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Introduction to Pharmacy

• This is an introductory course in pharmacy.
• The course is lectured by Rawan Al-Humay, a Master of Industrial Pharmacy.
• The lecture covers fundamental units in pharmacy.

Fundamental Units in Pharmacy (Basic Units)

Length

• Decimeter (dm): 0.100 meter
• Centimeter (cm): 0.010 meter
• Millimeter (mm): 0.001 meter
• Micrometer (µm): 0.000,001 meter
• Nanometer (nm): 0.000,000,001 meter

Volume

• Liter (L): The basic unit of volume. Equivalent to the volume of a cube with a side length of 0.1 m (or 1 dm).
• Deciliter (dm³): 0.100 liter
• Centiliter (cm³): 0.010 liter
• Milliliter (mL): 0.001 liter
• Microliter (µL): 0.000,001 liter

Weight

• Gram (g): The basic unit of weight in the International System of Units (SI). Equals the weight of 1 cm³ of water at 4°C.
• Kilogram (kg): 1000 grams
• Dekagram (dag): 10 grams
• Hectogram (hg): 100 grams
• Centigram (cg): 0.010 gram
• Decigram (dg): 0.100 gram
• Milligram (mg): 0.001 gram
• Microgram (µg): 0.000,001 gram

Examples of Conversions

• 2.525 liters = 2,525,000 microliters
• 9876 milligrams = 9.876 grams
• 85 micrometers = 0.085 millimeters = 0.0085 centimeters

Writing Prescriptions

• In prescriptions, weight is measured in grams and its fractions.
• Volume is measured in milliliters and its fractions.
• When adding ingredients, ensure units are consistent (grams for solids, milliliters for liquids).

Example of Calculation

• A capsule contains 0.075 g, 20 mg, 0.5 mg, 4 mg, and 500 μg. The total weight is 0.1 g or 100 mg.

Additional Units

• 1 inch = 2.54 cm
• 1 meter = 39.37 inches
• 1 pound = 454 grams
• 1 kilogram = 2.2 pounds

Example: Effervescent Tablet

• A tablet has specific proportions of ingredients (Acetaminophen, Calcium Carbonate, Citric Acid, Potassium Bicarbonate, Sodium Bicarbonate).
• Calculations involve determining total weight and potentially calculating the number of tablets that can be made from a given amount of material (e.g., 5 kg of acetaminophen).

Concentration Expressions

• Concentration is expressed either by grams per liter (g/L), grams per milliliter (g/mL), or milligrams per liter (mg/L), milligrams per milliliter (mg/mL)
• Percentage (%): Parts of a substance per 100 parts of the solution. Expressable as fractions (x/100), decimal values (e.g., 0.50 or 0.05).

Types of Percentages

• w/v%: Grams of solute per 100 mL of solution. Examples include Syrups
• v/v%: Milliliters of solute per 100 mL of solution. Examples include alcoholic solutions, perfumes.
• w/w%: Grams of solute per 100 g of solution. Common for creams and ointments.
• Examples include calculating percentage concentrations of solutes.

Other Calculations

• Examples involve determining the amount of dextrose or potassium permanganate required to prepare specific solutions given certain percentages.
• Solutions are calculated using formulas to determine the needed compounds.

Teaspoon/Tablespoon

• Teaspoon (tsp.) = Equivalent to 5 mL
• Tablespoon (tbsp.) = Equivalent to 15 mL
• Measurements may vary slightly depending on the specific utensil.

Additional Examples and Exercises

• These pages contain various types of calculations.
• Common examples of dosage calculations. The examples illustrate how to convert different units and calculate appropriate dosages for patients.

Drop as a Unit

• A drop (gtt) is used to measure small volumes of liquids.
• The size of a drop varies depending on the dropper and the liquid.
• Standard droppers are designed such that 20 drops equal 1 mL.
• Example calculations are demonstrated for calculating drops per milliliter given the volume measured in a particular dropper.