Introduction
Tablets are
solid dosage forms usually prepared with the aid of suitable pharmaceutical
excipients.
They may
vary in size, shape, weight, hardness, thickness, disintegration and
dissolution characteristics and in other aspects, depending on their intended
use and method of manufacture. Most tablets are used in the oral administration
of drugs.
Definition:
“Tablets may be defined as solid unit dosage form of
medicament or medicaments with or without suitable diluents and prepared either
by molding or compression.”
Many of these are prepared with colorants and
coating of various types.
Other tablets, such as those administered
sublingually, buccally, or vaginally, are prepared to have the features most
applicable to their particular route of administration.
Tablets are prepared primarily by compression, with
a limited number prepared by molding.
Compressed tablets are manufactured with tablet
machines capable of exerting great pressure in compacting the powder or
granulated material. Their shapes and dimensions are determined by the use of
various shaped punches and dies.
Molded tablets are prepared on a large scale by
tablet machinery or on a small scale by manually forcing damped powder material
into a mold from which the formed tablets is then ejected and allowed to dry.
Some tablets are scored, or grooved, which allows
them to be easily broken into two or more parts. This enables the patient to swallow smaller portions
as may be desired, or when prescribed, it allows the tablet to be taken in
reduced or divided dosage.
Some tablets that are not scored are not intended to
be broken or cut by the patient since they may have special coatings and/or
drug release features that would be compromised by altering the tablet’s
physical integrity
Advantages:
They
are easy to carry.•
They
are easy to swallow.•
They
are attractive in appearance.•
Unpleasant taste can be masked by sugarcoating.•
They
do not require any measurement of dose. The strip or blister packing has
further facilitated the process by taking the dose by the patient. Moreover it
provides a sealed covering which protects the tablets from atmosphere
conditions like air, moisture and light.•
Some
of the tablets are divided into halves and quarters by drawing lines during
manufacturing to facilitate breakage whenever a fractional dose is required.•
An
accurate amount of medicament even if very small amount can be incorporated.•
Tablets provide prolonged stability to medicaments.•
The
incompatibilities of medicaments and their deterioration due to environmental
factors are less in tablet forms.•
Since they are generally produced on a large scale
therefore cost of production is relatively low, hence economical.
Disadvantages:
Children and elder•ly patients cannot swallow the tablets.
Packaging also involves quite a lot of expenditure.•
Essential Qualities of a Good Tablet:•
They
should be accurate and uniform in weight.•
The
drugs should be uniformly distributed throughout tablets.•
The
size and shape should be reasonable for easy administration.•
The
tablets should not be too hard that it may not disintegrate in the stomach.•
There
should not be any incompatibilities.•
They
should be chemically and physically stable during storage.•
They
should not break during transportation or crumble in the hands of patients.•
They
should be attractive in appearance.•
There
should not any manufacturing defects like cracking, chipping or discoloration.•
After
administration it should disintegrate readily.•
They
should be easy and economical in production.•
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