Raw materials of capsule shell

2. Raw materials of capsule shell
Similar raw materials have been used in the manufacture of both types of capsule.They contain mainly:
I. WATER
II. COLOURANTS
III. PRESERVATIVES
IV.GELATIN
V. OPACIFIERS
VI.PLASTICIZERS

3. WATER
The demineralized water content of gelatin solution
used to produce a soft gelatin capsule shell depends on
the viscosity of gelatin used (0.7-1.3 % of water to each
part of dry gelatin), 1: 1 ratio being typical.

4. COLOURANTS
Bascially used to identify a product in all stages of manufacturing and for patient attractiveness. The colourants that can be
used are of two types:
****water-soluble dyes
****insoluble pigments.
To make a range of colours; dyes and pigments are mixed together as solutions or suspensions.
Most dyes used currently are non-azo and the three most widely used are
Erythrosine (E127),
Indigo carmine (E132) and
Quinoline yellow (E104).

5. Two types of pigment are used:
****Black, red and yellow iron oxides (E172)
****Titanium dioxide (E171), which is white and is used to make the
capsule opaque

6. PRESERVATIVES
Preservatives and surfactants are added to the gelatin solution during capsule manufacture to aid in
processing .Gelation solution are an ideal medium for bacterial growth at temperatures below55℃ .
Preservatives are added to prevent microbes growth in the gelatin shell. Moisture content above
16%(w/v) in gelatin film is ideal for microbes growth. Common preservatives includes
***sulfur oxide
***sorbic acid
***methyl propyl esters of P-hydroxyl benzoic acid
***organic acid

7. Some hard gelatin containing not more than 0.15% (w/w) of sodium lauryl sulfate for use in hard
gelatin capsule manufacture. This functions as a wetting agent, to ensure that the lubricated metal
moulds are uniformly covered when dipped into the gelatin solution

8. GELATIN
Gelatin is heterogeneous(proteneous) product derived by hydrolytic
extraction of animal's collagen.
The sources of gelatins including animal bones, hide portions and
frozen pork skin.
It is a major component of capsule. It’s MW is (20-250) KDa.

9. TYPES
Type A
Derived from acid treated precursor that exhibits an iso electric point at pH-9. It is manufactured
mainly from animal bones
TYPE B
Derived from alkali treated precursor that exhibits an iso electric point at pH-4.7. It is manufactured
mainly from pork skin.

10. PROPERTIES
Gelatin possesses following properties that make it suitable for the manufacture of capsules:
1.It is non-toxic, widely used in foodstuffs, and is acceptable for use worldwide.
2. It is readily soluble in biological fluids at body temperature.
3. It is a good lm-forming material, producing a strong flexible film
4.Non-transmissible of disease.
5.Gelatin films are homogeneous in structure, which gives them their strength.
6.Gelatin has thixotropic properties including elasticity, plasticity in certain condition

11. 7. Solutions of high concentration, e.g. 40% (w/v), are mobile at 50 °C
8. Bloom strength (The Bloom strength is a measure of gel rigidity. It is determined by preparing a
standard gel (6.66% w/v) and maturing it at 10 °C. It is defined as the load in grams required to
push a standard plunger 4 mm into the gel.)
***Hard gelatin :200-250 gm
***Soft gelatin :150gm

12. PREPARATION

13. Gelatin is a substance of natural origin that does not occur as such in nature. It is prepared by the
hydrolysis of collagen, which is the main protein constituent of connective tissues

14. OPACIFIERS
• An opacifier is a substance added to a material in order to make the ensuing system opaque.An
example of a chemical opacifier is titanium dioxide.
• Titanium dioxide can either be used alone to produce a white opaque shell or in combination with
pigments to produce a colored opaque shell.

15. PLASTICIZERS
• Plasticizers are additives that decrease the plasticity or decrease the viscosity of a material.These
are substances which are added in order to alter their physical properties.The plasticizers are more
common for soft gelatin capsules.The ratio(w/w) of dry plasticizer to dry gelatin determines the
“hardness” of the gelatin shell assuming that there is no effect from the capsulated material.
• Example: glycerol,glycerine