Evaluation Of Tablet
Introduction
Tablets:-
Tablets are the solid unit dosage forms containing a medicament or mixture of medicament
& excipients compressed or moulded into solid.
TYPE OF TABLETS
I) Compressed tablets
Ex: Coated & Uncoated tablets.
II) Molded tablets
Ex: Dispensing & Hypodermic tablets
Evaluation test of tablet
Non Official Test
1. General Apperance
a) Organoleptic properties
b) Size And Shape
2. Hardness
3. Friability
Official Test
1. Weight Variation
2. Content Uniformity
3. Dissolution
4. Disintegration
Non Official Test
1.The general appearance
The general appearance
of a tablet, its visual identity and overall “elegance”
is essential for consumer acceptance, for control of
lot-to-lot uniformity
Appearance of a tablet involved the measurements
of a tablet’s
• Size
• Shape
• Colour
• Odour
• Taste
• Surface texture
a) Organoleptic properties
• Many pharmaceutical tablets use color as a
vital means of rapid identification and
consumer acceptance
• The color of a product must be uniform
within a single tablets
b) Size And Shape
Measured By :
• Micrometre
• Slider Caliper Scale
Tablet Thickness Should be Controlled Within ± 5 % Variation Of Standard Value
More likely to Cause Capping Problem
2. Hardness
• Tablets require a certain amount of strength, or
hardness and resistance to friability, to withstand mechanical shocks of handling in manufacture, packing and shipping
• Hardness thus sometimes termed the tablet
crushing strength
- Tablet hardness tester are:-
- Monsanto tester
- Pfizer tester
- Strong-cobb tester
- Erweka tester
- Scleuniger tester
3. Friability
• The friability test is official in USP but not in BP
and IP.
• Friability tester is known as the Roche friabilator
.
• Tablet hardness is not an absolute indicator
of strength since some formulations,when
compressed into very hard tablets
.
Procedure
• A number of tablets (20 Nos.) are weighed and placed in the apparatus where they are exposed to rolling and repeated shocks as they fall 6 inches in each turn within the apparatus.
• After 4 minutes of this treatment or 100 revolutions the tablets are weighed and the weight compared with initial weight.
• The loss due to abrasion is a measure of tablet friability.
• The value is expressed in percentage.
• Minimum weight loss of the tablet should not be NMT 1%.
• There should not be any broken tablet.
Official Test
1. Weight Variation.
• The weight of the tablet being made is
routinely measured to help ensure that a tablet Ccontains the proper amount of drug
• As per indian pharmacopoeia (IP)
weight 20 tablets selected at random and
determine the average weight not More Than 2 of the individual weights deviate from the average weight by more than percentage deviation show in The Table
 |
| Weight Variation Chart |
2. Content Uniformity
• The potency of tablets is expressed in the
terms of grams, milligrams, or micrograms of
drug per tablet and is given as the label
strength of the product
.
• Determine the amount of active ingredient by the
method in the Assay.
• The result lies within the range for the content of active ingredient stated in the monograph.
• This test is applicable to tablets that contain
less than 10mg or less than 10% w/w of the
active ingredient
• It is not applicable to tablets containing
multivitamin and trace element
As Per IP
• Ten tablets are taken at random, there
content of active ingredient is determine in
each of 10 tablets and the average value is
calculated
👇
The sample passes the test is not more than one of
the individual value is the out side the limit of 85 to 115% of the average value And none is the outside the limit 75 to 115% of the Average Value
👇
The test is repeated using another
20 tablets In the total sample of 30 tablets
Not more than three of the individual values
are outsides the limit 85 to 115% and none is
outside the limits 75 to 125% of the average
value
3. Dissolution
Definition:
• Dissolution is a process in which a solid substance solubilizes in a given solvent i.e. mass transfer from the solid surface to the liquid phase.
Dissolution is the rate determining step for hydrophobic, poorly aqueous soluble drugs.
E.g. Griseofulvin, spironolactone
Why dissolution studies?
1. To show that the release of drug from the tablet is close to 100%
2. To show that the rate of drug release is uniform batch to batch.
3. And to show that release is equivalent to those batches proven to be bioavailable and clinically effective.
Mechanism of Dissolution
1. Diffusion layer model
2. Danckwert's model
3. Interfacial barrier model
4. Disintegration
This test is provided to determine whether tablets or capsules disintegrate within the prescribed time when placed in a liquid medium under the experimental conditions stated below.
Procedure
Place one dosage unit in each of the six tubes of the basket and if specified add a disc.
Operate the apparatus using water as the immersion fluid unless another liquid is specified and maintain its temperature at 35–39 °C.
At the end of the specified time lift the basket from the fluid and observe the dosage units, all of the dosage units have disintegrated completely.
If one or two dosage units fail to disintegrate repeat the test on 12 additional dosage units. The requirements of the test are met if not less than 16 of the 18 dosage units tested are disintegrated.
Disintegration testing condition and interpretation (USP)
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| Tablet Evaluation Test |
