Lab 5: Evaluation Of Tablets

Question 0

How is the general appearance of a tablet evaluated?

Answer 0

By visual observation, taking into account
the tablets
Shape (e.g. Spherical, oblong, almond shaped, heart shaped)
colour (e.g. White, off white)
surface (e.g. Smooth, rough, shiny)
Odour (e.g. Vinegar, mint)

Question 1

Why do we need to do quality control evaluations on tablets?

Answer 1

There are various properties of tablets which can undergo change due to environmental or stress conditions. This will affect their bioavailability

Question 2

What is the general appearance of panadol tablets ?

Answer 2

Spherical, white tablets with. Smooth surface.

Odourless

Question 3

How is the uniformity of size test evaluated?

Answer 3

By measuring the diameter and thickness of 20 individual tablets single an electronic Vernier Caliper.
The individual and average values are recorded.

Question 4

Why is hardness of tablets evaluated?

Answer 4

This test helps to determine the resistance to crushing of tablets as during their shipping and handling they will be subjected to physical stress.

Question 5

How is the hardness test evaluated?

Answer 5

By measuring the force required to crush the tablet (vertically) i.e. Applying the force through the diameter of the tablet.

This is done using a Monsanto hardness tester.

10 tablets are evaluated and their individual and average values are recorded.

Tablets must be a minimum of 4kg/cm^2

Question 6

Why is the friability test conducted?

Answer 6

This measures the ability of the tablet to be easily crumbled or reduced to a powder.
This is designed to evaluate the ability of the tablet to withstand abrasion in packaging, handling and shipping

Question 7

How is the friability test conducted?

Answer 7

If the tablet unit mass is 650mg, 10 tablets are evaluated.

The sample of tablets are weighed, and then placed in the friability unit which rotates 100 times at 25rpm. The loose dust is removed and the tablets are re weighed.
There should not be more than 1% of mass loss.
Cracked or broken tablets = fail.
If difficult to assess samples, take the mean of 3 measurements

Question 8

How is the uniformity of weight evaluated?

Answer 8

20 tablets are weighed individually to determine the average mass using an electronic balance.
Deviations from the average is calculated in %s

The panadol tablets were >250mg, so BP specifies no more than 2 should deviate by more than 5%, and none should deviate by more than 10%

Question 9

When is uniformity of content tested?

Answer 9

Then the average mass is less than or equal to 40mg

Question 10

Why is the disintegration test conducted?

Answer 10

To determine whether tablets or capsules disintegrate within the prescribed time when placed in a liquid medium under specific environmental conditions

Question 11

What is classified as complete disintegration?

Answer 11

When the residue of the unit remaining on the screen of the test apparatus or adhering to the lower part of the disc is a soft mass having no firm core

Question 12

How is the disintegration test conducted?

Answer 12

6 tablets are dropped at the same time in the disintegration apparatus (1 tablet in each tube)
The discs are placed on top of each tablet in each tube.
The apparatus is set to operate at 37°C +/- 2°C
If non enteric coated, all tablets should disintegrate complete.
If more than 1 fails to do so, the test should be related on 12 additional tablets and 16/18 of the tablets should have disintegrated.

Question 13

Why is evaluating the general appearance of size, shape and thickness of tablets important?

Answer 13

To facilitate packaging and to decide which tablet compressing machine to use

Question 14

Why is determining the organoleptic properties (including colour and odor), of a tablet important?

Answer 14

This is a vital means of identification of many pharmaceutical tablets and is also usually important for consumer acceptance.

Question 15

What are the acceptable ranges of colour in a batch of tablets?

Answer 15

Colour should be uniform within a single tablet, from tablet to tablet and from batch to batch

Question 16

What are the acceptable variances in odour of tablets?

Answer 16

Odour provides an indication of the quality of tablets as presence of an odour could suggest a stability problem e.g. The characteristic odor of acetic acid in degrading aspirin tablets.

The presence of an odour may also be characteristic of the drug e.g. Vitamins, added ingredients e.g. Flavouring agent, or the dosage form e.g. Film coated tablets

Question 17

What are the quality control tests?

Answer 17

Weight uniformity and content uniformity
Dissolution test
Weight variation, thickness and diameter
Hardness and friability

Question 18

Why is weight uniformity and content uniformity tested?

Answer 18

Tablets should include the correct dose of drug

Question 19

Why is dissolution tested?

Answer 19

Drug should be released from tablet in a controlled and reproducible way

Question 20

Why is weight variation, thickness and diameter tested?

Answer 20

Appearance of tablet should be elegant.

Its weight, size and appearance should be consistent

Question 21

Why is hardness and friability tested?

Answer 21

Tablet must show sufficient mechanical strength to withstand fracture and erosion during manufacture and handling.

These factors must be controlled during production and verified after production i.e. In process control

Question 22

What is tablet weight affected by?

Answer 22

Factors such as
Head pressure of compression machine
Machine speed
Flow properties of the powder.

Question 23

What is hardness?

Answer 23

The load required to crush the tablet when placed on its edge

Question 24

Why is hardness measured?

Answer 24

To determine the pressure adjustments on the tableting machine

Hardness affects disintegration, if tablet is too hard it may not disintegrate in the required period of time.
If tablet is too soft it will not withstand handling during subsequent processes such as coating and packaging

Question 25

What happens if the tablet hardness is too high?

Answer 25

First we check its disintegration before rejecting the batch.
If the disintegration is within its limits we can ac pet the batch

Question 26

What factors affect the hardness of tablets?

Answer 26

Compression of tablet
Compressive force
Amount of binder (more binder increases the hardness)
Method of granulation in preparing tablet (wet method gives more hardness)
Limit: min 4kg/cm^2 as the average of 10 readings

Question 27

What is friability?

Answer 27

The tendency of tablets to powder, Chip or fragment.
This can affect the elegance, appearance, consumer acceptance.

It also adds to the tablets weight variation or content uniformity problems

Question 28

What is friability related to?

Answer 28

The hardness of the tablet,
Its weight variation
And the content uniformity

Question 29

What is the instrument used to measure friability?

Answer 29

A friabilator is used to evaluate the ability of the tablet to withstand abrasion in packaging, handling and shipping.

In this unit the tablet is subjected to a tumbling motion

Question 30

What is another application of the friability test?

Answer 30

To detect capping or laminate when tablets are subjected to stress inside the rotating cylinder present in the friability tester

Question 31

What is capping?

Answer 31

The partial or complete separation of the top or bottom crown from the main body of the tablet

Question 32

What is lamination?

Answer 32

The separation of the tablet into two or more distinct layers

Question 33

What is disintegration?

Answer 33

The time required for the tablet to break into particles

The disintegration test is a measure of the time required under a given set of conditions for a group of tablets to disintegrate into particles

Question 34

How is the disintegration test different in the evaluation of un coated tablets?

Answer 34

The apparatus is operated for 15 minutes,
If tablets fail to comply due to adhering to the discs, the results are invalid and the test must be repeated on a further 6 tablets without the discs

Question 35

How is the disintegration test different for coated tablets?

Answer 35

The apparatus is operated for 60min or 30min for film coated tablets.
If any of the tablets have not disintegrated, the test is repeated on 6 more tablets and the water is replaced with 0.1M HCl

Question 36

How is the disintegration test different when evaluating effervescent tablets?

Answer 36

ONE tablet is placed in a beaker which contains 200mL of water at 15-25°C
When the evolution of gas around the tablet or its fragment ceases, the tablet has disintegration
This is then repeated on 5 other tablets.

Tablets are said to comply if each of the 6 tablets used disintegrate in the manner prescribed in 5mkns