22 Questions
What is the total volume of the final product in the first procedure?
250 ml
What is the weight of Calamine in the first procedure?
37.5 gm
What is the volume of water added to the beaker in the second procedure?
44.5 ml
What is the purpose of adding liquefied phenol in the first procedure?
To provide a preservative effect
What is the volume of the final product in the second procedure?
60 ml
What is the purpose of adding glycerin in the first procedure?
To add moisture to the product
What is the ratio of grams of active ingredient in 100 grams of solution according to weight/weight percentage?
1:100
How many milliliters of distilled water are required to complete the volume to 50ml in the first procedure?
13.5 ml
What is the equivalent expression of 30%?
All of the above
What is the volume of the active ingredient in 100ml of solution according to volume/volume percentage?
100 ml of active ingredient
How many grams of glycerin are required to prepare 250g of 5% w/w solution?
12.5g
What is the purpose of the formula Quantity of formula desired / Quantity of formula given = F?
To reduce or enlarge the formula
What is the unit of measurement for bentonite in the given prescription?
Grams
What is the purpose of adding amaranth solution to the mixture in the first procedure?
To add color to the solution
What is the primary characteristic of a solution in pharmaceutical preparations?
Single phase system with one or more soluble chemical substances
What is the first step in the general procedure of preparing a simple solution?
Weigh the solid ingredient
What percentage of the final volume of the prescription is used to subtract the volume of the liquid ingredient?
Three-quarters (3/4)
What is the purpose of transferring the content of the beaker to a measuring cylinder?
To complete the volume with the vehicle
What is the label color for external use?
Purple or red
In Example 1, how much water is used to dissolve NaCl initially?
150 ml
In Example 2, how much water remains after subtracting the volume of the coloring agent?
65 ml
What is the final step in the procedure of preparing a simple solution?
Transfer to a suitable container and label it
Study Notes
Pharmaceutical Calculations
- Percent means by hundred or in a hundred, can be expressed as a ratio, common or decimal fraction.
- There are three types of percentage: Weight/Weight, Weight/Volume, and Volume/Volume.
Preparation of Simple Solutions
- General procedure:
- Weigh the solid ingredient and put it in a beaker.
- Subtract the volume of liquid ingredient from ¾ of the final volume of the prescription.
- Dissolve the solid ingredients in the remaining amount of the vehicle.
- Add the liquid ingredient.
- Convert the content of the beaker into the measuring cylinder and complete the volume up to the required amount by the addition of the vehicle.
- Transfer the content of the measuring cylinder to a wide mouth bottle and put the suitable label.
Examples of Simple Solutions
-
Example 1: NaCl 25mg, Water q.s. 200ml
- Calculate 200ml x 3/4 = 150ml of water used to dissolve NaCl initially.
- Procedure: Weigh 25mg of NaCl, dissolve in 150ml of water, and complete the volume with water to 200ml.
-
Example 2: NaCl 50mg, Coloring agent 10ml, Water q.s. 100ml
- Calculate 100ml x 3/4 = 75ml, then subtract 10ml of coloring agent to get 65ml of water used to dissolve NaCl initially.
- Procedure: Weigh 50mg of NaCl, dissolve in 65ml of water, add 10ml of coloring agent, and complete the volume with water to 100ml.
Reducing and Enlarging Formulas
- Formula: Quantity of formula desired / Quantity of formula given = F
- Multiply each ingredient by factor F to get the required quantity.
Procedure for Calamine Lotion
- Weigh each solid ingredient alone and put in a beaker.
- Measure 174ml of water and dissolve solid substances with stirring.
- Add 1.25ml of liquefied phenol and 12.5ml of glycerin to the beaker with stirring.
- Transfer to the graduated cylinder and complete the volume with water to 250ml.
- Transfer to the suitable container and label it.
Procedure for Sodium Bicarbonate Solution
- Weigh 1gm of sodium bicarbonate and put in a beaker.
- Measure 44.5ml of water and dissolve sodium bicarbonate with stirring.
- Add 0.5ml of Tr. Of cardamom to the beaker with stirring.
- Transfer to the graduated cylinder and complete the volume with water to 60ml.
- Transfer to the reagent bottle and put label.
A step-by-step guide to preparing a NaCl solution, including measuring and mixing the ingredients. Also covers the concept of percentage and its representation as a ratio or decimal fraction.
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