1. Pharmacy Units Measurements and Abbreviations There are others in the Student Handout book The most common ones (Must know) C=Celsius F =Fahrenheit G or gr =Gram Gr. = grain L= liter Ml= Milliliter Mg=Milligram Kg=Kilogram TBSP= tablespoon TSP= Teaspoon Gtt= drop

2. Measurement Systems Metric System- began in France in 1795. Denotes basic units of measurement in 6 main areas: Mass - Gram Length- meter Time- second Volume- liter Electricity- Ampere (named after the french mathematician, Andre Marie Ampere) is a unit of electric current. Temperature – Kelvins Conversions are made based on factors of ten:

3. Metric System is the preferred system in science and medicine due to its factor of ten basis. Used in most countries in the world Prefix and meaning Pico= 0.000000000001 (trillionth) Nano =0.000000001 (billionth) Micro = 0.000001 (millionth) Milli =0.001 (thousandth) Centi=0.01 (hundredth) Deci = 0.1 (tenth) Kilo=1,000 (thousand)

4. Visual method to conversion between Metric units Think of a “staircase method” with each prefix as a step Each step represents a factor of 1000 As you climb the steps you “expend energy” and you lose 3 zero’s each step As you descend the steps you “add energy” and you gain 3 zero’s each step Thus 1,000,000,000 nanograms= 1,000,000 micrograms= 1,000 milligrams = 1 gram. N= any number 1,000,000,000 N Nanograms 1,000,000, N micrograms 1,000 N milligrams 1 N Gram

5. Using the staircase method How many mcg are in 2 mg? You are descending the staircase so you add 3 zeros t0 2 mg to get 2,000 mcg, so 2 mg is 2,000 mcg 2 mg 2,000 mcg

6. Mathematical method of Metric System Conversions How many micrograms are in 2 mg? You know that 1,000 micrograms= 1 mg 1,000 mcg/ 1 mg = x mcg/ 2 mg Eliminate the unit to see the ratio numbers 1,000/1 = x/2 Cross multiply X= 1,000X2 X= 2,000 X= 2,000 mcg

7. US Customary Units and British Imperial Systems Development over centuries in the British Isles and later in the US colonies Formally standardized in 1824 Still use in the US and Great Britain Today; however, almost all scientific applications use the metric system or the SI system (Système international d'unités ) Avoirdupois system is a subsystem of weights in the US and British Systems based on the pound.

8. The follow is a list of weights and their metric equivalents 1 Grain = 65 mg (5 gr aspirin =325 mg) exception: 1 gr of thyroid, phenobarbital, codeine and nitroglycerin) is 60 mg 1 lb (pound) = 16 ounces 1 ounce = 28.55 grams 1 fl. Oz= 28.55 ml (remember 30 ml) 2.2 pound = 1 kilograms 1 Dram (symbolized by ʒ ) = 3.9 g and 1 f ʒ = 3.9 ml 1 pint= 16 fl ounces 2 pints= 1 quart and 1 quart = 960 ml or about 1 liter 4 quarts = 1 gallon

9. Household measurements 1 tsp = 5 ml 1 tbsp= 15 ml 1 cup = 8 ounces or 240 ml 20 gtts = 1 ml (use to calculate the number of drops in eye drop products ) 5 ml is how many drops? 20 drops/ 1 ml = x drops/ 5 ml X= 20 X5 X= 100 drops

10. Apothecary System Apothecary system is a system of weights and measure used in Europe during the 18 th century by physicians and pharmacist (apothecary) Is a subset of the British Imperial systems The following are important to remember in pharmacy The only difference between apothecary system and Avoirdupois system is the troy ounce is heavier than the avoirdupois ounce. the troy ounce which is the 31.1 grams instead of 28.55 grams Precious metals and gemstones are weighted in troy ounces. Gold=Au, Silver= Ag, Platinum = Pt