1. Gelatin Preparation
2. Material (Fill) Preparation
Raw granular gelatin is mixed with glycerine and water. Coloring agent can also be added at this stage. Glycerine acts as a plasticizer in the gelatine compound. Other plasticizers can also be used either alone or in combination with glycerine, such as sorbitol. The proportions of each ingredient involved in the mixture should be considered carefully because the shell material needs to be adapted to formulation and/or environmental requirements. For instance the gelatin recipe may need to be adjusted to account for acidity, water content of the fill material or high humidity environmental conditions.
Gelatin Melting Tank
After the ingredients are combined, the mixture is placed into a reactor called as gelatin melter. The reactor surrounded by a thermal jacket heats the mixture while a very high torque tribune mixer stirs it under vacuum. At this stage, approximately 20% of gelatin mixture consists of water.
This process takes around 3 hours until the gelatin turns into a molten liquid mass. As soon as the liquid gelatin mass is ready for encapsulation process, it is transferred to ground heated tanks which are wheeled into the clean room where the main encapsulation machine is. It is really important to keep the liquid gelatin warm before or during the encapsulation process. Because the only way to keep the gelatin mixture as liquid is to keep it warm otherwise it will solidify like jelly. It is really important to plan and schedule the gelatin production in terms of time and quantity. At least, it requires 2 shift operational time.
Read More : Soft Gelatin Capsule Shell : Composition, Formula and Preparation
Material (Fill) Preparation
A homogeneous fill material plays a vital role to ensure the uniformity of each Softgel dose. Various equipment should be available, such as processing tanks, high-shear mixer, homogenizer and variety of mills is use.
There are two types of fill materials: oil mixtures or pastes.
Oil mixtures are very easy to formulate. The oils are mixed, deposited into a ground material tank and moved into the hopper of the encapsulation machine (i.e., vitamin E, fish oils).
Pastes are oils or polyethylene glycols added with powders. Two important factors that affect the homogeneity and flow of the paste should be considered:
1. particular size of powder. In order to allow homogeneous mixture, powder particles must not be thicker than 80 mesh.
2. viscosity of the mixture. If the mixture is not thin enough, it will not flow correctly through the machine injections.
Natural or artificial flavours, sweeteners and fragrances are commonly used to make chewable softgels or to mask the unpleasant taste and odor of the fill material such as fish oils. These can go into fill or gelatin material.
Read more : Basic Formulations of Soft Gelatin Capsule Preparation
Encapsulation is the manufacturing process that brings the gelatin shell and the fill material together to form Softgel capsules. It takes place in a closed environment called clean room where the relative humidity is around 20%. The gelatin shell and fill material are brought together simultaneously in the encapsulation machine.
Simultaneously, a sensitive and high accuracy positive displacement pump delivers the fill material into a heated wedge which sits between rotary dies. This wedge injects the fill material into the die cavities between ribbons just right before the die rolls cut the ribbons and seal the two halves together. The cool, dry air congeals the gelatin as the drum rotates so that a tacky, elastic band rolls off of the other end. This thin band is then automatically formed into capsules; filled with medicine, vitamins or other products; sealed; and dropped into a tray.
If the air blowing against the drum has too low a temperature, the gelatin will set too rapidly and become brittle which can cause the manufacturing process to grind to a halt. Too high of an air velocity will disturb the consistent thickness of the gelatin ribbon being formed. If the air temperature and humidity are too high, or the air velocity is too low, the gelatin will not solidify into a ribbon.
Thus, the need for constant control of the air being introduced to the drum is critical in the process. From the capsulating machines, the soft, moist capsules are transferred to drying drums or chambers for rapid drying. The extent of moisture to be removed during drying depends upon the size of the capsule, the number of capsules, and the period of time over which this moisture can be removed.
To be Continued : MANUFACTURING PROCESS OF SOFT GELATIN CAPSULE (Part II)