The industry is constantly searching for innovative and sustainable solutions for formulating dietary supplements. Tablet film coatings play a crucial role in the stability, release, and acceptance of oral dosage forms. While synthetic polymers have long dominated, natural polymers are gaining increasing importance due to their biocompatibility, biodegradability, and the growing demand for resource-efficient production methods. Pectin and alginates are two examples of natural polymers that offer versatile applications as film coatings, suitable for both immediate-release and enteric-coated formulations.
Extraction and Properties of Pectin and Alginates
Pectins are complex polysaccharides rich in galacturonic acid. They are primarily extracted from the peels of citrus fruits (lemons, oranges, limes) – byproducts of the food industry that would otherwise be discarded. This origin highlights pectin’s sustainable character. Chemically, pectin mainly consists of chains of α-(1→4)-linked D-galacturonic acid units, which are partially esterified with methyl esters. The degree of esterification significantly influences its properties, especially its solubility and gelling ability. Pectin is known for its ability to form gels in the presence of divalent cations (e.g., Ca2+), which is advantageous for enteric coatings. In short, high ester pectin shows immediate-release dissolution behavior, while low ester pectin can be used for enteric coatings.
Alginates – Alginic acid is an edible, naturally occurring polysaccharide found in brown algae. For coating purposes, sodium alginate is used. One of the most commercially important sources is the species Laminaria hyperborea. Extraction from sea algae represents another sustainable resource, as algae grow quickly and don’t require agricultural land. Similar to pectin, alginates form strong gels in the presence of divalent cations, which makes them ideal for use in enteric-coated formulations.
A well-known provider of alginates and pectins is IFF Pharma Solutions now part of Roquette.
Positive Properties and Applications
Both pectin and alginates offer a range of advantageous properties for tablet film coatings:
- Biocompatibility and Biodegradability: As natural polymers, they are excellently biocompatible and are naturally degraded in the body, which can lead to lower toxicity risks compared to some synthetic polymers.
- Versatility in Release Control: Immediate-Release Coatings: With specific formulations and the right degree of esterification (for pectin) or modification of the chain structure (for alginates), both polymers can also be used for immediate-release coatings. The goal here is to protect the tablet’s integrity while it rapidly disintegrates in the gastrointestinal tract and releases the active ingredient. Their good film-forming ability and adhesion properties contribute to a smooth and stable coating that is also aesthetically pleasing. Enteric Coatings: Pectin and alginate have the ability to remain stable in an acidic environment (stomach) and only release the active ingredient in the neutral to slightly alkaline environment of the intestines. This protects acid-sensitive active ingredients from degradation in the stomach and prevents gastric irritation caused by certain substances.
- Improved Swallowability and Taste Masking: A smooth film coating improves aesthetics and makes swallowing tablets easier. Additionally, coatings can mask unpleasant odors or tastes of active ingredients.
- Resource Conservation and Sustainability: Extraction from renewable raw materials (plant waste, algae) makes pectin and alginate a more environmentally friendly alternative. This reduces dependence on petrochemical resources and contributes to a circular economy by giving waste products a new value.
Use in Dietary Supplements
In the field of dietary supplements, natural ingredients are particularly in demand. Consumers increasingly prefer products that are considered “clean label” and free from synthetic additives. Pectin- and alginate-based coatings perfectly fit this trend. They not only enable the controlled release of important vitamins, minerals, or plant extracts, but also contribute to the positive image of the product. For acid-sensitive probiotics or enzymes, enteric coatings based on these polymers are essential to ensure that the active ingredients reach the intestines intact.
Ready-to-Use Film Coating Systems
The development and formulation of film coatings can be complex. Companies like BIOGRUND offer “ready-to-use” products for this purpose, such as the AquaPolish® and NutraPolish® systems. These products are pre-formulated mixtures that can be tailored to specific customer requirements. They enable dietary supplement manufacturers to apply high-quality film coatings efficiently and reproducibly, without having to undertake extensive development work themselves. The ability to offer customized and, in some cases, talc-free formulations underscores the flexibility and the trend towards cleaner and more targeted formulations. Talc, a commonly used filler and lubricant, is avoided by some consumers due to concerns about potential contamination, which further drives the demand for talc-free alternatives.
Conclusion
Natural polymers like pectin and alginates are suitable alternative components for developing modern, functional, and sustainable tablet film coatings. Their versatility in controlling active ingredient release, their biocompatibility, and their contribution to resource conservation make them ideal candidates for the booming dietary supplement market. With the advent of specialized “ready-to-use” solutions like those from BIOGRUND, implementing these sustainable technologies in production becomes even easier and more accessible, paving the way for a greener and more efficient future for oral dosage forms.
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Source: BIOGRUND, website (31) Natural Polymers for Tablet Film Coatings: Pectin and Alginates as Sustainable Alternatives | LinkedIn
