What is a Tablet?
• Tablet is defined as a compressed solid dosage form containing
medicaments with or without excipients.
• According to the Indian Pharmacopoeia Pharmaceutical ,tablets are
solid, flat or biconvex dishes, unit dosage form, prepared by
compressing a drug or a mixture of drugs, with or without diluents.
• The excipients can include diluents, binders or granulating agents,
disintegrants, sweeteners or flavours and pigments.
Diluents are fillers used to make required bulk of the tablet when the drug
dosage itself is inadequate to produce the bulk. Ex.- Lactose, Sorbitol.
These materials are added either dry or in wet- form to form granules or
to form cohesive compacts for directly compressed tablet. Ex. - Acacia,
Lubricants are intended to prevent adhesion of the tablet materials to the
surface of dies and punches, reduce inter particle friction and may
improve the rate of flow of the tablet granulation. Ex. - Stearic acid,talc.
Added to a tablet formulation to facilitate its breaking or disintegration
when it contact in water. Ex. - Starches are the most common
The use of colours and dyes in a tablet has two purposes:
(1) Product Identification
(2) Production of more elegant product
Ex.- D&C and FD&C dyes and lakes
Flavors and Sweeteners:
To enhance taste and make tablets visually attractive.Ex. – sucrose,
Adavantages Of Tablet :
• Lighter and compact.
• Easiest and cheapest to package and strip.
• Suitable for large scale production.
Disadvantages Of Tablet :
• Difficult to swallow in case of children and unconscious patients
• Bitter tasting drugs, drugs with an objectionable odor or drugs that
are sensitive to oxygen may require encapsulation or coating.
There are three methods of preparing tablet granulations.
a) Wet granulation
b) Dry granulation (also called "slugging")
c) Direct compression.
Wet Granulation :
The most popular method (over 70% )
Granulation is done
• To prevent segregation of the constituents of the powder blend.
• To improve flowability of the powder mixture.
• To improve homogeneity and thus ensure content uniformity
• The dry granulation process is used to form granules without using a liquid
• In this process, the primary powder particles are aggregated under high
• Direct Compression is the simplest form of oral dosage
production as it contains the fewest process stages, leading to a
shorter process cycle and faster production times.
• The ingredients are weighed, blended and then compacted
directly following lubrication.
An instrument used to sieve the ingredients of a tablet with a
replaceable mess ware. In this technique, particles of powder mass
are placed on a screen made of uniform aperture. The sifter is
attached with a vibrator that helps in sieving the materials through the
Solutions of the binding agent are added to the mixed powders
with stirring. The planetary mixer can mix a material of 100kg.
The beater of the planetary mixer revolves 2-4times for each
revolution of the head, providing double mixing action.
This is also mixing equipment used to mix dry as well is wet
ingredients. The mixer has blades that are alternately arranged
and is allows uniform mixing.
The mass mixer is emptied by inverting it and scrapping off its
This is a hammer mill that uses a high speed rotor to which a number
of swinging hammers are fixed. The unit is enclosed with chamber
containing a grid or removable screen through which the material can
pass. The material is fed from the top and ground by impact of
hammers or against the plates around the periphery of the casing.
It consists of a chamber, containing horizontal arrangements of trays on
which granules are dried. The drying process is accomplished by a gust
of hot air driven by or blower through an electric heater and heat
The basic unit of any tablet press is a set of tooling consisting of two
punches and a die which is called a station. The die determines the
diameter or shape of the tablet; the punches, upper and lower, come
together in the die that contains the tablet formulation to form a tablet.
There are two types of presses:
The single-punch press has a single station of one die and two punches,
and is capable of producing from 40 to 120 tablets per minute depending
on the size of the tablet.
The rotary press has a multiplicity of stations arranged on a rotating table
in which the dies are fed the formulation producing tablets at production
rates of' from a few to many thousands per minute.