Transcript 322_PHT_ Tablet _evalu..

Tablet evaluation test
322 PHT
Nahla Barakat, PhD
King Saud University
Dept. of Pharmaceutics
1431/1432
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 The quantitative evaluation and assessment of a tablet‘s
chemical, physical and bioavailability properties are important
in the design of tablets and to monitor product quality.
 These properties are important since chemical breakdown or
interactions between tablet components may alter the physical
tablet properties, and greatly affect the bioavailability of the
tablet system.
 There are various standards that have been set in the various
pharmacopoeias regarding the quality of pharmaceutical
tablets.
 These include the diameter, size, shape, thickness, weight,
hardness, disintegration and dissolution characters.
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 General Appearance
The general appearance of a tablet, its identity and general
elegance is essential for consumer acceptance, for control of
lot-to-lot uniformity and tablet-to-tablet uniformity.
 The control of general appearance involves the measurement of
size, shape, color, presence or absence of odor, taste etc.
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 Organoleptic properties
 Color is a vital means of identification for many pharmaceutical tablets and is also
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usually important for consumer acceptance.
The color of the product must be uniform within a single tablet, from tablet to tablet
and from lot to lot.
Reflectance spectrophotometry, tristimulus colorimetric measurements and micro
reflectance photometer have been used to measure color uniformity and gloss on a
tablet surface .
Odor may also be important for consumer acceptance of tablets and can provide an
indication of the quality of tablets as the presence of an odor in a batch of tablets
could indicate a stability problem, such as the characteristic odor of acetic acid in
degrading aspirin tablets.
Taste is also important for consumer acceptance of certain tablets (e.g. chewable
tablets) and many companies utilize taste panels to judge the preference of different
flavors and flavor levels in the development of a product.
Taste preference is however subjective and the control of taste in the production of
chewable tablets is usually based on the presence or absence of a specified taste.
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 Size & Shape
It can be dimensionally described & controlled.
 The thickness of a tablet is only variables.
 Tablet thickness can be measured by micrometer or by
other device.
 Tablet thickness should be controlled within a ± 5%
variation of standard value.
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 Weight Variation test (U.S.P.)
Take 20 tablet and weighed individually.
 Calculate average weight and compare the individual
tablet weight to the average.
 The tablet pass the U.S.P. test if no more that 2 tablets
are outside the percentage limit and if no tablet differs
by more than 2 times the percentage limit.
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Average weight
Percent difference
 130mg or less
10
 More than 130mg through 324mg
 More than 324mg
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 The content uniformity test
 is used to ensure that every tablet contains the amount of
drug substance intended with little variation among tablets
within a batch.
 the content uniformity test has been included in the
monographs of all coated and uncoated tablets and all
capsules intended for oral administration where the range
of size of the dosage form available include 50mg or
smaller sizes.
 Tablet monographs with a content uniformity requirement
do not have weight variation requirements.
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 Content Uniformity Test:
 Randomly select 30 tablets.
 Ten of these assayed individually.
 The Tablet pass the test if 9 of the 10 tablets must contain
not less than 85% and not more than 115% of the labeled
drug content and the 10th tablet may not contain less than
75% and more than 125% of the labeled content.
 If these conditions are not met, remaining 20 tablet
assayed individually and none may fall out side of the 85
to 115% range.
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 Hardness (Fracture-resistance test):
 Tablets require a certain amount of strength or hardness. Why?
 1. Withstand mechanical shocks of handling in manufacture,
packaging and shipping.
 2. Withstand reasonable abuse when in the
hands of the consumer.
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 3. The relationship of hardness to tablet
disintegration, dissolution .
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 Tablet Hardness: the force required to break a tablet along its
diameter by applying compression loading.
Test Description:
 A tablet is placed between two anvils, force is applied to the anvils, &
the crushing strength that just causes the tablet to break is recorded
(in kg).
 Hence, Hardness is thus sometimes termed the tablet crushing
strength.
 Tablet hardness should be between 5 – 8 kg
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 Hardness Variation:
 It depends on:
 - compression force,
 - concentration and type of binding agent
If the tablet initially is too hard, it may not disintegrate
in the requisite period of time.
 If it is too soft, it may not withstand the necessary
multiple shocks occurring during handling, shipping, and
dispensing.
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 Friability (attrition-resistance test):
 It's another measure of a tablet's strength.
 Why measure friability?
 Tablets that tend to powder& fragment when handled:
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lack elegance & consumer acceptance,
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Create excessively dirty processes in areas of manufacturing as
coating & packaging.
 3.Can also add to a tablet's weight variation or content uniformity
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 The laboratory friability tester is known as the
 Roche friabilator.
 It subjects a number of tablets to the combined effects of
abrasion & shock
 by utilizing a plastic chamber that revolves at 25 rpm,
dropping the tablets with each revolution.
 A preweighed tablet sample is placed in the friabilator,
which is then operated for 100 revolutions.
 The tablets are reweighed.
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 Tablets are then dusted and reweighed.
 Conventional compressed tablets that lose less than 1.0% of
their weight are generally considered acceptable.
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% friability = (W0 – Wf / W0) x %.
 W0 = initial weight,
Wf = final weight.
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 Disintegration Test (U.S.P.):
The U.S.P. device to test disintegration uses 6 glass tubes that
are 3” long; open at the top and 10 mesh screen at the bottom
end.
 To test for disintegration time, one tablet is placed in each tube
and the basket rack is positioned in a 1-L beaker of water,
simulated gastric fluid or simulated intestinal fluid at 37 ± 0.5
C such that the tablet remain 2.5 cm below the surface of liquid
on their upward movement and not closer than 2.5 cm from the
bottom of the beaker in their downward movement.
 Move the basket containing the tablets up and down through a
distance of 5-6 cm at a frequency of 28 to 32 cycles per minute.
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 Floating of the tablets can be prevented by placing
perforated plastic discs on each tablet.
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According to the test the tablet must disintegrate and all
particles must pass through the 10 mesh screen in the time
specified.
 If any residue remains, it must have a soft mass.
 Disintegration time:
 Uncoated tablet: 5-30 minutes
Coated tablet: 1-2 hours
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 Dissolution is the process by which a solid solute
enters a solution. In the pharmaceutical industry, it
may be defined as the amount of drug substance that
goes into solution per unit time under standardized
conditions of liquid/solid interface, temperature and
solvent composition.
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 Dissolution is considered one of the most important
quality control tests performed on pharmaceutical
dosage forms and is now developing into a tool for
predicting bioavailability, and in some cases, replacing
clinical studies to determine bioequivalence.
Dissolution behavior of drugs has a significant effect
on their pharmacological activity. In fact, a direct
relationship between in vitro dissolution rate of many
drugs and their bioavailability has been demonstrated
and is generally referred to as in vitro-in vivo
correlation, IVIVC
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 Apparatus-1 (Basket Type): A single tablet is placed in a
small wire mesh basket attached to the bottom of the
shaft connected to a variable speed motor. The basket
is immersed in a dissolution medium (as specified in
monograph) contained in a 1000 ml flask. The flask is
cylindrical with a hemispherical bottom. The flask is
maintained at 37±0.50C by a constant temperature
bath. The motor is adjusted to turn at the specified
speed and sample of the fluid are withdrawn at
intervals to determine the amount of drug in
solutions.
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 Apparatus-2 (Paddle Type ): It is same as apparatus-1,
except the basket is replaced by a paddle.
 The dosage form is allowed to sink to the bottom of
the flask before stirring.
 For dissolution test U.S.P. specifies the dissolution test
medium and volume, type of apparatus to be used,
rpm of the shaft, time limit of the test and assay
procedure for the API.
 The test tolerance is expressed as a % of the labeled
amount of drug dissolved in the time limit.
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PACKAGING:
Blister Packs
THERMOFORM BLISTERS
 – plastic base web
 – blister formed with aid of heating
 – low to high barrier
 – E.g. PVC
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 COLD FORM BLISTER
 – blister formed mechanically
 (no heat)
 – high barrier
 – E.g. Aluminium foil
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 TROPICALSIDE BLISTER
 – thermoform blister plus cold form tray
 – high barrier before use
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Thanks My Dear Students
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