1. Pharmaceutical Measurements and Calculations
Pharmacy Practice, Fourth Edition
Pharmaceutical Measurements and Calculations 1
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2. Presentation Topics Systems of Pharmaceutical Measurement
Pharmacy Practice, Fourth Edition
Presentation Topics
Systems of Pharmaceutical Measurement
Basic Calculations Used in Pharmacy Practice
Advanced Calculations Used in Pharmacy Practice 2
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3. Pharmacy Practice, Fourth Edition
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. 3
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4. Pharmacy Practice, Fourth Edition
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. 4
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5. Pharmacy Practice, Fourth Edition
Learning Objectives
Convert temperatures to and from the Fahrenheit and Celsius scales.
Round decimals up and down. 5
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6. Pharmacy Practice, Fourth Edition
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. 6
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7. Pharmacy Practice, Fourth Edition
Learning Objectives
Perform fundamental dosage calculations and conversions.
Solve problems involving powder solutions and dilutions. 7
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8. Learning Objectives Use the alligation method to prepare solutions.
Pharmacy Practice, Fourth Edition
Learning Objectives
Use the alligation method to prepare solutions.
Calculate the specific gravity of a liquid. 8
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9. Systems of Pharmaceutical Measurement
Pharmacy Practice, Fourth Edition
Systems of Pharmaceutical Measurement
The metric system
Common measures
Numeric systems
Time
Temperature 9
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10. Pharmacy Practice, Fourth Edition
The Metric System
Pharmacists and pharmacy techs must make precise measurements daily
Most important measurements are
Temperature
Distance
Volume
Weight 10
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11. Terms to Remember metric system
Pharmacy Practice, Fourth Edition
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 11
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12. Terms to Remember gram liter meter
Pharmacy Practice, Fourth Edition
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 . 12
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13. Pharmacy Practice, Fourth Edition
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 13
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14. Pharmacy Practice, Fourth Edition
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 14
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15. Pharmacy Practice, Fourth Edition
The Metric System
An error of a single decimal place is an error of a factor of 10. . 15
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16. The Metric System 16 Pharmacy Practice, Fourth Edition
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17. The Metric System 17 Pharmacy Practice, Fourth Edition
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18. Common Measures Common measures are approximate.
Pharmacy Practice, Fourth Edition
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. 18
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Pharmacy Practice, Fourth Edition
Common Measures
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20. Pharmacy Practice, Fourth Edition
Common Measures
For safety reasons, the use of the apothecary system is discouraged. Use the metric system. . 20
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21. Common Measures 21 Pharmacy Practice, Fourth Edition .
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22. Common Measures 22 Pharmacy Practice, Fourth Edition
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23. Pharmacy Practice, Fourth Edition
Common Measures
Always carefully check and double-check all calculations. 23
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