Solid Pharmaceutical Dosage Forms -
Capsules
Learn about the capsule dosage forms-Types of capsules as
Hard Gelatin Capsules, Soft Gelatin Capsules, Modified Release Capsules and
Enteric Capsules.
Capsules are
solid pharmaceutical dosage forms in which the drug or a mixture of drugs is
enclosed in a Gelatin Shell or any other suitable material to form various
shapes. Capsules generally contain a single dose of active ingredients and are
taken orally. Excipients such as opaque fillers, antimicrobial preservatives,
sweetening agents, permitted flavoring agents and one or more coloring agents
may be added. Capsules may be printed on outer surface.
Capsules may contain
medications in solid, paste or liquid forms. The API filled in the capsules may
contain excipients as solvents or fillers but the shell should not be attacked
by the content thereby releasing the contents of the capsule.
The contents
of capsules other than Modified-release
(Sustained-release) do not contain any added coloring agent.
There are
following types capsules:
1.
Hard Gelatin Capsules
2.
Soft Gelatin Capsules
3.
Modified Release Capsules
4.
Enteric Capsules
1. Hard Gelatin Capsules:
Hard gelatin capsules
contain the active ingredients in the form solids. When two drugs of different
properties are added in a capsule, one of them should be in the form of tablet,
pellet or small capsule and then enclosed in large capsule.
Hard
gelatin capsules are manufactured by dipping capsule shell shaped pins into
liquid gelatin solutions, after that gelatin films on the pins are dried,
trimmed, and then removed from the pins. Body and cap pieces are supplied
unlocked.
2. Soft Gelatin Capsules:
Soft gelatin
capsules made from gelatin (sometimes called softgel) are somewhat thicker than
that of hard gelatin capsules and may be plasticized by adding the sorbitol or
glycerin. The ratio of plasticizer depends upon the environmental conditions as
well as the nature of the contents filled into the soft gelatin capsule.
Like hard
gelatin shells, the composition may include approved dyes and pigments and
preservatives. Flavors may be added and up to 5% sucrose may be included for
its sweetness and to produce a chewable shell. Soft gelatin capsule shell
generally contains 6% to 13% of water.
Soft gelatin
capsules are generally filled during their formation and sealed with machines.
Soft gelatin
capsules generally contain liquid or solid drugs dissolved in suitable liquids
to form paste. In some cases granules and powders may be filled into the soft
gelatin capsules.
3. Modified Release Capsules:
Modified-release
capsules are hard or soft gelatin capsules in which the contents or the shell,
or both are prepared by special process to modify the rate of release the
active ingredients of the capsule.
4. Enteric Capsules:
Enteric
Capsules are hard or soft gelatin capsules those are resist against the gastric
fluid but dissolves in the intestinal fluid to release its contents.
During manufacturing,
packaging, storage and distribution of capsules, their microbial quality should
be maintained as per their acceptance criteria because of the possibilities of microbial growth in gelatin.
