Podcast
Questions and Answers
What does a percentage concentration of 10% w/v indicate?
What does a percentage concentration of 10% w/v indicate?
- 10 mL of drug in every 100 mL of solution
- 10 g of drug in every 10 mL of solution
- 10 g of drug in every 100 mL of solution (correct)
- 10 g of drug in every 100 g of solution
Which concentration expression is appropriate for a liquid ingredient mixed with a solid vehicle?
Which concentration expression is appropriate for a liquid ingredient mixed with a solid vehicle?
- % v/v
- % v/w
- % w/v
- % w/w (correct)
When converting percent strength to ratio strength, which of the following is true?
When converting percent strength to ratio strength, which of the following is true?
- A higher percent strength equals a lower ratio strength
- Percent strength of 5% is equivalent to a ratio strength of 1:20 (correct)
- The ratio strength is numerically equal to the percent strength
- Percent strength can only be converted to ratio strength for solid preparations
What does a concentration expressed as w/v typically represent?
What does a concentration expressed as w/v typically represent?
In a pharmaceutical preparation, the choice of calculation basis depends primarily on what factor?
In a pharmaceutical preparation, the choice of calculation basis depends primarily on what factor?
What is the correct interpretation of 10% w/w in a preparation?
What is the correct interpretation of 10% w/w in a preparation?
When a powdered substance is dissolved in a liquid vehicle, which concentration calculation is generally used?
When a powdered substance is dissolved in a liquid vehicle, which concentration calculation is generally used?
In the ratio strength expression, what does a ratio of 1:100 indicate?
In the ratio strength expression, what does a ratio of 1:100 indicate?
Which of the following best describes the fundamental concept of concentration?
Which of the following best describes the fundamental concept of concentration?
What does ratio strength express?
What does ratio strength express?
If 2 mg of a drug is present in a 1 mL solution, what is the ratio strength (w/v) of the solution?
If 2 mg of a drug is present in a 1 mL solution, what is the ratio strength (w/v) of the solution?
To prepare 240 g of a 5% (w/w) solution, how much phenol is needed?
To prepare 240 g of a 5% (w/w) solution, how much phenol is needed?
Convert 4% w/v to mg/mL.
Convert 4% w/v to mg/mL.
How many grams of dextrose are needed for 4000 mL of a 5% solution?
How many grams of dextrose are needed for 4000 mL of a 5% solution?
What does ppm mean in concentration terms?
What does ppm mean in concentration terms?
If a solution has a ratio strength of 1:10,000, what would its concentration be in mg/mL?
If a solution has a ratio strength of 1:10,000, what would its concentration be in mg/mL?
Expressing 0.02% as ratio strength results in which representation?
Expressing 0.02% as ratio strength results in which representation?
Which of the following is NOT a way to express concentration?
Which of the following is NOT a way to express concentration?
What is the expression for the strength of very dilute solutions typically called?
What is the expression for the strength of very dilute solutions typically called?
Flashcards
Ratio Strength
Ratio Strength
A way of expressing concentration that compares the amount of active drug to the total amount of product.
1:X Ratio Strength
1:X Ratio Strength
A type of ratio strength expressed as a fraction; 1 part of active drug to the total number of parts in the product.
Percentage Concentration
Percentage Concentration
A type of concentration expression that uses a percentage (%) to represent the amount of active drug in a solution.
Weight-in-Volume (w/v)
Weight-in-Volume (w/v)
Signup and view all the flashcards
Volume-in-Volume (v/v)
Volume-in-Volume (v/v)
Signup and view all the flashcards
Weight-in-Weight (w/w)
Weight-in-Weight (w/w)
Signup and view all the flashcards
Milligram per Milliliter (mg/mL)
Milligram per Milliliter (mg/mL)
Signup and view all the flashcards
Parts Per Million (ppm)
Parts Per Million (ppm)
Signup and view all the flashcards
Percentage to Ratio Strength Conversion
Percentage to Ratio Strength Conversion
Signup and view all the flashcards
Ratio Strength to Percentage Conversion
Ratio Strength to Percentage Conversion
Signup and view all the flashcards
Concentration
Concentration
Signup and view all the flashcards
Percentage (in Pharmacy)
Percentage (in Pharmacy)
Signup and view all the flashcards
Percent Weight-in-Weight (% w/w)
Percent Weight-in-Weight (% w/w)
Signup and view all the flashcards
Percent Weight-in-Volume (% w/v)
Percent Weight-in-Volume (% w/v)
Signup and view all the flashcards
Percent Volume-in-Volume (% v/v)
Percent Volume-in-Volume (% v/v)
Signup and view all the flashcards
W/V (Weight in Volume)
W/V (Weight in Volume)
Signup and view all the flashcards
V/W (Volume in Weight)
V/W (Volume in Weight)
Signup and view all the flashcards
V/V (Volume in Volume)
V/V (Volume in Volume)
Signup and view all the flashcards
W/W (Weight in Weight)
W/W (Weight in Weight)
Signup and view all the flashcards
Study Notes
Concentration Expressions
- Concentration is the ratio of the amount of an ingredient to the amount of the product.
- Concentration can be expressed in various ways depending on the ingredients and product.
Objectives
- Define percent weight-in-volume, percent volume-in-volume, and percent weight-in-weight.
- Define ratio strength.
- Convert percent strength to ratio strength and vice versa.
- Calculate percentage strength and ratio strength of a pharmaceutical preparation.
- Use percent strength and ratio strength to calculate the amount of an ingredient present in a pharmaceutical preparation.
- Use percent and ratio strength to calculate the amount of an ingredient needed in compounding.
Concentration Basis
- Solid in liquid (w/v): weight of solid in volume of liquid.
- Liquid in solid (v/w): volume of liquid in weight of solid.
- Liquid in liquid (v/v): volume of liquid in volume of liquid.
- Solid in solid (w/w): weight of solid in weight of solid.
Percentage
- Percentage describes the number of parts of active drug relative to 100 parts of the total.
- Percentage must be accompanied by a description (e.g., w/w, w/v, v/v).
- % w/w: grams of active drug per 100 grams of product.
- % w/v: grams of active drug per 100 mL of product.
- % v/v: milliliters of active drug per 100 mL of product.
- Examples:
- 10% w/v = 10 g of drug in every 100 mL of total.
- 10% w/w = 10 g of drug in every 100 g of total.
Special Considerations in Percentage Calculations
- The nature of the ingredients determines the calculation basis.
- Powders dissolved in liquids (w/v).
- Powders mixed with solids/semisolids (w/w).
- Liquids in liquids (v/v).
- Weight may need to convert to volume or vice versa (using specific gravity).
- g = mL × specific gravity
- mL = g / specific gravity
Ratio Strength
- Ratio strength expresses concentration as parts of active drug relative to any number of parts of the whole.
- Ratio strength is expressed as 1 part active drug : total parts.
- Example: 1:1000 w/v means 1 part active drug in 1000 parts of total.
Percentage and Ratio Strength Interconversion
- Example: Convert 0.02% to ratio strength (1:5000).
- Example: Convert 1:4000 to percentage strength (0.025%).
Other Concentration Expressions
- Milligram per milliliter (mg/mL).
- Parts per million (ppm).
- Converting percentages to mg/mL and ppm.
Example Calculations
- Specific examples (weight-in-volume, volume-in-volume, weight-in-weight) are provided demonstrating calculations for various concentrations.
Studying That Suits You
Use AI to generate personalized quizzes and flashcards to suit your learning preferences.
