- The gelatin used in the manufacture of capsules is obtained from collagenous material by hydrolysis.
- Blends are used to obtain gelatin solutions with the viscosity and bloom strength characteristics desirable for capsule manufacture.
- There are two types of gelatin, Type A, derived mainly from pork skins by acid processing, and Type B, obtained from bones and animal skins by alkaline processing.
- Blends of both type gelatin are used to obtain gelatin solutions with the viscosity and bloom strength characteristics desirable for capsule manufacturing of Hard Soft gelatin Capsules.
Types of Gelatin
Gelatin is a purified protein obtained by partial hydrolysis of animal collagen.
| Type A Gelatin (195 Bloom) | Type B Gelatin (150 Bloom) |
| Extracted by acidic hydrolysis of bovine bone, bovine hide and pork skin | Extracted by alkaline hydrolysis of bovine bones and hide |
| High gel strength and can resist cross- linking better than type B | High plasticity and elasticity (compared to acid pork skin) |
| pH ~ 3.8-6.0 | pH ~ 5.0-7.4 |
| Isoelectric point ~ 6-8 | Isoelectric point ~ 4.7-5.3 |
Properties of Gelatin
-A protein in nature so Protein is digested by proteolytic enzyme hence Gelatin is therapeutically inert.
-Insoluble in cold water
-Soluble in hot water
-Protein is digested by a proteolytic enzyme
-Obtained from the hydrolysis of collagen from animal connective tissue, bone, skin
-Chemical & physical properties of Gelatin depend upon the source of collagen & the manner of extraction.
Jelly Strength of Gelatin IP
The jelly strength of Gelatin is the weight, in g, necessary to give a 4-mm depression in a jelly containing 6.67 per cent w/w, matured at 10° C, using a plunger 12.7 mm in diameter.
Apparatus to measure Gel Strength- Gelometer
A gelometer consisting of a cylindrical piston 12.6 to 12.8 mm in diameter with a plane pressure surface with a rounded edge 0.5 mm in radius attached to a device whereby the load exerted by the piston can be increased at a constant rate of 40 g per second and the vertical movement of the piston can be stopped within 0.025 seconds when it has descended 3.9 to 4.1 mm.
Microbial contamination test for Gelatin
- Total microbial count, not more than 1000 per g;
- 1 g is free from Escherichia coli;
- 10 gm is free from Salmonellae.
Gelatin intended for use in the preparation of pessaries and suppositories complies with Jelly strength between 150 and 250 g.