Hard-shelled capsules, which contain dry, powdered ingredients or miniature pellets made by e.g. processes of extrusion or spheronization. Both of these classes of capsules are made from aqueous solutions of gelling agents, such as animal protein or plant polysaccharides or their derivatives . Since their inception, capsules have been viewed by consumers as the most efficient method of taking medication.
Single-piece gel encapsulation
They used individual iron molds for their process, filling the capsules individually with a medicine dropper. Later on, methods were developed that used sets of plates with pockets to form the capsules. Although some companies still use this method,the equipment is no longer produced commercially. His innovation used a rotary die to produce the capsules.
They were then filled by blow molding. This method was high-yield, consistent, and reduced waste. Softgels can be an effective delivery system for oral drugs, especially poorly soluble drugs. This is because the fill can contain liquid ingredients that help increase solubility or permeability of the drug across the membranes in the body.
Two-piece, hard starch capsules
Reconstruction from µCT-data of a hard starch capsule containing Diclofenac. Flight through the image stack of the above scan. The capsules are made in two parts by dipping metal pins in the gelling agent solution. The capsules are supplied as closed units to the pharmaceutical manufacturer.
Before use, the two halves are separated, the capsule is filled with powder or more normally pellets made by the process of Extrusion & Spheronization and the other half of the capsule is pressed on. With the compressed slug method, weight varies less between capsules. However, the machinery required to manufacture them is more complex.
The process of encapsulation of hard gelatin capsules can be done on manual, semi-automatic and automatic machines.Softgels are filled at the same time as they are produced and sealed on the rotary die of a fully automatic machine.