Pharmaceutical Formulas: Reduction and Enlargement

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Questions and Answers

What is the first step in reducing or enlarging a formula using the ratio and proportion method?

Calculate the conversion factor.

List all the ingredients.

Cross-multiply the ingredients.

Identify the desired total quantity. (correct)

Which formula represents the relationship needed to find the amount of each ingredient when enlarging a formula?

$rac{Total\,quantity\,of\,official\,formula}{X} = rac{Amount\,of\,each\,ingredient}{Total\,quantity\,desired}$

$rac{Amount\,of\,each\,ingredient}{Total\,quantity\,desired} = rac{Total\,quantity\,of\,official\,formula}{X}$

$rac{Amount\,of\,each\,ingredient\,in\,the\,official\,formula}{Total\,quantity\,of\,official\,formula} = rac{X}{Total\,quantity\,desired}$ (correct)

$rac{Total\,quantity\,desired}{Total\,quantity\,of\,official\,formula} = rac{X}{Amount\,of\,each\,ingredient}$

What value for peppermint oil would be calculated to make 240 ml of Peppermint Spirit from the official formula?

12 ml

240 ml

24 ml (correct)

30 ml

If the total quantity desired of a preparation is 600 ml and the total quantity of the official formula is 200 ml, what would be the conversion factor?

3 Signup and view all the answers

What is the correct calculation to find the amount of peppermint powder needed for 240 ml of the preparation?

$1000X = 2400$ Signup and view all the answers

What must be ensured when using the conversion factor method?

The units must be compatible and the same. Signup and view all the answers

When using the ratio and proportion method, what is the next step after cross-multiplying?

Isolate the variable X. Signup and view all the answers

How is the conversion factor calculated?

By dividing the total quantity desired by the total quantity of official formula. Signup and view all the answers

In the method of reducing a formula, if the official formula calls for 80 ml and the desired amount is 40 ml, what is the ratio for peppermint oil?

$rac{1}{2}$ Signup and view all the answers

What is the main objective of performing calculations to reduce or enlarge formulas?

To provide accurate dosages as per needs. Signup and view all the answers

What must be confirmed when using the ratio and proportion method to scale a formula?

The total quantity desired and the total quantity of the official formula are in the same units. Signup and view all the answers

When using the conversion factor method, what is essentially the key step?

Finding the conversion factor by dividing total quantities. Signup and view all the answers

What is a common mistake when calculating ingredient amounts in formula enlargement?

Using different units without conversion. Signup and view all the answers

How is the amount for a specific ingredient determined when applying the ratio and proportion method?

By multiplying the ratio by the total desired quantity. Signup and view all the answers

What precedes the calculation of each ingredient's amount when enlarging a formula?

Identifying the conversion factor between the official and desired quantities. Signup and view all the answers

When using the conversion factor method, what does the factor represent?

The ratio of ingredients to the desired total volume. Signup and view all the answers

When calculating amounts for a preparation, how are proportions in an official formula typically listed?

In grams or liters depending on the ingredient type. Signup and view all the answers

In the example given for calculating Peppermint Spirit, what was the primary operation used to solve for X?

Cross multiplication. Signup and view all the answers

Study Notes

Reducing and Enlarging Formulas

Pharmaceutical preparations often use pre-existing formulas
These formulas are often listed in USP/NF (United States Pharmacopeia/National Formulary)
Formulas specify the amount of each ingredient needed to make a particular amount of preparation
It's necessary to reduce or enlarge formulas to meet various needs

Objectives

Calculate to reduce or enlarge pharmaceutical formulas using metric units
Calculate to reduce or enlarge pharmaceutical formulas using proportional parts

Introduction

Most pharmacy preparations are based on proven formulas
These formulas already tested and approved
Formulas list the amount of each ingredient needed to produce a specific quantity of preparation
Sometimes there's a need to modify formula quantities to suit specific requirements

Ratio and Proportion Method

A method to calculate adjusted ingredient amounts
The ratio of the desired quantity to the original quantity is equal to the ratio of the needed ingredient amount to the original ingredient amount.
Example calculation to make 240 ml of Peppermint Spirit, given a base formula for 1000ml
- Calculation involves cross-multiplication to solve for the required amount of each ingredient.
- Peppermint oil: 24 ml
- Peppermint powder: 2.4 g

Conversion Factor Method

An alternate method for formula adjustments
Calculate a conversion factor (desired quantity / original quantity)
Multiply the conversion factor by the amount of each ingredient in the original formula to determine the required amount
Ensure that the units in the 'desired' and 'original' quantities are the same.

Example: Cocoa Syrup

Using a conversion factor of 0.12 (120 ml / 1000 ml)
Determine needed ingredient quantities for a 120 ml batch
- Exact ingredient amounts calculated using the formula
- Examples of ingredients calculated for a 120ml batch: 21.6 g cocoa, 72.0 g sucrose, 21.6 g liquid glucose, 6 ml glycerin, 0.24 g NaCl, 0.024 of vanillin, etc (and 120ml water)

Formulas with Proportional Parts

Formulas using "parts" instead of specific weights or volumes
"Parts" represent relative proportions of each ingredient
Solid ingredients often measured in grams; liquids, in milliliters
Example provided, calculating the adjusted amounts for a 1000g ointment batch from a formula that states:
- Coal Tar: 5 parts
- Zinc Oxide: 10 parts
- Hydrophilic Ointment: 50 parts
- Total Parts = 65, and this combination will make a total of 1000g.
- Adjusted amounts calculated resulting in: 76.92g Coal Tar, 153.85g Zinc Oxide, and 769.23g Hydrophilic Ointment.

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Description

This quiz focuses on the essential calculations needed to reduce or enlarge pharmaceutical preparation formulas. It covers the use of metric units and the ratio and proportion method for adjusting ingredient amounts accurately. Perfect for pharmacy students and professionals looking to enhance their knowledge of formula adjustments.