(685b) Carrageenan/Starch (SeaGel®) Films As Gelatin Alternative for Soft-Shell Capsule Applications

Soft shell capsules continuously serve as a preferred oral drug/nutrition dosage form. Soft gelatin capsules have numerous shortcomings especially with the growing concerns about bovine spongiform encephalopathy (BSE or mad cow disease). Blends of carrageenan and starch were developed by DuPont Nutrition and Health (commercialized as SeaGel®) to replace gelatin in softshell capsule manufacturing. In this study, solution-cast films were used to predict performance in soft-shell capsule applications. The mechanical and permeation behavior of DuPont’s SeaGel® carrageenan/starch based film formulation were investigated and compared to gelatin based films. More specifically, the present study characterizes the influence of relative humidity and temperature on oxygen and water vapor permeability of the films.

The films in this study were made either from a blend of carrageenan, a secondary film former and plasticizers (i.e. DuPont’s SeaGel® Technology) or a blend of gelatin and plasticizers. Oxygen permeability measurements were performed according to ASTM method D3985. Water vapor transmission rates (WVTR) of selected films were measured using a MOCON Permatran-W 3/33 (Moden Controls, Inc., Minneapolis, MN, USA) and the method as described in ASTM F1249-90. Water sorption characteristics of films were measured using a dynamic vapor sorption (DVS) analyzer by Surface Measurement Systems (Allentown, PA, USA). Film puncture strength and distance were measured on a texture analyzer (Model TA.XT2, Texture Technologies, Scarsdale, NY) equipped with a 25-kg load cell. Film tensile modulus and strength were measured according to American Society of Testing and Materials Standard method D638.

The equilibrium moisture content of the SeaGel® Technology and gelatin films generally increased with increasing relative humidity and decreased with increasing temperature which leads to lower density and higher oxygen and moisture permeation. Gelatin film had higher residual moisture (bound water) than that of SeaGel® film

Oxygen permeability experiments were performed using ASTM method D3985 with 0% to 80% relative humidity at various temperatures. Oxygen permeation of SeaGel® Technology films showed similar performance as gelatin film and increased with increasing relative humidity. The water vapor transmission of both SeaGel® Technology and gelatin films increased with increasing relative humidity but following different functional form. The WVTR of gelatin film was slightly lower than previously reported by Martucci and others (1, 2, 3). This can be explained by the higher MW and thicker film those authors used.

It has also been found that dried SeaGel® film has higher tensile strength and greater elongation than that of wet film. Additionally, dried SeaGel® film has higher tensile strength than that of the gelatin film (strain <500%).

In summary, a statistical model is developed to predict the permeability of SeaGel® and gelatin films as a function of thickness, relative humidity and temperature. The equilibrium moisture content of SeaGel® Technology films and gelatin film increased with increasing relative humidity and decreased with increasing temperature. Oxygen and water vapor transmission of both SeaGel® Technology and gelatin films increased with increasing relative humidity. SeaGel® film demonstrated similar permeation performance as gelatin film and higher tensile strength than that of gelatin film at elongation less than 500%. These results indicate that optimized SeaGel® Technology blends can improve mechanical and permeation properties of SeaGel® Technology free films. These improvements can be beneficial to film applications such as softshell capsules, oral film strips, and film coating.

References

1. Martucci, J.F.; Ruseckaite, R.A. Tensile Properties, Barrier Properties, and Biodegradation in Soil of Compression-molded Gelatin-dialdehyde Starch Films. J. Appl. Polym. Sci. 112, 2166-2178 (2009).
2. Bae, H.J. et al. Development and Characterization of PET/Fish Gelatin-Nanoclay Composite/LDPE Laminate. Packag. Technol. Sci. 22, 371-383 (2009).
3. Avena-Bustillos, R.J. et al. Water Vapor Permeability of Mammalian and Fish Gelatin Films. J. Food Sci. 71, E202-E207 (2006).