Film forming compositions comprising modified starches and iota-carrageenan and methods for manufacturing soft capsules using same

Abstract

Disclosed herein are compositions comprising a modified starch and a carrageenan, especially iota-carrageenan, where the compositions are suitable for use in manufacturing soft capsules.

Description

RELATED APPLICATIONS[0001]This application is a continuation-in-part application and is based on U.S. Provisional Application Ser. No. 60 / 142,704; filed Jul. 7, 1999.FIELD OF THE INVENTION[0002]This invention relates to capsules and, more specifically, to soft capsules typically made using a rotary die apparatus. More specifically, it relates to novel compositions that are capable of forming films from which soft capsule shells can be made.BACKGROUND OF THE INVENTION[0003]Encapsulation within a soft capsule of a solution or dispersion of a nutritional or pharmaceutical agent in a liquid carrier offers many advantages over other dosage forms such as compressed, coated or uncoated solid tablets or bulk liquid preparations. Encapsulation of a solution or dispersion permits accurate delivery of a unit dose, an advantage which becomes especially important when relatively small amounts of the active ingredient must be delivered, as in the case of certain hormones. Such uniformity is more ...

AI Technical Summary

Benefits of technology

[0040]An additional unexpected property of the films according to the invention is that sealing occurs at substantially lower pressures than those experienced with mammalian gelatin based compositions. For example, conventional mammalian gelatin based films seal at pressures of about 1,724 kPa (250 psi) whereas the new films according to the present invention seal at about 207 kPa, more preferably about 552 kPa (30-80 psi). This saves energy and reduces the wear experienced by the rotary die. Also, the inventive film, when dry, (the film contains about 6 to 12% by weight water) is durable and impermeable to hydrophobic liquids.

[0043]In another embodiment, the invention provides films comprising water and a solids system. In the films of the present invention, the solid system comprises modified starch and iota-carrageenan. The films of the invention are capable of maintaining their form without being applied to a support; they do not lose their shape through splitting, lengthening, disintegration or otherwise by breakdown of the film when unsupported. However, the films may be stretched when pulled or compressed to a certain extent when an appropriate external force is applied.

[0058]The gelling carrageenan types (kappa and iota) are biosynthesized by the living seaweed as a non-gelling precursor, which is then turned into the gelling form by the action of the enzyme, dekinkase, which catalyzes the formation of the 3,6-anhydroglacatose ring. As mentioned previously, iota-carrageenan is only produced from Euchema Spinosum and produces the strongest gels with calcium ions (Ca++). The gels are very elastic and completely syneresis free at the normal concentrations for food application (i.e., 0.5 to 2% by weight). Although iota-carrageenan does not gel with Na+, diluted iota-carrageenan solutions will form thixotropic solutions also with Na+ as it acts as a stabilizing agent. In the best mode of the present invention, the Ca++ content is kept to a minimum.

[0059]In iota-carrageenan, the 1,3- and 1,4-linked units are respectively D-galactose-4-sulfate and 3,6-anhydro-D-galactose-2-sulfate. However, some of the 3,6-anhydro-D-galactose-2-sulfate rings may be replaced by D-galactose-6-sulfate, which may reduce considerably the gelling power of the iota-carrageenan.

[0072]ii) finished capsules exhibit greater stability when exposed to elevated humidity and temperature than capsules made using gelatin.

Problems solved by technology

The bound water, from about 6 to 12% by weight of the dry film, is not easily removable using conventional drying techniques and is not considered when describing the components of the dried film as a percentage of the composition.