PHARMACEUTICAL MEASUREMENTS P1

Q: What was the historical standard unit of weight in the Apothecaries' system?

A: Historically, grains (gr) were the standard unit of weight in the Apothecaries' system.

Q: What is the internationally recognized decimal system of weights and measures?

A: The internationally recognized decimal system of weights and measures is the SI (Système International d'Unités), formerly known as the metric system.

Q: What are the base units of the SI system mentioned in the lecture?

A: The base units of the SI system are the meter and kilogram.

Q: What is the metric conversion for 1 grain?

A: A rational metric conversion for 1 grain is 0.06479 grams.

Q: What is the rule for changing a metric denomination to the next smaller denomination?

A: To change a metric denomination to the next smaller denomination, move the decimal point one place to the right.

Q: Name the four main classes of weighing equipment and their approximate range mentioned in the slides. A: The classes and their typical ranges are:

• Class I: Semi micro balance (5 µg - 500 gram), micro balance (2 mg - 20 g)

• Class II: 100 mg - 100 g (often dispensing balances)

• Class III: 1.0 g – 2.0 kg (Top load, Precision, and all other weighing equipment)

Q: What are the minimum and maximum weighable quantities for a Class II balance?

A: The minimum weighable quantity is 100 mg, and the maximum weighable quantity is 25 g.

Q: What is the required minimum amount to be weighed for a potent substance on a pharmacy balance?

A: The minimum amount to be weighed for a potent substance is 100 mg.

Q: How does the scale pan of an electronic balance typically differ from a Class II beam balance?

A: The scale pan on an electronic balance is usually made of metal, while the pan for the ingredient on a Class II beam balance is typically made of glass.

Q: On a Class II Dispensing Beam Balance, where are the weights and the ingredient placed?

A: The weights are placed on the metal pan (on the left), and the ingredient being weighed is placed on the glass pan (on the right).

Q: Why do you press the zero/tare button on an electronic balance during the weighing procedure?

A: The zero/tare button is pressed to zero the balance after placing a weigh boat or container on the pan, allowing only the ingredient's weight to be measured.

Q: What are the two main types of measuring vessels used within pharmacy for measuring liquids?

A: The two main types of measuring vessels are Cylinder/Conical measures and Syringes.

Q: For volumes less than 1 mL, what measuring device is typically used?

A: A syringe is used for volumes less than 1 mL (up to 5 mL)

Q: When reading the volume of a liquid in a graduate (like a conical measure), what must be in alignment to minimize errors caused by the parallax effect?

A: The graduation mark, the meniscus of the liquid, and the line of sight should be in alignment.

Q: What is an oral syringe used for?

A: An oral syringe is a measuring instrument used to accurately measure doses of liquid medicine which are expressed in milliliters (mL).