Iron Oxide Coloring For Gelatin Based Drug Capsules

A major supplier of gelatin capsules for the pharmaceutical industry that has successfully designed, developed and manufactured a range of innovative solutions to help their customers improve 'swallowability' of capsules and provide visually appealing dosage forms had a new challenge. With a new process to incorporate various iron oxides as coloring agents they were having trouble with particles forming clusters resulting in poor yield and uneven coloring.

As part of the new process they the incorporation of various iron oxides as coloring agents was introduced to create reds, yellows and purples. Although iron oxides are generally supplied in pre-micronised form, the particles tend to reagglomerate and form hard lumps which conventional agitation cannot disperse. This leads to poor yield and an uneven color dispersion or flecks in the finished capsule. A high shear mixer was needed to reduce the particles back down to their finest constituent parts.