ST. JAMES COLLEGE OF
DESIGN & FORMULATION OF CAPSULES 1
The term capsule is derived from
the Latin word capsula, meaning a
The first capsule prepared from gelatin was a one-
piece capsule patented in France by Mothes and Du
Blanc in 1834.
Capsules are solid dosage forms in which the drug
substance is enclosed within either a hard or soft
soluble shell, usually formed from gelatin.
DESIGN & FORMULATION OF CAPSULES 2
Today capsules may be classified as either hard or
soft, depending on the nature of the shell. Most
capsules of both types are intended to be swallowed
whole; however, some soft gelatin capsules are
intended for rectal or vaginal insertion as
TYPES OF CAPSULES
1) Hard gelatin capsules
2) Soft gelatin capsules
DESIGN & FORMULATION OF CAPSULES 3
Tasteless, odorless and can easily be administered.
Combination of powders we can use
These are attractive in appearance.
The drugs having un-pleasant odor and taste are enclosed in
a tasteless shell.
They can be filled quickly and conveniently.
Physician can change the dose and combination of drug
according to patient requirement.
They are economical.
They are easy to handle and carry.
DESIGN & FORMULATION OF CAPSULES 5
Hygroscopic drugs are not suitable for filling into
capsules, because they absorb water present in capsule
shell makes shell very brittle and ultimately lead to
crumble into pieces.
The concentrated solutions which require previous
dilution are unsuitable for capsules because if
administered as such lead to irritation into stomach.
DESIGN & FORMULATION OF CAPSULES 6
HARD GELATIN CAPSULE
The hard gelatin capsule consists of two pieces in the
form of cylinders closed at one end. The shorter piece is
called the cap. This cap fits over the open end of longer
piece called body.
Hard gelatin capsules are also known as dry-filled
capsules or two piece capsules. Hard gelatin capsules
consists of two parts known as capsule body (longer
part) and the capsule cap(the shorter part) The drug
substance is placed in the body and the caps are slided
over it, hence enclosing the drug substance.
DESIGN & FORMULATION OF CAPSULES 7
For human use,empty capsules ranging in size from
000(the largest)to 5 (the smallest)are commercially
DESIGN & FORMULATION OF CAPSULES 8
•HGC typically are filled with powders, granules &
•Contain body & cap.
•They are cylindrical in shape.
•Less amount of plasticizers.
DESIGN & FORMULATION OF CAPSULES 9
FORMULATION OF HARD GELATIN SHELL :
GELATIN: It is prepared by the hydrolysis of
collagen obtained from animal connective tissue,
bone and pork skin.
There are two types of gelatin
Type A (Acid hydrolysis of pork skin)
TypeB (Alkaline hydrolysis of bones)
The two types of gelatin can be distinguished by iso
electric point as:
Type A iso electric point near to PH 9
Type B iso electric point near to PH 4.7
DESIGN & FORMULATION OF CAPSULES 10
The physiochemical properties of gelatin of most
interested to the shell manufactures are-
1) Bloom strength
It is measured in a bloom gelometer which determine the
weight in grams required to depress a standard plunger a
fixed distance in to the surface of a 6.66 % w/v gel under
Bloom strength in the range of 150-280 is considered
suitable for capsule.
DESIGN & FORMULATION OF CAPSULES 11
The viscosity of the gelatin is vital to control the
thickness of the cast film.
Viscosity is measured on a standard 6-2/3%w/w
solution at 600 C in a capillary pipette & generally in the
range of 30-60 milli poise.
Sorbitol & glycerol is used.
DESIGN & FORMULATION OF CAPSULES 12
Colour approved by D & C act.
Soluble synthetic dye(coaltar dyes) & insoluble dyes(iron
Colorant plays an important role in improving patient
Thus the color of drug product may be selected in
consideration of the disease state for which it is intended.
e.g. White – analgesics.
Orange/Yellow – stimulants & anti depressants
It provide protection against light or or conceal the contents.
DESIGN & FORMULATION OF CAPSULES 13
Demineralised water is used.
Finished capsule contain an equilibrium moisture
content of 12-16%.
Propyl and Methyl Parabens.
If needed flavouring agent may be added to the
Eg. Ethyl vanillin, essential oil.
DESIGN & FORMULATION OF CAPSULES 14
GELATIN CAPSULE FORMULATION
The formulation of hard gelatin capsule includes different
substances which promote the release of drug
constituent from the hard gelatin capsule these include:-
DESIGN & FORMULATION OF CAPSULES 15
1) ACTIVE INGREDIENTS :-
The amount and type of active ingredients influence
capsule size and the nature and amount to be used in the
Active ingredients tends to make up to the high
percentage of the contents of a capsule as compared to
Smaller the size of active ingredients, larger will be the
surface area of the active ingredients, hence greater will be
the rate of dissolution of the active ingredients.
DESIGN & FORMULATION OF CAPSULES 16
Granulation of the active ingredient in the case of hard
gelatin capsule is carried out to
Increase the flow properties.
Increase Drug dissolution.
Fillers are used to increase the bulk of the
The most common capsule diluents are starch,
lactose & dicalcium phosphate.
These substances improve flow properties and
DESIGN & FORMULATION OF CAPSULES 17
Glidants are used to improve the fluidity of powders.
Glidants include the colloidal silica, corn starch, talc
and magnesium stearate.
They are fine particles that appear to coat the surface
of the bulk powder and enhance fluidity by reducing
roughness by filling surface irregularities reducing attractive
force by ….
Physically separating the host particles.
Modifying electrostatic charges.
Acting as moisture scavengers.
DESIGN & FORMULATION OF CAPSULES 18
Optimum concentration for flow is less then 1% & typically
lies between 0.25-0.50 percent. Exceeding this
concentration will result in no further improvement in flow.
Capsule formulation usually requires lubricants :
To ease the ejection of plugs.
To reduce filming on piston and adhesion of powders to metal
Reduce the friction between sticking surfaces in contact
Ex:- magnesium stearate and stearic acid.
DESIGN & FORMULATION OF CAPSULES 19
In capsule formulation, the substances which have
superior swelling or moisture absorbing properties are
generally used as disintegrants. Such disintegrants are
called “super disintegrants”.
E.g. croscarmellose sodium, sodium starch glycolate
Surfactants are used in capsule formulation to increase
the wetting of the powder mass and enhance drug
DESIGN & FORMULATION OF CAPSULES 20
Commonly used surfactants are sodium lauryl sulphate
and sodium docusate.
Surfactant in concentration range of 0.1-0.5% is usually
7) HYDROPHILIC AGENTS:-
Hydrophilic agents are used to improve the
wettability of poorly soluble drug present in hard gelatin
E.g.:- Both wettability of the drug and the rate of
dissolution of hexobarbital from hard gelatin capsule could
be enhanced if the drug is treated with methyl cellulose or
hydroxyl ethyl cellulose.(hydrophilic agents).
DESIGN & FORMULATION OF CAPSULES 21
SOFT GELATIN CAPSULES
Made from a more flexible plasticized
gelatin film than hard gelatin capsules.
Most capsules of either type is intended
to be swallowed whole.
Some soft gelatin capsules are intended for rectal or
vaginal insertion as suppositories.
Most capsules product manufactured today are of the
hard gelatin type.
On the basis of shape, content & other features intended
to make the taste of certain unpleasant tasting medication,
they quickly gained popularity.
DESIGN & FORMULATION OF CAPSULES 22
•SGC are filled with solution or suspension of drug in
liquids that will not solubilize the gelatin shell.
• Consist of single unit after sealing.
•Available in ROOT shapes i.e. round,oval,oblong & tubular
• Plasticizers & preservatives are more.
•Most accurate & precise of all solid oral dosage form.
• More flexible plasticized gelatin film.
DESIGN & FORMULATION OF CAPSULES 23
DESIGN & FORMULATION OF CAPSULES 24
SHAPES OF SOFT GELATIN CAPSULES
Composition of the shell
The basic component of soft gelatin shell is gelatin;
however, the shell has been plasticize
The ratio of dry plasticizer to dry gelatin determines the
“hardness” of the shell and vary from 0.3-1.0 for very
hard shell to 1.0-1.8 for very soft shell
Up to 5% sugar may be included to give a “chewable”
quality to the shell
The residual shell moisture content of finished capsules
will be in the range of 6-10%.
DESIGN & FORMULATION OF CAPSULES 25
II. Formulation :
Formulation for soft gelatin capsules involve liquid.
Materials generally formulated to produce the smallest
possible capsule consistent with maximum stability,
therapeutic effectiveness and manufacture efficiency.
The liquids are limited to those do not have adverse effect
on gelatin walls.
Emulsion can not be filled because water will be released
that will affect the shell.
The pH of the liquid can be between 2.5 and 7.5.
DESIGN & FORMULATION OF CAPSULES 26
Liquids or a combination of a miscible liquid, a
solution of solid in liquid or a suspension of solid in
DESIGN & FORMULATION OF CAPSULES 27
VEHICLES USED IN SOFT GELATIN CAPSULES
Two main groups :
1. Water - immiscible, volatile & non volatile liquids
as: Vegetable , aromatic oils & mineral oil, Aromatic
& aliphatic hydrocarbons,
Acetylated glycerin, esters, and organic acids.
2. Water - miscible, nonvolatile liquids as:
Polyethylene glycols (PEG) with low molecular weight
used more recently because of their ability to mix with
water and accelerate dissolution of dissolved or
suspended drugs, Nonionic surface active
agents(Polysorbate 80) & Propylene glycol
DESIGN & FORMULATION OF CAPSULES 28
HARD GELATIN CAPSULE SOFT GELATIN CAPSULE
1)Two pieces (large body & short
2) Cylindrical shape.
3) Powder drug or pellets coated
with drug are encapsulated.
4) Gelatin in Hard form is used.
5) Capsules sealed after filled to
ensure that medicaments not
come out of capsule due to
6) 8 different type of sizes are
1) One piece & hermetically
2) Available in round , oval & tube
3) Liquid & Semi liquid fill &
unstable substances are
4) Molten gelatin are used.
5) Filling & sealing of soft gelatin
capsules are done in a
combined operation on
6) No specific sizes are available
DESIGN & FORMULATION OF CAPSULES 29
The design and manufacture of medicines
Fourth edition,by Michael.E.Aulton &Kevin
2)The theory and practice of industrial pharmacy
By Leon Lachman , Herbert .A .Libermann ,
Joseph.L.Kanig, Third edition
Published by Varghese publishing house
DESIGN & FORMULATION OF CAPSULES 30
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FORMULATION TECHNOLOGY:DESIGN & FORMULATION OF CAPSULES