Lecture 1: Measuring Equipment

Question 1

What is the selection of a balance based on?

Answer 1

Nature and amount of material to be weighed and the accuracy desired

Question 2

What must every licensed pharmacy have?

Answer 2

A prescription balance

Question 3

What is sensitivity represented by?

Answer 3

Sensitivity requirement

Question 4

What is a sensitivity requirement?

Answer 4

The weight which will cause a specified change

Question 5

What is the minimum SR for a prescription balance?

Answer 5

6 mg

Question 6

What is the normal capacity of a prescription balance?

Answer 6

120 g

Question 7

What can affect electronic balances?

Answer 7

1) Temperature

2) Electromagnetic fields

Question 8

What type of location should a balance be kept in?

Answer 8

On a level solid surface that is free from vibrations, air movement, and dust

Question 9

When must a calibration be done?

Answer 9

When the balance is moved

Question 10

What is the weight that is depicted on an electronic balance?

Answer 10

The force that gravity exerts on a mass

Question 11

_____ varies with altitude

Answer 11

Force of gravity

Question 12

What are 4 rules when working with balances?

Answer 12

1) Material must never be weighed directly on pan
2) Fixed weights must never be touched with fingers
3) Care must be taken to avoid spillage and cross-contamination
4) All materials must be identified at all times

Question 13

What is the acceptable margin of error for pharmaceutical products?

Answer 13

Plus or minus 5%

Question 14

When would an accuracy better than plus or minus 5% be required?

Answer 14

When the therapeutic window for a drug is very small

Question 15

What is accuracy?

Answer 15

The extent to which a measure agrees with the true value

Question 16

What is error of measurement?

Answer 16

The measured value minus the desired value

Question 17

What is the equation for % error?

Answer 17

sensitivity/quantity desired x 100%

Question 18

What is the equation for lowest weighable quantity (LWQ)?

Answer 18

sensitivity/% error tolerated x 100%

Question 19

What is trituration?

Answer 19

The process of grinding a drug in a mortar and pestle in order to reduce particle size or blend powders

Question 20

What does trituration allow for?

Answer 20

Removal of an aliquot which will contain the desired quantity of drug with acceptable accuracy

Question 21

When is geometric dilution used?

Answer 21

When a small amount of material is to be mixed with a much larger amount of solid or semi-solid material

Question 22

What is geometric dilution effective at?

Answer 22

Mixing

Question 23

What are mortars and pestles commonly used for?

Answer 23

Small scale comminution

Question 24

What is comminution?

Answer 24

A mechanical process of reducing particle size

Question 25

What can mortars and pestles be made of?

Answer 25

Glass or porcelain

Question 26

When are glass mortars and pestles used?

Answer 26

Soft powders, liquid incorporation, or semi-solid like ointments

Question 27

When are porcelain mortars and pestles used?

Answer 27

For comminution of crystalline material and for primary emulsions

Question 28

What type of mortar and pestle should be used for coloured materials?

Answer 28

Glass

Question 29

What type of mortar and pestle should be used for volatile oils?

Answer 29

Glass

Question 30

When should a steel spatula NOT be used?

Answer 30

1) When materials could corrode the metal | 2) When trace amounts of metal may be harmful to the product (materials which oxidize easily)

Question 31

What are spatulas primarily used for?

Answer 31

Levigation of powders prior to incorporation into semi-solids

Question 32

What is levigation?

Answer 32

A process of mixing powder with a small amount of liquid in which the powder is insoluble to make a smooth paste

Question 33

What is levigation often done with?

Answer 33

A flexible spatula on a glass slab

Question 34

What must be considered when choosing a levigating agent?

Answer 34

It must be compatible with drug and vehicle

Question 35

What are the 2 most common levigating agents?

Answer 35

Mineral oil and glycerin

Question 36

What is volumetric glassware used for?

Answer 36

Measurement of exact quantities of liquid

Question 37

Are pipettes "to deliver" or "to contain"?

Answer 37

To deliver

Question 38

Are cylindrical graduates "to deliver" or "to contain"?

Answer 38

To contain

Question 39

Are volumetric flasks "to deliver" or "to contain"?

Answer 39

To contain

Question 40

What are examples of glassware that are NOT volumetric?

Answer 40

1) Erlenmeyer flasks 2) Beakers 3) Prescription bottles

Question 41

What are pipettes used for?

Answer 41

To measure volumes smaller than 5 mL

Question 42

What should pipettes be filled with?

Answer 42

A bulb

Question 43

What are graduated cylinders used for?

Answer 43

Measuring and transferring liquids when the volume is greater than 2 mL

Question 44

What is a general rule to use when choosing devices to measure liquids?

Answer 44

The volume being measured must be at least 25% of the capacity