Future Possibilities for Capsules
Consumer interest in “natural” products has increased
in recent years, not only in the U.S. but also in many regions
of the world where culture and religion play an important role
in consumer choices. In these communities, there is often a strong
preference for plant-derived materials. As a result, there is a
growing global demand by consumers for natural-origin capsules.
For this reason, Qualicaps has maintained its R&D
focus on the development of new capsule materials for the future
and specifically on non-animal alternatives.
The following is a brief explanation of some of the current development
work on new film materials for hard two-piece capsule delivery
systems.
(1) Natural Materials
Pullulan -
Pullulan is a water-soluble polysaccharide
derived by bacterial fermentation from corn. It is used currently
in the production of foods, pharmaceuticals and cosmetics. The
film formation properties of Pullulan are similar to gelatin and
dried capsules are comparatively weak in physical strength. Like
gelatin, Pullulan requires water to act as a film plasticiser,
which may have a negative effect on active ingredients. In addition,
there is presently only one supplier of the raw material, which
makes it unsuitable for multi-national use. There is no price advantage
in using it and it does not show any meaningful advantages over
hypromellose. For these reasons Qualicaps has chosen to
prioritize the development of Hypromellose capsules over Pullulan.
(2) Semi-synthetic Materials
Starch derivatives –
Starches occur naturally in many plants
and have always been an integral part of the human diet. One of
the more commonly used refined starches comes from potatoes. Starches
can be modified physically or chemically to improve their film
forming characteristics and to impart other desirable properties
for the manufacture of hard two-piece capsules. These do not have
the same shape as standard capsules, need different change parts
on filling machines and give problems with powder fills. In addition,
the aqueous solubility of starch-based capsules is slower than
gelatin capsules.
(3) Synthetic materials
Significant research is underway at our
Corporate Research Laboratories examining the application of
unique synthetic food grade polymers for the manufacture of hard
two-piece capsules to act as a special delivery system. To date
several materials have been identified as possessing excellent
film forming properties. Prototype capsules have been manufactured
from a pharmaceutical polymer. Early results indicate that these
capsules possess excellent delivery properties. Capsule shells
can be manufactured with properties to provide targeted delivery,
which are based primarily on pH changes in the G.I. tract.
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