An alternative to mammalian gelatin for use in pharmaceutical soft capsules has been discovered by researchers at the School of Pharmacy and Chemistry at Liverpool John Moores University.
The new capsule, made from fish gelatin, will put an end to fears of the spread of viral infections through mammalian gelatin, including BSE and variant CJD. Fish gelatin will also be acceptable to people who do not consume mammalian products.
There are currently two types of capsules: two-piece hard gelatin capsules (used for powders) and one-piece soft gelatin capsules (used for liquids). Starch is now widely used for hard capsules, but soft capsules pose more of a problem. No-one has yet developed an alternative material for soft capsule prescription medicines although several companies have been working on this issue for the past few years. These capsules need to be robust enough for high-speed filling machinery while also having elasticity for filling and softening characteristics that allow the capsule to seal rapidly after filling.
Dr Mark Dyas, senior lecturer in pharmaceutical sciences at Liverpool John Moores University, says that the results of studies carried out by his team, indicate that fish gelatin might prove to be a useful replacement for mammalian products. However, Dr Dyas added that, using fish gelatin, while avoiding mammalian source material, will not be acceptable to all people. “This is only a stepping stone. Ultimately we need to get away from animal-derived products altogether,” he explained.
The researchers are now looking at plant-derived materials and they have identified a fruit biopolymer that looks promising as a source for capsule shells.
“This type of material – which might not previously have been thought of for use in pharmaceuticals – gets rid of fears over disease transmission and is also suitable for those who don’t like taking animal-based material,” Dr Dyas commented. “It brings the pharmaceutical world into the 21st Century,”
Gelatin is a biopolymer. Traditionally, bovine and porcine gelatins have been used for capsule shells.
Investigation of the thermomechanical properties of fish gelatin when mixed with glycerol and water – the standard mixture used for soft capsules – showed it to have similar behaviour to bovine and porcine gelatin.
The Royal Pharmaceutical Society of Great Britain (RPSGB) is the regulatory and professional body for pharmacists in England, Scotland and Wales. The primary objective of the RPSGB is to lead, regulate and develop the pharmacy profession.