Doc. Ing. Petr Kaštánek, PhD.
Vitamin C (L-ascorbic acid) is one of the most important vitamins. It significantly affects the activity of a number of main regulatory systems in the body, namely nervous, endocrine and immune. Humans cannot create vitamin C and must therefore obtain it from food or from dietary supplements. Vitamin C contributes to the normal function of the immune system, reduction of fatigue and exhaustion, protection of cells from oxidative stress, normal mental activity, normal activity of the nervous system, normal collagen formation for the normal function of blood vessels, bones, cartilage, gums, skin and teeth, normal energy metabolism and regeneration of the reduced form of vitamin E
The encapsulation of bioactive substances in liposomes , originally limited to the field of pharmaceutical preparations, is currently one of the most modern trends in the nutraceuticals and functional cosmetics sectors, as it can offer increasingly aware customers products with high bioavailability and long stability of bioactive substances, formulated using more modern scientific and technological knowledge.
Liposomes are spherical vesicles consisting of one or more concentric phospholipid bilayers that surround a core formed by water or an aqueous solution of hydrophilic substances (in our case, vitamin C). Since liposomes are non-toxic and biodegradable, they represent an effective delivery system for a number of drugs and nutraceuticals. In clinical studies, liposomes have been reported to improve the therapeutic efficacy of drugs by stabilizing compounds, overcoming barriers to cellular and tissue uptake, and increasing biodistribution of drugs to target sites while minimizing systemic toxicity.
Effective oral administration of vitamin C requires reducing the rate of its degradation in the intestine and facilitating its absorption. Vitamin C is usually administered orally in crystalline form or as a solution, which makes it susceptible to degradation in the gastrointestinal tract, especially in the presence of metal ions. Degradation of vitamin C can be effectively reduced by binding it to a hydrophilic-hydrophobic interface, which can be provided by lipid aggregates such as liposomes. They reduce the degradation of vitamin C in the gastrointestinal tract, slow down its release and increase absorption. Liposomes also alleviate possible disturbances in the function of the gastrointestinal tract, which allows the application of higher doses of vitamin C for a longer period of time. In addition, it cannot be overlooked that lipids, especially phosphatidylcholines, are an important component of a balanced diet.
The problem with the market for liposomal preparations is its very rapid expansion. Thanks to this enormous speed, quality standards have not yet been set in terms of encapsulation efficiency and other characteristics. The quality of liposomes significantly depends on the production technique. The manufacturer of the preparation must have advanced instrumental imaging and analytical techniques available to quantify key characteristics of encapsulated particles, such as particle size (often in the order of hundreds of nanometers) or polydispersity index, as well as techniques and equipment that determine product stability and bioavailability of the active substances. However, this information is not normally communicated to the consumer, nor are these parameters measured in most commercially available products.
The current nutraceutical market with liposomal products (especially liposomal vitamin C) is not only growing very quickly and dynamically, but especially due to technological and professional demands, it is very difficult for the average consumer to understand. This also entails a large number of products accompanied by exaggerated or even false claims, which are often difficult to navigate even for professionals.
Currently, there are two types of liposomal products on the market, it is in liquid form and in powder form.
Although liquid liposomal preparations are user-friendly, they are characterized by a number of technological problems - to ensure microbial protection of the preparation, it is necessary to add alcohol or preservatives, which makes the product unsuitable for children or people sensitive to alcohol. The products also typically have a limited shelf life and cold storage is usually necessary after opening the product. The unpleasant taste is often suppressed by the high sugar content, which makes the preparation unsuitable for children and diabetics, or does not correspond to the principles of healthy nutrition. Liposomes in liquid form can change over time in size, structure, character from uni- to multi-lamellar, etc., which can also lead to a change in the stability and biological activity of the preparation. In some brands of products, liposomes are not present at all, or there are only minimal amounts, and most of the vitamin C may be present in the solution around the liposomes!
However, there are also problems with the powder form of preparations available on the market: some brands simply dry-mix powdered phospholipid with a powdered dietary supplement (ascorbic acid) and call the resulting mixture liposomal, while there are no liposomes in the material, nor are they formed spontaneously in significant quantities in the digestive tract after ingestion of such a mixture. Such preparations can be characterized by a significantly lower price, but their effect on the body is no different from normal vitamin C. Some manufacturers also pass off organic salts of ascorbic acid, such as ascorbyl palmitate, as liposomal form. The classic route leading to the creation of a functional preparation is an expensive procedure, where ascorbic acid and phospholipids (or lecithin) are first dissolved together, a liquid liposomal mixture is created using a suitable technique and then dried using a gentle technique, such as spray drying, where the droplets of the solution are exposed to higher temperature for only a fraction of a second, and the decomposition of sensitive vitamin C is thus prevented. spontaneously form liquid liposomes. It is therefore obvious that such a production process is technologically demanding and expensive.
So what should you look out for when buying as a consumer and how can you recognize quality liposomal vitamin C?
If the preparation really forms liposomes in the digestive tract, only an expert can tell with the use of advanced equipment, such as an electron scanning microscope. But you can also stay vigilant yourself - watch out for suspiciously cheap products. Liposomal technology, as indicated above, it is expensive and this is reflected in the higher price of preparations. He buys from proven, traditional brands, backed by real experts from the academic sphere. Look for lecithin or phospholipids that are present in lecithin in the ingredients. These create the structure of the liposome, without them it is not a liposomal (or pro-liposomal) preparation.
Fig. 1: Photo of the powder liposomal structures of NEOLIPO C from a transmission electron microscope.