The manufacturing of empty hard gelatin capsule shells is a specialized process often done on an industrial scale by capsule suppliers.
Raw Materials:
Gelatin: Derived from animal collagen (commonly bovine or porcine sources), gelatin provides the structural matrix.
Plasticizers: Substances like glycerin or sorbitol are added to enhance flexibility and prevent brittleness.
Water: Acts as a solvent and plasticizer.
Manufacturing Process:
The manufacturing process of empty hard gelatin capsule shells involves the following steps:
Preparation of Gelatin Solution
Gelatin Source: Derived from partial hydrolysis of collagen (Type A: acid treatment; Type B: alkali treatment).
Ingredients: Gelatin (20–30% w/w), water (60–80% w/w), and optional additives (plasticizers, colorants, opacifiers).
Control: Temperature (50–60 °C) and viscosity are maintained for uniform wall thickness.
Dipping
Pins/Molds: Stainless steel pins (different diameters for body and cap) are dipped into the gelatin solution.
Depth & Time: Dipping depth and residence time control shell thickness.
Rotation and Drying
Rotation: Pins are rotated to evenly distribute the gelatin film.
Drying: Pins pass through drying tunnels (20–25 °C, 40–50% RH) to remove excess moisture.
Stripping & Trimming
Dried shells are stripped off the pins and cut to the desired length for body and cap sections.
Joining & Sorting
Body and cap are loosely joined to form a two-piece capsule, and defective shells are removed.