Drug Administration part II

Solid dosage forms include tablets,
coated tablets, and capsules (B).

Tablets have a disk-like shape, produced
by mechanical compression of
active substance, filler (e.g., lactose, calcium
sulfate), binder, and auxiliary material
(excipients). The filler provides
bulk enough to make the tablet easy to
handle and swallow. It is important to
consider that the individual dose of
many drugs lies in the range of a few
milligrams or less. In order to convey
the idea of a 10-mg weight, two squares
are marked below, the paper mass of
each weighing 10 mg. Disintegration of
the tablet can be hastened by the use of
dried starch, which swells on contact
with water, or of NaHCO3, which releases
CO2 gas on contact with gastric acid.
Auxiliary materials are important with
regard to tablet production, shelf life,
palatability, and identifiability (color).

Effervescent tablets (compressed
effervescent powders) do not represent
a solid dosage form, because they are
dissolved in water immediately prior to
ingestion and are, thus, actually, liquid
preparations.


The coated tablet contains a drug within
a core that is covered by a shell, e.g., a
wax coating, that serves to: (1) protect
perishable drugs from decomposing; (2)
mask a disagreeable taste or odor; (3)
facilitate passage on swallowing; or (4)
permit color coding.

Capsules usually consist of an oblong
casing — generally made of gelatin
— that contains the drug in powder or
granulated form