RXL® Ultra: Unlocking the potential of botanical softgels

February
04, 2025

4 min

#AmazingGelatin

Herbal supplements are continuing to grow in popularity, driven by consumers seeking wholesome options for everything from immune support to cognitive health. Botanical ingredients can offer numerous and invaluable health benefits for digestion, skin and cardiovascular function, for example. In fact, supplement launches with botanical ingredients have shown the strongest growth compared to launches of botanicals in food and beverages, with a compound annual growth rate (CAGR) of six per cent between April 2019 and March 2024 [1]. Here, gelatin softgels are a preferred delivery format. However, manufacturers face a major challenge with softgels containing plant extracts – crosslinking.

Mystery of crosslinking

Crosslinking causes a real headache in the world of softgel capsules. This natural process occurs when protein molecules in the gelatin shell interact with reactive ingredients such as aldehydes or polyphenols inside the capsule. Over time, these reactions reduce the solubility of the soft capsule, leading to longer dissolution times in the gastrointestinal tract and slower ingredient release rates. In some cases, the delay is so drastic that consumers may not experience the expected beneficial effects.

Botanical ingredients, with their rich profiles of flavonoids, tannins, aldehydes and other bioactive compounds, are particularly likely to cause crosslinking. If you’re working with extracts, such as those from blueberries, cranberries, or essential oils such as peppermint or lavender, you’re probably familiar with their strong crosslinking potential. Factors such as heat and humidity can exacerbate the problem by promoting self-crosslinking of gelatin, resulting in capsules that won’t dissolve properly. Here, our relaunched RXL^® Ultra is a game-changing solution.

Ultimate anti-crosslinking solution

Our RXL^® portfolio offers tailored gelatins designed to combat crosslinking to varying degrees. Leading the line-up is RXL^® Ultra, a specialized gelatin known as gelatin polysuccinate, derived via a modification process. Its modified structure blocks the chemical groups in gelatin responsible for crosslinking reactions. In short, it prevents the problem before it even starts.

This unique product maintains all the benefits of traditional gelatin-based softgels, such as low processing temperatures, while tackling even the toughest botanical ingredients. Botanical softgels made with gelatin polysuccinate have been available on the market for years as OTC products, and we have thoroughly tested them to confirm their effectiveness and reliability. In fact, tests show that softgels made with RXL^® Ultra can release ingredients such as peppermint or lavender oil within minutes, while standard gelatin capsules may struggle to release their contents at all.

RXL^® Ultra delivers convincing, reliable performance, ensuring that consumers receive the full benefits of their supplements. From a regulatory perspective, gelatin polysuccinate has a solid history of over 50 years of safe use in pharmaceutical and medicinal products in the EU, UK, Korea and Japan, serving as an excipient in capsule material or as an API in blood plasma expanders.

Looking ahead: The future of RXL^® Ultra in supplements

However, gelatin polysuccinate isn’t yet approved for use in food supplements. Due to its chemical modification, it does not fit into the standard definition of ‘gelatin’, and therefore requires approval as a food ingredient before it can be used as capsule material in food supplements.

But the good news is our team is actively working to get this innovative gelatin product sanctioned for use in food supplements across the EU and other key markets. Once achieved, the possibilities for plant extracts in softgels could be huge, providing manufacturers with an effective solution to one of the industry’s biggest challenges.