspension contains 1.5g of medications in a pint. Calculate the quantity of medication , in milligrams, present in each 5ml dose?

15.9 mg

A penicillin V potassium preparation provides 400,000 units of activity in each 250 mg tablet. How many total units of activity would a patient receive from taking four tablets a day for 10 days?

16,000,000 units

What is the percentage strength if 225 g of a liquid having a specific gravity of 0.8 is adde to enough water to make 1.5 L of the solution?

18.75%

A patient is 6 ft 1 inch tall. How tall is the patient in cm? In m?

185.4 cm 1.854 m

What is the ratio strength (w/v) of a solution made by dissolving five tablets, each containing 2.25 g of sodium chloride, in enough water to make 1800 ml

1:160

A certain injectable contains 2 mg of a drug per milliliter of solution. What is the ratio strength (w/v) of the solution?

1:500

The blood serum concentration of of the antibacterial drug ciprofloxacin increases proportionally with the dose of drug administered. If a 250 mg dose of the drug results in a serum concentration of 1.2 micrograms of drug per mL of serum, how many micrograms of drug would be expected per mL of serum following a dose of 500 mg of drug?

2.4 micrograms

An injection contains 3 mg of medication in each mL. If a physician prescribes a dose of 0.5 mg to be administered to a hospital patient three times daily, how many mL of injection will be required over a 5 day period?

2.5 mL

How should you prepare 100 ml of a 2% (w/w) solution of a drug substance in a solvent having a specific gravity of 1.25?

2.55 g

How many L of a mouthwash can be prepared from 100 mL of cinnamon flavor if its concentration is to be 0.5%?

20 L

How many milliliters of a 1% stock solution of a certified red dye should be used in preparing 4000 ml of a mouthwash that is to contain 1:20,000 w/v of the certified red dye as a coloring agent?

20 mL

A medication order calls for 1000 milliliters of a dextrose intravenous infusion to be administered over an 8 hours period. Using an intravenous administration set that delivers 10 drops/milliliters, how many drops per minute should be delivered to the patient?

20.8 or 21 drops/min

How many grams of dextrose are required to prepare 4000 mL of a 5% solution?

200 g

How many milliliters of water should be added to 375 ml solution containing 0.5 g of benzalkolium chloride to make 1:5000 solution

2125 mL

How many milliliters of 95% v/v alcohol and how much water should be used in compounding the following prescription Rx Xcaine 1 g Alcohol 70% 30 ml Sig. Ear drops

22.1 mL of 95% alcohol Enough water to make 30 mL

How many milliliters of 37% w/w HCL having a SG of 1.2 are required to make 1000 ml of diluted HCL 10% w/v?

225 mL

The dose of a drug is 0.5 mg/kg of body weight/day. What is the equivalent dose in µg/Ib/day?

227.3 microg/lb/day

A cough syrup contains 10 mg of dextromethorphan hydrobromide per 5 mL. How many milligrams of the drug are contained in a 120 mL container of the syrup?

240 mg

If 100 capsules contain 500 mg of an active ingredient, how many milligrams of the ingredient will 48 capsules contain?

240 mg

A patient is determined to have a total cholesterol level of 240mg/dl. What is the equivalent in mg/100ml?

240 mg / 100 mL

How many milligrams of hexachlorophene should be used in compounding the following prescription? Rx Hexachlorophene 1:400 Hydrophilic Ointment ad. 10 g Sig. Apply

25 mg

What is the percentage of v/v of a solution of 800 g of a liquid with specific gravity of 0.8 in enough water to make 4000ml

25%

How many grams of a drug substance are required to make 120 ml of a 20% (w/w) solution having a specific gravity of 1.15?

27.6 g

What is the percentage strength of alcohol in a mixture of 500 ml of a solution containing 40% v/v alcohol, 400 ml of a second solution containing 21% v/v alcohol, and sufficient quantity "qs" of a nonalcoholic third solution to make a total of 1000 ml?

28.4%

How many grams of 20% benzocaine ointment and how many grams of ointment base (diluent) should be used in preparing 5Ib of 2.5% benzocaine ointment?

284 g benzocaine 1986 g diluent

DIPROLENE lotion contains 0.05% w/w betamethasone dipropionate. If the specific gravity of the lotion is 0.96, how many milligrams of betamethasone dipropionate would be present in 1 60-ml container of the lotion?

29 mg

What is the weight, in grams, of 3620 mL of alcohol with a specific gravity of 0.82?

2968 g

What is the volume, in pints, of 50 lbs of glycerin having a specific gravity of 1.25?

38.4 pints

What is the volume, in milliliters, if 1 Ib of methyl salicylate with a specific gravity of 1.185?

383.1mL

If 3 tablets contain 975 milligrams of aspirin, how many milligrams should be contained in 12 tablets?

3900 mg

Convert a product of 1 g per 250 mL to mg/mL

4 mg/mL

The solvent for the extraction of a vegetable drug is 70% alcohol. In what proportions may 95%, 60% and 50% alcohol be mixed to prepare a solvent of the desired concentration?

4 parts 50% 2 parts 60% 5 parts 95%

In what proportion should alcohols of 95% and 50% be mixed to make 70%

4 parts 95% 5 parts 50%

The starting dose of sodium oxybate oral solution is 4.5 g/night divided into two equal doses and administered 2.5 to 4 hours apart. How many milliliters of the oral solution containing sodium oxybate, 500 mg/mL, should be administered in each divided dose?

4.5 mL

The topical antibacterial solution (HIBICLENS) contains 4% w/v chlorhexidine gluconate in 4-fluidounce containers. Calculate the content of chlorhexidine gluconate, in grams?

4.73 g

If 5 g of boric acid are added to 100 ml of water; what is the percentage strength (w/w) of the solution?

4.76%

What weight of a 5% (w/w) solution can be prepared from 2 g of active ingredient?

40 g

Convert 4% (w/v) to mg/mL

40 mg/mL

What is the volume, in mL, of 1 lb of benzyl benzoate having a specific gravity of 1.12?

405.36

An elixir of ferrous sulfate contains 220 mg of ferrous sulfate in each 5 mL. If each milligram of ferrous sulfate contains the equivalent of 0.2 mg of elemental iron, how many milligrams of elemental iron would be represented in each 5 mL of the elixir?

44 mg

If 30 mL represents 1/6 of the volume of a prescription, how many mL will represent 1/4 of the volume?

45 mL

How much drug should be used in preparing 50 ml of a solution such that 5 ml diluted to 500 ml will yield a 1:1000 solution

5 g

If 1500 g of a solution contains 75 g of a drug substance, what is the percentage strength (w/w) of the solution?

5%

If 500 ml of a 15% v/v solutions are diluted to 1500 ml, what will be the percentage strength (v/v)?

5%

A prefilled syringe contains 20 mg of drug in 2 mL of solution. How many micrograms of drug would be administered by an injection of 0.5 mL of the solution?

5,000 mcg

Adalimumab, a recombinant human monoclonal antibody, is available in a prefilled syringe containing 40 mg/0.8 mL of injection. Calculate the concentration of drug on a mg/mL.

50 mg/mL

How many colchicine tablets, each containing 600 mcg, may be prepared from 30 g of colchicine?

50,000 tablets

How many milligrams of a 1:10 dilution of colchicine should be used by a manufacturing pharmacist in preparing 100 capsules for clinical drug study if each capsule is to contain 0.5 mg of colchicine?

500 mg

How many grams of 10% w/v ammonia solution can be made from 1800 g 28% w/w strong ammonia solution?

5040 g

What is the volume, in mL, of 1 kg of sulfuric acid with a specific gravity of 1.83?

546.45 mL

How many milliliters of liquefied phenol should be used in compounding the following prescription Rx Liquefied phenol 2.5% Calamine Lotion ad 240 ml Sig. For external use

6.0 mL

How many milliliters of 85% w/w phosphoric acid having a SG of 1.71 should be used in preparing 1 gallon of ¼ % w/v phosphoric acid solution to be used for bladder irrigation?

6.5 mL

If 1000ml of syrup with a specific gravity of 1.313 contains 850g of sucrose, what it is percentage strength (w/w)?

64.7%

What is the weight, in grams, of 2 fl. oz, of a liquid having a SG of 1.118?

66.12 g

What is the weight, in pounds, of 5 pints of nitric acid?

7.4 lbs

Peppermint spirit contains 10% v/v of peppermint oil. What volume of spirit will contain 75 ml of peppermint?

750 mL

A piece of copper metal weighs 53.6 g, and has a volume of 6 mL. Calculate the density

8.93 g/mL

How many milliliters of a 1:400 w/v stock solution should be used to make 4 liters of a 1:2000 w/v solution?

800 mL

How much water should be mixed with 5000 ml of 85% v/v alcohol to make 50% v/v alcohol?

8500 mL

What is the weight, in kg, of 5 liters of sulfuric acid with a specific gravity of 1.84?

9.2 kg

What is the weight in grams of 1200 mL of acetone, which has a specific gravity of 0.79?

948 g

A torsion prescription balance has a sensitivity requirement of 6.5 mg. Explain how you would weigh 15 mg of atropine sulfate with an accuracy of +/- 5% using lactose as the diluent?

Arbitrary number of 10 Weigh 150 mg of atropine Dilute with 1150 mg of lactose to make 1300 mg Weigh 1/10 of dilution to yield 15 mg

A torsion prescription balance has a sensitivity requirement of 0.004 grams. Explain how you would weight 0.008 grams of a substance with an error not greater than 5%.

Arbitrary number of 10 Weigh 0.08 g of substance Weight 0.72 g of diluent to make 0.8 g total Take 1/10 of 0.8 (0.08 g)

A prescription balance has a sensitivity requirement of 0.006 grams. Explain how you would weigh 0.012 grams of a drug with an error not greater than 5%, using lactose as the diluent.

Arbitrary number of 10 Weight 0.12 g of drug Weigh 1.08 g of diluent to make 1.2 g total Measure 1/10 of 1.2 ( 0.12 g)

A prescription balance has a SR of 6.5 mg. Explain how you would weight 20 mg of a substance with an error no greater than 2%

Arbitrary number of 20 Measure 400 mg of substance 6100 mg of diluent to make 6500 mg total Take 1/20 of total

A formula calls for 0.5 milliliter of hydrochloric acid, using a 10-milliliters graduated cylinder calibrated from 2-10 milliliter divisions, explain how you would obtain the desired quantity of hydrochloric acid by aliquot method?

Arbitrary number of 4 Measure 2 mL of hydrochloric acid Measure 6 mL of water to make 8 mL of solution Measure 1/4 of solution to yield .5 mL of hydrochloric acid

A prescription calls for 0.2 ml of clove oil, Using 5 ml graduate calibrated in units of 0.5ml, how would you obtain the required amount of the clove oil using the aliquot method and alcohol the diluent?

Arbitrary number of 5 Measure 1 mL of clove oil Measure 2.5 mL of alcohol to make 1.5 mL of total solution Measure 1.5 of solution to yield 0.2 mL of clove oil

A prescription calls for 50 mg of chlorpheniramine maleate. Using a prescription balance with a sensitivity requirement of 6 mg, explain how you would obtain the required amount of chlorphenitamine maleate with an error not greater than 5%

Arbitrary number of 50 Weigh 500 mg of chlorpheniramine Weigh 700 mg of diluent to make 1200 mg of total solution Measure 1/10 of 1200 (120 mg)

Prescription: 4 g Progesterone 5 mL glycerin 50 mL (1%) Methylcellulose solution 100 mL cherry syrup ad a. what is the percentage concentration (w/v) of progesterone? b. What is the percentage concentration (w/v) of methylcellulose? c. What is the percentage concentration (v/v and w/v ) of glycerin (SG 1.25)?

a. 4% b. 0.5% c. 5% v/v 6.25% w/v