A Novel Method for Encapsulating Nutritional Supplements within Edible Films

Abstract

Many nutritional supplements are hydrophobic solids or oils that are extremely difficult to administer in tablet form. These supplements are often consumed as large soft gels that may represent a choking hazard. In addition, many nutritional supplements produce an aversive taste or tactile response when consumed orally. Because of these limitations, improved delivery methods for administering nutritional supplements to the oral cavity represent an important goal. In this study, vitamin E acetate is exploited as a model nutritional supplement for developing an improved oral delivery method by encapsulating this vitamin within rapidly dissolving edible films. Vitamin E acetate was solidified by mixing this oil with a long-chain fatty alcohol. The resulting wax was then pulverized and added to an aqueous polymer solution that included melted gelatin. The mixture was then sonicated to form a stable emulsion that was dried to a thin, flexible film. Vitamin E acetate was successfully encapsulated within films at amounts that approximated the minimum daily requirement for this supplement. Minimal loss of this vitamin occurred when the emulsion was dried to a film. Average film thickness was 150 µmeters, and the encapsulated vitamin E was not degraded. Film formulations that included the excipients sucralose and peppermint oil produced taste intensity ratings in the moderate range, and displayed favorable hedonic responses. In summary, rapidly dissolving edible films have been developed that greatly increase the load capacity of a hydrophobic oral supplement. These edible films represent a promising approach for delivering hydrophobic oils or solids to the oral cavity at bioavailable amounts.

Highlights

Edible films can be loaded with a hydrophobic compound at high amounts.
Edible films have been prepared that encapsulate vitamin E acetate.
Edible films that include vitamin E and excipients exhibit moderate taste intensity.
Edible films that include vitamin E and excipients exhibit positive hedonic scores.
Vitamin E-containing films are flexible with thicknesses near 150 µmeters.

Introduction

An improved delivery method for administering nutritional supplements and medications to the oral cavity at bioavailable amounts represents an important goal for improving human health. One reason that many new drug formulations have not succeeded is because of their poor solubility in water.1 Due to this poor solubility, 70-90% of drug candidates and 40% of marketed drugs suffer from inadequate bioavailability. A second reason for developing an improved delivery method is that many medications have both an aversive tactile response and an aversive taste response. These aversive responses may decrease compliance, especially in young children.Thirdly, an oral delivery system that minimizes choking hazards would further increase compliance.8 Finally, a delivery system that allows sublingual delivery of pharmaceutical agents would be useful for compounds that are degraded in the gastrointestinal tract,9 which in turn could increase bioavailability.

Because of its anti-oxidative and photoprotective properties, vitamin E is widely used as an active agent in both pharmaceutical and cosmetic products. This essential vitamin serves as a lipophilic antioxidant. This supplement also supports the immune system and may help fight chronic diseases. Alpha-tocopherol is the most abundant form of this vitamin and represents its most biologically active form. Also, esterified derivatives of α-tocopherol increase the stability and shelf life of this supplement. These properties all indicate that vitamin E acetate represents an excellent model supplement for developing improved oral delivery methods.

Vitamin E is a hydrophobic oil that is most commonly consumed as soft gels. More recently, liposomes, lipid nanoparticles, and micelles have been developed for delivering Vitamin E to the oral cavity. Naghibzadeh and coworkers prepared chitosan nanoparticles that successfully encapsulated α-tocopherol. Chitosan-specific micelles have also been prepared from oil-water emulsions. Finally, zein/chitosan complexes have been prepared that encapsulate α-tocopherol for delivery to the GI tract. In addition, edible films represent a promising oral delivery method. However, this delivery method severely limits the amount of pharmaceutical agent that can be incorporated within films. Finally, many formulations for packaging vitamin E require specialized equipment or require toxic solvents that could limit human testing. However, oral bioavailability of vitamin E can be increased by complexing this compound with a saturated long-chain fatty alcohol to generate a solid.33 In this study, a hydrophobic solid is then emulsified and subsequently encapsulated within edible films. This study describes the development and characterization of edible films that contain dramatically increased amounts of vitamin E acetate.

Materials

Edible films were prepared as previously described. Briefly, pullulan (α-1,4-; α-1,6-glucan; NutriScience Innovations, LLC, Trumbull, CT) was used as the water soluble polymer. Food coloring (McCormick & Co., Hunt Valley, MD) was obtained from a local supermarket, and was added to aid in visualizing edible films. Water was obtained from Deer Park (Stamford, CT), sucralose was from Sweet Solutions (Edison, NJ), and glycerol was from Fisher Scientific (Hampton, NH).

Gregory Smutzer, Omar Elamin, A Novel Method for Encapsulating Nutritional Supplements within Edible Films, Journal of Pharmaceutical Sciences, 2025, 103706, ISSN 0022-3549,
https://doi.org/10.1016/j.xphs.2025.103706.