GELATIN CAPSULES

GELATIN CAPSULES

There are two basic types of gelatin:

    Type – A and Type – B.

The two types can be differentiated by their isoelectric points (7.0 – 9.0 for type A and 4.8 – 5.0 for type B) and by their viscosity and film forming characteristics.

Shell manufacture :

I.Dipping :

The pins are at ambient temperature; whereas the dipping solution is maintained at a temperature of about@@@ 50C in a heated, jacketed dipping pan.

The length of time to cast the film has been reported to be about@@@ 12 sec.

III.Drying :

The racks of gelatin coated pins then pass into a series of four drying oven.

Drying is mainly done by @@@@@@DEHUMIDIFICATION.

Storage :

Finished capsules normally contain an equilibrium moisture content of @@@@@13-16%.

To maintain a relative humidity of @@@@@40-60% when handling and storing capsules.

Filling of hard gelatin capsules:

Equipment used in capsule filling operations involves one often of two types of filling systems.

Zanasi or Martelli encapsulator:

Forms slugs in a dosatar  which is a hollow tube with a plunger to eject capsule plug.

Hofliger-Karg machine:

Formation of compacts in a die plate using tamping pins to form a compact.

Manufacture of Soft Gelatin Capsules:

I.Composition of the shell:

Similar to hard gelatin shells, the basic component of soft gelatin shell is gelatin; however, the shell has been plasticized.

The ratio of dry plasticizer to dry gelatin determines the “hardness” of the shell and can 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%.

II.Formulation :

Formulation for soft gelatin capsules involves liquid, rather than powder technology.

Materials are generally formulated to produce the smallest possible capsule consistent with maximum stability, therapeutic effectiveness and manufacture efficiency.

The liquids are limited to those that do not have an adverse effect on gelatin walls.

The pH of the @@@@@lipid can be between 2.5 and 7.5.

Emulsion can not be filled because water will be released that will affect the shell.

The types of vehicles used in soft gelatin capsules fall in to two main groups:

1.Water immiscible, volatile or more likely more volatile liquids such as vegetable oils, mineral oils, medium-chain triglycerides and acetylated glycerides.

2.Water miscible, nonvolatile liquids such as low molecular weight  PEG have come in to use more recently because of their ability to mix with water readily and accelerate dissolution of dissolved or suspended drugs.

All liquids used for filling  must flow by gravity at a temperature of 35c or less.

The sealing temperature of gelatin films is 37-40C.