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TABLETSManufacturing, Equipment and Quality Control.Anirban Saha
M.Pharm (Pharmaceutics)Semester- 1Amity University.
AMITY INSTITUTE OF PHARMACY
In early days, most of the tablets required granulation of the powdered Active Pharmaceutical Ingredient (API) and Excipients. At the availability of new excipients or modified form of old excipients and the invention of new tablet machinery or modification of old tablet machinery provided an ease in manufacturing of tablets by simple procedure of direct compression.
Amongst the techniques used to prepare tablets, direct compression is the most advanced technology. It involves only blending and compression. Thus offering advantage particularly in terms of speedy production. Because it requires fewer unit operations, less machinery, reduced number of personnel and considerably less processing time along with increased product stability.
Lubricants To reduce the friction during tablet ejection between
the walls of the tablet and the walls of the die cavity
Glidants Reducing friction between the particles To improve the flow properties of the granulations
Antiadherants To prevent adherence of the granules to the punch
faces and dieso Wetting agents Antioxidants Preservatives Coloring agents Flavoring agents
Direct compression
Dry granulation
Wet granulation
Hopper for holding and feeding granulation to be compressed
Dies that define the size and shape of the tablet Punches for compressing the granulation within
the dies Cam tracks for guiding the movement of the
punches Feeding mechanisms for moving granulation
from the hopper into the dies
Mechanism
Multi-station rotary presses
The head of the tablet machine that holds the upper punches, dies and lower punches in place rotates
As the head rotates, the punches are guided up and down by fixed cam tracks, which control the sequence of filling, compression and ejection.
The portions of the head that hold the upper and lower punches are called the upper an lower turrets
The portion holding the dies is called the die table The pull down cam (C) guides the lower punches
to the bottom, allowing the dies to overfill The punches then pass over a weight-control cam
(E), which reduces the fill in the dies to the desired amount
A swipe off blade (D) at the end of the feed frame removes the excess granulation and directs it around the turret and back into the front of the feed frame
The lower punches travel over the lower compression roll (F) while simultaneously the upper punches ride beneath the upper compression roll (G)
The upper punches enter a fixed distance into the dies, while the lower punches are raised to squeeze and compact the granulation within the dies
After the moment of compression, the upper punches are withdrawn as they follow the upper punch raising cam (H)
The lower punches ride up the cam (I) which brings the tablets flush with or slightly above the surface of the dies The tablets strike a sweep off blade affixed to the front of the feed frame (A) and slide down a chute into a receptacle
At the same time, the lower punches re-enter the pull down cam (C) and the cycle is repeated
Multi Station Rotary Press.
Principle- Multi Station Rotary Press.
Although tablet compressing machinery has undergone numerous mechanical modifications over the years, the compaction of materials between a pair of moving punches within a stationary die has remained unchanged.
Special adaptations of tablet machines allow for the compression of layered tablets and coated tablets.
Coating/Polishing:What are the problems
What are the equipment
Why do it
Blistering, chipping, cratering, picking, pitting
Color variation
Roughness
Pan (standard/perforated) Coating Machines
Fluidized Bed Coating Machines
Spray Coating Machines
Vacuum, Dip & Electrostatic Coating Machines
Enhance appearance and colour
Mask taste and odour (film/sugar)
Improve patient compliance
Improve stability
Impart enteric, delayed, controlled release properties
Tablet Coating Machines
In-process Checks :-
Parameter Frequency
Wt. of 20 tabs Every hour by production and every two hours by QA
Hardness, thickness, length, width Every hour by production, every two hours by QA
Wt. variation Every half hour by production and every hour by QA
DT Every half hour by production, every hour by QA
Mixing of granulation blend
GranulationBinder(s)
Preparation of binder solution
Drying
Milling
In Process Testing
Disintegrant
screening
screeningInitial Blending
lubricant screening Final Blending
Compression
SolventFilm coating agent Preparation
Film Coating of Tablets
WeightHardnessFriability
Complete Process :
Packaging and Labelling
Quality Control of Tablets
General Appearance:-Size, shape, and thickness: This is important to facilitate packaging
and to decide which tablet compressing machine to use.
-Organoleptic properties: which include color and odor of the
tablets.
Official Standards as per I.P Uncoated tablet:-Uniformity of container content-Content of active ingredient-Uniformity of weight-Uniformity of content-Disintegration test
Enteric coated tablet:-Disintegration test
Dispersible tablet:-Uniformity of dispersion-DisintegrationSoluble tablet:-Disintegration testEffervescent tablet:-Disintegration/ Dissolution / Dispersion
test
Official and unofficial tests: Non official tests:
Hardness (crushing strength): It is the load required to crush the tablet
when placed on its edge.
Factors Affecting the Hardness: Compression of the tablet and compressive
force. Amount of binder. (More binder ,more
hardness) Method of granulation in preparing the
tablet.
Friability: It is the tendency of tablets to powder, chip
or fragment and this can affect the elegance appearance, consumer acceptance of the tablet, and also add to tablet’s weight variation or content uniformity problems.
An instrument called friabilator is used to evaluate the ability of the tablet to withstand abrasion in packaging, handling, and shipping.
Procedure:1. Weigh 20 tab altogether = W1 2. Put these tablets in the friabilator and
adjust the instrument at 100 rpm
3. Weigh the 20 tablets (only the intact ones) = W2
4. Friability (% loss) = It must be less than
or equal to1% . But if more we do not reject the tablets as
this test is non-official.
Friabilator
Thickness Test :o Thickness is an unofficial test .
o Thickness of the tablet is inversely proportional to hardness
i.e. increase in hardness decrease the thickness & vice
versa.
o Thickness of tablet is measured by Vernier caliper.
o It is determined for 10 tablets. Vernier Caliper
Official Tests:Disintegration: It is the time required for the tablet to break
into particles, the disintegration test is a measure only of the time required under a given set of conditions for a group of tablets to disintegrate into particles.
The time of disintegration is a measure of the quality. This is because, for example, if the disintegration time is too high; it means that the tablet is too highly compressed or is not of pharmacopoeial quality.
Liquids used in disintegration : Water, Simulated gastric fluid (PH = 1.2 HCl), or Simulated intestinal fluid (PH = 7.5)
KH2PO4 (phosphate buffer) + enzyme +NaOH)
Disintegration Apparatus
Limits(Uncoated tablets) :
Medium Temperature Time limit
According to U.S.P.
Simulated gastric fluid
37°C Not exceed 30min
According to B.P.
water 37°C Not exceed 15min
Limits(Coated):
Weight Variation (Uniformity of weight) of tablets:
1. Weigh 20 tablet selected at random, each one individually . X1, X2, X3… Xz
2. Determine the average weight. X= (X1+X2 +X3+…+ X20)/20
Limits Weight of tablet 130 mg or less then
%error = ±10% · Weight of tablet 130-324 mg then
%error = ±7.5% · Weight of tablet 324 mg or more then
%error = ±5%
Dissolution TestDissolution is performed to check the percentage release
from the dosage forms i.e.tablet.
Tablet breaks down into small particles which offers a greater
surface area to the dissolving media.
Disintegration test does not give assurance that particles will
release drug in solution at an appropriate rate, that’s why
dissolution tests & it’s specifications developed for all tablet.
Dissolution Apparatus
TYPES OF DISSOLUTION APPARATUS :
1. USP Dissolution apparatus I ( Basket method)
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.
USP Dissolution Apparatus I
2. USP Dissolution apparatus II ( Paddle method)
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 test tolerance is
expressed as % of the labeled amount of drug dissolved in the time
limit. USP Dissolution Apparatus II
Dissolution testing and interpretation IP standards
Pharmaceutics. The science of dosage forms design. (M.E. Aulton)
Leon Lachman, The theory and practice of Industrial Pharmacy,3rd edition, page no.67-68,77-78,315-317,296-303.
Indian Pharmacopoeia-2010,Govt.Of India ministry of health & family welfare,6th edition.
References
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