How to choose an ingredients-delivery system

From common tablets to new-tech edible films, the range of nutrient-delivery options for formulators offers greater formulation challenges, but can also create new product opportunities and significantly expand consumption of functional nutrients. Daniel Murray summarises the options and demands of each

Consumers are now being exposed to an increasing number of delivery systems for nutritional and functional ingredients. Ingredients manufacturers certainly want to see as many finished-product forms as possible to enhance sales. Meanwhile, marketing companies often see delivery systems as another way to distinguish their products from competitive offerings. However, before drawing up the marketing plans and checking with regulatory, keep in mind that not all ingredients are suitable to all delivery systems. Knowing the ingredient characteristics will help guide you through the process of choosing which delivery systems may be used to create a unique and stable finished product.

When considering the various delivery systems for nutritional ingredients, it's essential to know as much as possible about the formulation characteristics of the ingredient or mixture. Questions to address include whether the ingredient is stable, hygroscopic, soluble and bioavailable. Some delivery systems are quite forgiving and protective of sensitive ingredients (capsules and sachets), while others can be harsh and inhospitable (beverages). Reviewing delivery-system options requires some technical applications knowledge and experience. Following is an overview of common systems and their advantages and disadvantages.

These are so commonly used and economically efficient, they are generally underappreciated for the amount of formulation science required. Granulated ingredients work better than fine powders and stable, nonhygroscopic ingredients will yield significantly better finished tablets than less-stable ingredients. Typical problems include pitting, friability (crumbling), and capping (when the tablet separates into a top and bottom layer). Ingredients with hygroscopic tendencies may lead to pitting or inconsistent surface quality; however, excipients and lubricants will also influence tablet integrity. With few exceptions, better-quality ingredients and excipients will yield better-quality tablets. While tablets may not offer product differentiation, they are a stable and cost-effective delivery system and may be run in relatively small volumes.

Two-piece, and liquid-filled capsules and softgels
Two-piece capsules offer the easiest way to deliver challenging dry ingredients. There is significantly less stress on the ingredients and generally more room for larger payloads of active ingredients. Many feel capsules have a 'pharmaceutical elegance' compared to tablets, as well as offer creative visual options such as colour choices and logo placement. Softgels and liquid-filled capsules offer a neat and clean delivery system for fats, oils and highly soluble ingredients. These systems also are a solution for hygroscopic ingredients that will continually absorb moisture from the environment. There are a limited number of production facilities that offer softgels and liquid-filled capsules, but those that do are generally experts at ingredient formulation.

Time-release and sustained-release systems
These are delivery mechanisms experiencing rapid growth and interest. Using a variety of technologies such as coatings, encapsulation or wax matrixes, you can delay the release and the absorption of an active ingredient and potentially improve its bioavailability. Theoretically, this may be used to offset the poor absorption characteristic of certain ingredients, or allow a reduction of inclusion rates of high-dose ingredients. An ingredient targeting satiety or endurance, for example, may offer improved benefit from a prolonged metabolic presence vs a rapid uptake followed by a rapid elimination.

While an ingredient may benefit biologically from a slow-release delivery system, it may not commercially support the expense of the additional technology, and not all ingredients are chemically suited for the system matrix. When considering a sustained-release delivery system, it's important that the final absorption or delivery can be analytically verified. This may require additional testing or even the identification of a biomarker to confirm system benefit. Most stable, nonhygroscopic ingredients can be included in a sustained-release delivery system.

SmoothiesBeverages, smoothies and juices
Beverages have clearly seen robust growth as a delivery system for nutritional ingredients. Functional beverages, smoothies and juices have been well accepted by consumers and offer an excellent alternative to tablets and capsules. Unfortunately, formulating a functional beverage is a virtual minefield, and requires significant resources and bench work to characterise the ingredient. Knowing solubility limits and conditions, stability in low pH environments, and even possible reactions to specific acidulates are all critically important. Ingredients that precipitate to the bottom or leave a coloured ring at the top of the beverage bottle are certainly problematic. Instability and continuing reactions often lead to oxidation and colour issues long after the product has left the production facility.

Heat stability is another important characteristic. At some point in the production run, most beverages go through a heat process before bottling. It may be 'pasteurisation,' or 'hot filling' in the case of a juice or sports drink. Temperatures can reach 180ËšF in a hot-filling process and this may be enough to damage certain ingredients, especially in a liquid state. Significant bench work is required before knowing if an ingredient is suitable for beverage application.

Unlike tablets and capsules, beverage ingredients must be taste friendly. Simply put, 'taste is king.' A poor-tasting product will rarely be commercially successful.

EffervescentsSachets and effervescents
Effervescents and sachets (single-serving packs similar to a sweetener packet or stick) are refreshingly different and highly sought after by consumers. These two systems are usually stable at room temperature, easily transportable in a pocket or purse, and can be applied to a variety of beverages. Sachets are exceptionally adaptable in application and can be added to yoghurts and other foods, which helps reduce flavour fatigue when faced with consuming a flavoured product in a (recommended) daily routine. These two systems are also friendly to high-dose ingredients and, anecdotally, solubility seems less an issue when consumers add the mixture.

Like beverages, effervescents and sachets are complex and cost sensitive. After overcoming the formulations hurdles of taste and compatibility, sachets require double packaging and large production runs. Production costs tend to escalate quickly and the finished product is sold in a limited number of servings to keep prices reasonable.

Gummy bearsSoft chews and films (oral strips)
Soft chews, gummies and films are also trendy delivery systems, offering yet another alternative to tablets and capsules. These systems provide effective application for child supplements and oral-care products. Limited-production facilities may require more planning and resource allocation than previously mentioned delivery systems.

Soft chews generally run about 5g in weight with 25-35 per cent of that volume available for the active ingredient(s). They easily accommodate fats, oils and insoluble powders, and can be taste-masked if unpleasant flavours or odours are a problem. Micro-encapsulated ingredients are frequently used in soft chews for improved stability. Review packaging requirements and shelf life when considering soft chews as a delivery system.

Films are a high-tech delivery option for speciality, low-dose nutritional ingredients. A film serving tends to run between 40mg and 110mg in weight, with 30-40 per cent of this weight available for the active ingredient(s). Polymers are used to 'complex' and stabilise the active in the finished-product matrix. High-quality packaging is important for stability and, like sachets and effervescents, a seven-to-10-day supply is typical vs a 30-to-60-day supply.

Future technologies
Looking forward, future ingredients-delivery systems may include further 'upstream' technologies. Developments such as microencapsulation, nanotechnology and chemical modulation are well under way, and may provide an inherent advantage similar to today's mechanical delivery system. As an example, complexing with cyclodextrins or nanotechnology may significantly increase bioavailability of an active. While this advanced technology is ultimately about delivery, it's more about ingredient preparation and form, and will still be subject to the choice and limits of the delivery system.

Today's formulators have numerous options for delivery systems. Simple tablets and capsules often offer the best value for consistent, cost-effective delivery of nutritional ingredients. Time-release and sustained-release systems may offer specific advantages for ingredients that face rapid absorption or poor bio-availability but they require more preparation, processing and testing before benefits can be confirmed.

More modern delivery systems include functional foods, beverages, powders, chews and films. They are more complex and subject to greater formulation challenges, but they create wonderful new product opportunities and significantly expand consumption of functional nutrients.

Daniel Murray is vice president of business development at New Jersy-based Xsto Solutions, which specializes in jointly developing and implementing new-product sales and marketing strategies for speciality nutritional ingredients to the dietary-supplements, food and beverage industries. He has held positions in technical development, sales, marketing and product development with Roche Vitamins, Rhodia Food, Lonza and InterHealth.
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