Assignment on Percentage, Ratio Strength, and Other Expressions of Concentration PDF

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Part A: Percentage Calculations 1. CLOBEX lotion contains 0.05% w/v clobetasol propionate in 118 mL containers. Calculate the content of drug in milligrams. (3 pts) Convert 0.05% to decimal

Calculate the content of drug 118 mL × 0.0005 = 0.059 g Convert 0.059 g to mg 59 mg

2. What is the percentage strength (v/v) if 225 g of a liquid having a specific gravity of 0.8 is added to enough water to make 1.5 liters of solution? (3 pts) 225 g of water measures 225 mL 225 mL / 0.8 = 281.25 mL of active ingredient Convert 1.5 L to mL

Calculate percentage strength 18.75% v/v

3.Each gram of LOTRISONE lotion contain 10 mg of clotrimazole and 0.643 mg of betamethasone dipropionate. Calculate the percentage concentration of each of these two agents in the lotion. (3 pts) Convert 10 mg to g

X = 1% clotrimazole Convert 0.643 mg to g

X = 0.0643% betamethasone dipropionate

4. Given the prescription below

Rx

Progesterone, micronized

4g

Glycerin

5 mL

Methylcellulose (1%) Solution

50 mL

Cherry Syrup ad

100 mL

(a) What is the percentage concentration (w/v) of progesterone in the prescription? (1 pt)

4% w/v of progesterone (b) What is the percentage concentration (w/v) of methylcellulose in the prescription? (1 pt)

50 mL x 0.01 = 0.5 g 0.5% w/v of methylcellulose (c) What is the percentage concentration (v/v and w/v) of glycerin (sp gr 1.25) in the prescription? (2 pts) 5% v/v and 6.25% w/v glycerin

5% v/v of glycerin

6.25% w/v of glycerin

Part B: Ratio Strength Calculations 5. Express each of the following as a percentage strength: (3 pts) (a) 1:1500

X = 0.067 % (b) 1:10,000

X = 0.01% (c) 1:250 0.4%

X = 0.4%

6. Express each of the following as a ratio strength: (3 pts) (a) 0.125%

Ratio Strength = 1:800 (b) 2.5% 1:40

Ratio Strength = 1:40 (c) 0.80%

Ratio Strength = 1:125

7. Express each of the following concentrations as a ratio strength: (2 pts) (a) 2 mg of active ingredient in 2 mL of solution

Ratio Strength = 1:1000 (b) 0.275 mg of active ingredient in 5 mL of solution 18,182 Ratio Strength = 1:18,182 8. An injection contains 0.5% (w/v) of lidocaine hydrochloride and 1:200,000 (w/v) epinephrine. Express the concentration of lidocaine hydrochloride as a ratio strength and that of epinephrine as a percentage. (3 pts) 0.5% (w/v) of Iodocaine hydrochloride as ration strength Ratio Strength = 1:200

1:200,000 (w/v) epinephrine as percentage Percentage Strength = 0.0005%

Part C: Parts per Million Calculations 9. Purified water contains not more than 10 ppm of total solids. Express this concentration as a percentage. (3 pts) 10 ppm = 10 parts in 1,000,000 1,000,000/10 = 100,000 Ratio Strength = 1:100,000

X = 0.001 % w/v

10. How many grams of sodium fluoride should be added to 100,000 liters of drinking water containing 0.6 ppm of sodium fluoride to provide a recommended concentration of 1.75 ppm? (3 pts) 1.75 ppm - 0.6 ppm = 1.15 ppm = 1.15 mg/L

115 g sodium fluoride...