Slide 1 Pharmaceutical Measurements and Calculations

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Slide 2 ### Presentation Topics

Systems of Pharmaceutical Measurement

Basic Calculations Used in Pharmacy Practice

Advanced Calculations Used in Pharmacy Practice

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Slide 3 ### Learning Objectives

Describe four systems of measurement commonly used in pharmacy and convert units from one system to another.

Explain the meanings of the prefixes most commonly used in metric measurement.

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Slide 4 ### Learning Objectives

Convert from one metric unit to another (e.g., grams to milligrams).

Convert Roman numerals to Arabic numerals.

Convert time to 24 hour military time.

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Slide 5 ### Learning Objectives

Convert temperatures to and from the Fahrenheit and Celsius scales.

Round decimals up and down.

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Slide 6 ### Learning Objectives

Perform basic operations with proportions, including identifying equivalent ratios and finding an unknown quantity in a proportion.

Convert percentages to and from fractions, ratios, and decimals.

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Slide 7 ### Learning Objectives

Perform fundamental dosage calculations and conversions.

Solve problems involving powder solutions and dilutions.

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Slide 8 ### Learning Objectives

Use the alligation method to prepare solutions.

Calculate the specific gravity of a liquid.

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Slide 9 ### Systems of Pharmaceutical Measurement

The metric system

Common measures

Numeric systems

Time

Temperature

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Slide 10 ### The Metric System

Pharmacists and pharmacy techs must make precise measurements daily

Most important measurements are

Temperature

Distance

Volume

Weight

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Slide 11 ### Terms to Remember

metric system

a measurement system based on subdivisions and multiples of 10; made up of three basic units: meter, gram, and liter

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Slide 12 ### Terms to Remember

meter

the metric system’s base unit for measuring length

gram

the metric system’s base unit for measuring weight

liter

the metric system’s base unit for measuring volume

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Slide 13 ### The Metric System

Legal standard of measure for pharmaceutical measurements

Developed in France in the 1700s

Has several advantages

Based on decimal notation

Clear correlations among units of measurement

Used worldwide

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Slide 14 ### The Metric System

Uses standardized units of Systeme International (SI)

Three basic units

Meter (distance, little use in pharmacy)

Gram (weight, used for solid form meds)

Liter (volume, used for liquid meds)

Numbers expressed as decimals rather than fractions

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Slide 15 ### The Metric System

An error of a single decimal place is an error of a factor of 10.

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Slide 16 Slide 17 Slide 18 ### Common Measures

Common measures are approximate.

Three types of common measures are used in the pharmacy:

Apothecary

Avoirdupois

Household

Common measures are often converted to metric equivalents.

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Slide 19 ### Common Measures

© Paradigm Publishing, Inc.

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Slide 20 ### Common Measures

For safety reasons, the use of the apothecary system is discouraged. Use the metric system.

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Slide 21 Slide 22 Slide 23 ### Common Measures

Always carefully check and double-check all calculations.

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