Capsule is a also one of pharmaceutical dosage form.

1. .
Capsules
Capsules are solid dosage form in which one or more medicaments are enclosed in a water
soluble, biodegradable shell made up of gelatin.
Advantages of capsules for oral Administration:
• Easy to swallow due to their smooth and slippery nature.
• Easy to handle and carry.
• Can mask the unpleasant taste, colour and odour of drug using tasteless shell.
• Better bioavailability than tablets and faster onset of action than tablets.
• The shells are therapeutically (due to made from gelatin) inert and easily and quickly digested
in gastrointestinal tract.
• The shells can be opacified (with titanium dioxide) or coloured, to give protection from light.
• They are economical.
• The capsule releases the medicament as and when desired in GIT.

2. Types of Capsules:
 Hard Gelatin Capsules
 Soft Gelatin Capsules
1. Hard Gelatin Capsules:
 These are used for administration of solid medicaments. It consists of two parts i.e. body and
cap.
 The powdered material is filled into the cylindrical body of the capsule and then the cap is
placed over it.
Cap
Body

3. Capsules number and its approximate capacity:
Capsules number approximate capacity in mg
000 950
00 650
0 450
1 300
2 250
3 200
4 150
5 100

4. Excipients used in the filling of capsules:
 Diluents: The commonly used diluents are lactose, mannitol, sorbitol, starch etc.
 Absorbents: Oxides and carbonates of magnesium and calcium are added to the powdered
drugs. These inert materials act as a protective sorbent.
 Glidants: Talc, magnesium stearate and calcium stearate.
 Antidusting compounds: Inert edible oils are added to the formulation to avoids dust
comes out of the automatic filling machine at the time of filling of capsules.

5. Methods of filling the hard gelatin capsules:
 The capsules can be filled either by hand or by a semi-automatic machine or by an automatic
filling (ex. Zanasi automatic capsule filling machine, Hofliger Karg automatic capsule filling
machine etc.) machine.

6. Capsule filling machine (Hand operated):
A hand operated gelatin capsule filling machine
consists of the following parts:
• A bed with 200-300 holes.
• A capsule loading tray.
• A powder filling tray.
• A pin plate having 200 or 300 pins
corresponding to the number of holes in the bed
and cap holding tray.
• A lever handle.
• A Cam handle.
• A plate fitted with rubber top.

7. 2. Soft Gelatin Capsules:
 These are used for the administration of liquid medicaments (oils, suspension, food
concentrates and ophthalmic products).
 These types of capsules are available in round, oval and tube like shapes.
 The gelatin is plasticized by the addition of glycerin and sorbitol etc. The soft gelatin shell
may contain a preservative to prevent the growth of fungi.
 All liquids used for filling must flow by gravity at a temperature of 350C or less.
 The sealing temperature of gelatin films is 37-400⁰C.

8. .
 Methods of filling of soft gelatin capsules: Soft gelatin capsules are generally filled
mechanically. The manufacturing of the capsule shell and the filling of medicament take
place simultaneously.
 Manufacturing of Soft gelatin capsules: Soft gelatin capsules manufactured by four
methods:
 Plate process
 Rotary die process
 Reciprocating die
 Accogel machine

9. Rotary die machine:
 Rotary die machine consist of two hoppers and two rotating dies, liquids gelatin
mixture is placed in one hopper and the liquid medicament in the other hopper.
 The two rotating dies rotate in opposite directions when the fluid gelatin mixture
enters the machine from the hopper it produces two continuous ribbons.
 Half shell of the capsule is formed.
 At this stage the measured quantity of the medicament is filled in to it with the
stroke of a pump with the subsequent movement of the dies the
other half capsule is formed.
 The two halves of the capsules are sealed together by the heat &
pressure of the rotating dies.
 As the die rolls rotate, the convergence of the matching.
 die pockets seals and cuts out the filled capsules.

10. Special application of capsules:
 Enteric coated capsules: These capsules do not disintegrate in the stomach (acidic
medium) but break up in the intestine (alkaline medium). Ex. Rabeprazole Sodium enteric
coated capsule.
 Sustained release capsules (SR capsules): In order to maintain proper blood
concentration of the medicament and reducing the number of doses per day, a capsule,
containing numerous coated pellets, is administrated that release the drugs successively
ovar a long period. Ex. Domperidone SR Capsule.
 Rectal capsules: Soft gelatin capsules also used for rectal and vaginal suppositories. Ex.
Dulcolax Capsule.

11. Evaluation of capsules:
 Weight variation test:
 In which 20 capsules are individually weighed and standard deviation from mean weight was
measured that should not be <90% or >110%.
 Content uniformity test:
 The amount of active ingredient should be within the range of 85% to 115% of the label amount for 9
of 10 capsules, with no unit outside the range of 70% to 125% of label amount.
 Disintegration test for capsules:
 The capsules are placed in the basket-rack assembly, which is repeatedly immersed 30 times per
minute into a thermostatically controlled fluid at 370⁰C and observed over the time described in the
individual monograph.
 Dissolution test for capsules:
 The apparatus, dissolution media and test is the same as that for uncoated and plain coated tablets.

12. .
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