3. INTRODUCTION:
A Tablet is a solid dosage form, which is administered by the
oral route. It comprises of a mixture of medicaments i.e the
active substance and the suitable pharmaceutical excipient
usually in powdered form. It is compacted and pressed from
the powdered form to the solid dosage form.
4. History of tablet:
If we talk about history of solid tablets , up till 4000 BC ,
people used to administer liquid medicines in the form of
extracts or oils. In the era of Ebers Papyrus they first
introduced the concept of clay tablet. The first reference was
from bread dough , honey or grease. Medicinal ingredients,
such as plant powders or spices, were mixed in and formed by
hand to make little balls, or pills. In ancient Greece, such
medicines were known as katapotia ("something to be
swallowed"), and the Roman scholar Pliny, who lived from
23-79 AD, first gave a name to what we now call pills, calling
them pilula.
5. Types of tablets:
Compressed tablets:
Those tablets which are simply made
by the compressive force
Sugar coated tablet:
Those tablets which are coated by
sugars. The purpose of sugar
coating is to mask the taste of drug
which may be bitter or somewhat
unpalatable. This coating also
protect the drug inside.
6. Enteric coated tablet:
The polymer barrier dosage form that are
designed to extend the release of dosage form.
These kind of dosage forms do not release in
the gastric environment.
Effervescence tablet:
Those tablets which are prepared by
compressing granular effervescent salts that
release gas when in contact with water. These
tablets generally contain medicinal substances
that dissolve rapidly when added to water.
7. Film coated Tablets:
Those tablets which are compressed and coated
with a thin layer of polymer capable of forming a
skin like film. The film is usually colored and has
the advantage over sugar coatings in that it is
more durable, less bulky, and less time
consuming to apply.
Chewable tablets:
Chewable tablets have a smooth, rapid
disintegration when chewed or allowed to
dissolve in the mouth, have a creamy base.
8. Methods of preparations:
Commercially there are 3 methods of tablet preparation
Wet granulation method:
Dry granulation method
Direct compression method
WET GRANULATION METHOD:
Widely used process in pharmaceutical industry.
Process simply involves wet massing of powder
blend with granulating liquid, wet sizing and
drying.
9.
10. - Mixing drug and excipient.
- Preparation of binder solution.
- Mixing of binder solution with powder mixture to form
wet mass.
- Drying of moist granules.
- Mixing of screened granules with disintegrated glidants
and lubricant.
ADVANTAGES
Improves the flow of powder by increasing particle size and
density.
Increases and improves uniformity of powder density.
11. DISADVANTAGE
The greatest disadvantage of this process is its cost. It is
an expansive process because of labor, time, equipment,
energy and space requirement.
DRY GRANULATION METHOD:
In this process of tablet making, the powder mixture
is compressed without the use of heat and solvent,
Used for heat and moisture sensitive content.
12.
13. - Weighing and milling of formulation ingredients (Drug
substances and Excipient).
- Mixing of milled powders.
- Compression of mixed powders into slugs.
- Milling and sieving of slugs.
- Mixing with disintegrated and lubricant.
Compression into tablet
ADVANTAGE:
Dry granulation is a simple and low cost method.
15. DIRECT COMPRESSION:
Direct compression is a popular choice because it
provides the shortest, most effective and least complex
way to produce tablets.
It is least expensive.
- Tablets are being formed by compressing the granules
by using the compression machine.
- It is formed by pressing the powder granule in die with
lower and upper punch.
16.
17. -Tablets formation takes place by the combined pressing
action of two punches ( lower and upper) and a die.
- The material which are available in crystalline form, free
flowing and binding characteristics can be compressed
directly. But majority of the drugs can not be compressed
easily because they may disintegrate.
- The drugs which can be compressed directly are Nacl,
NaBr, KCl, KBr, KmnO4.
18. Properties and route of administration of tablets
dosage form:
•A tablet dosage form is mostly administered by oral route
and placed sublingually.
•A seldom route of administration could be buccal, rectal or
vaginal depending upon the purpose it is being used for.
•A tablet must be hard enough to bear the shocks which may
possible at the time of dispensing.
•It must be uniform in weight and in drug content.
19. ADVANTAGES:
•Tablets are available at low cost, convenient to patient and easy to swallow.
•Stable according to microbiological attributes.
•Provide prolonged stability to active ingredients
•Packing, production and storage is cheap. It does not require huge spacings.
•It is easy to divide tablet into halves and quarters when fractional dose is
recommended.
•It can be formulated as a special release product such as enteric or delayed
release.
20. DISADVANTAGES:
•Oxygen sensitive drugs require special coatings and hence it
increases the costs.
•Swallowing hard tablet is difficult for children and elderly patients.
•A liquid formulation is difficult to formulate into solid tablet.
•Some tablets have low bioavailability.
21. STORAGE AND PACKAGING:
Tablets are stored in tight containers, where there is low
humidity, and protected from extremes temperature.
Generally tablets are packaged with a desiccant packet.
They should be packed in light resistant containers.
23. REFERENCES:
•Ansels pharmaceutical dosage form and drug delivery systems
By LOYD V. ALLEN, Jr NICHOLAS G, POPPVICH HOWARD C. ANSEL, Lippincott
Williams and Walkins.
•Martins physical pharmacy and pharmaceutical sciences
•Images from websites ( pubscience, wikipedia, pharmaimages)