Lively Liposomes

wimagine - stock.adobe.com

Nutraceutical formulators have a variety of delivery systems they can leverage to increase ingredient efficacy or decrease dose size. This is often based on the particular active being used, some of which are more difficult to work with than others. Emerging solutions like liposomes are disrupting the delivery mechanism space with superior technology that renders benefits for formulators and consumers alike. Liposomes offer considerable advantages for formulators, from increased bioavailability to targeted delivery and more. As liposomes rise, it’s important for formulators to understand how these molecules work and when it’s advantageous to use them. Here’s what nutritional supplement formulators need to know about liposomes.

What are Liposomes?

A liposome is a sphere-shaped vesicle composed of phospholipid bilayers. George Kokkinis, CEO and founder of Pharmako Biotechnologies (Frenchs Forest, Australia), says liposomes are designed to mimic cell membranes, which makes them effective for delivering therapeutic agents to specific cells or tissues in the body.

“Liposomes are used (in medicine) to enhance the bioavailability and stability of medicines, reduce side effects, and improve targeting to diseased tissues,” Kokkinis notes. “Their structure can vary in size and composition, allowing for versatile applications in medicine, cosmetics, and biotechnology.”

While liposomes are often confused with micelles and microencapsulation, Kokkinis notes that the technologies are quite different. Whereas liposomes have a bilayer membrane with an aqueous core, micelles have a single-layer membrane with a lipid core. Microencapsulation, in contrast, is generally comprised of a solid layer around a liquid droplet. Kokkinis says that microencapsulated ingredients are generally about a thousand times larger than micelles and liposomes.

Sebastian Balcombe, MS, is a medicinal chemist and the founder & CEO of Specnova (Tysons Corner, VA). Balcombe says that true liposomes are precision-oriented structures that can deliver bioactives into the bloodstream, where they can reach their targets with higher concentrations.

“The strength of the liposomal delivery system is that it works in a way that the body naturally prefers to absorb nutrients – with a lipid encasement that protects the payload as it moves through the GI tract,” Balcombe says. “This arrangement enables nutrients to penetrate the epithelium of the small intestine for intact delivery into the bloodstream. An effective liposome optimizes nutrient absorption through the GI tract, increasing its concentrations in blood plasma and optimizing bioavailability in the target tissue.”

When is it Beneficial to Use Liposomes?

Kokkinis says that liposomes are generally used to deliver active ingredients in a targeted manner, such as targeting specific cells or tissues. This makes liposomes ideal when an ingredient needs to be delivered to a specific site in the body to function best. Furthermore, liposomes help to improve the bioavailability of ingredients, which can make them ideal for use in cases where the ingredient in question offers poor solubility. Kokkinis also notes that liposomes can reduce the toxicity of an active ingredient, which can be advantageous when the ingredient in question has poor tolerability.

Balcombe notes that liposomes help to improve permeability and stability of ingredients in the body; he explains that most natural ingredients with low bioavailability will benefit from liposomal encapsulation. However, he says, even ingredients with generally good bioavailability will benefit from liposomal encapsulation.

There are several ingredients that can benefit from liposomal encapsulation. For example, Balcombe says that vitamin C is a good candidate for liposomal encapsulation. “Specnova has a published clinical study1 showing that Specnova’s VitaSomal Vitamin C is 27% more bioavailable than non-liposomal Vitamin C, and 20% more VitaSomal Vitamin C was found in white blood cells compared to non-liposomal Vitamin C,” he explains.

Other ingredients that can benefit from liposomal encapsulation include berberine, quercetin, CoQ10, and hyaluronic acid. Meanwhile, Kokkinis notes that liposomal technology continues to improve, which makes this delivery system more flexible and adaptable.

“Methods of easily producing liposomes in mass scale, like microfluidics and high-pressure homogenization, are now available,” Kokkinis says. “Stimuli-responsive liposomes can release their cargo after a specific trigger, like the application of a magnetic field or ultrasound. Furthermore, liposomal technology is improving its stealth capabilities – its ability to avoid the immune system – by incorporating various specific molecules into the bilayer membrane.”

How are Liposomes Authenticated?

As liposomes gain popularity in the nutraceutical space, bad actors are cropping up, offering counterfeit liposome products that claim to have all the benefits of true liposomes, but with none of the science to back up the hype. As such, it’s critical for formulators to understand how liposomes are authenticated and when claims are too good to be true.

Balcombe says that the issue of misrepresentation regarding liposomal products is a significant concern in the industry. Specnova has tested over 95% of the industry’s liposomal ingredients, he explains, and has found that very few of them contain true liposomes.

“Part of the problem is that the production of genuine liposomal formulations requires precise manufacturing processes and rigorous quality control measures to ensure proper formation and stability of liposomes,” explains Balcombe. “That’s why we spend so much time verifying and validating true liposomes, which are how our TruLiposome Verified seal came into being.”

Specnova uses six different technologies to validate liposomes. The first is a cryogenic transmission electron microscope, or CryoTEM. Balcombe says this is the backbone of liposome testing, as it shows the inside of the liposome. Next, a scanning electron microscope shows the outside of the liposome, while dynamic light scattering measures the liposome’s average size. Specnova leverages zeta potential measurement to determine encapsulation efficiency, which refers to how much of an ingredient is inside the liposome as opposed to outside it. Powder x-ray diffraction is used to check for crystallization and components of the liposomal formulation. Finally, an optical microscope is used to check the dispersion of the formulation.

“All of these tests need to be completed to show the accurate picture of a true liposome,” Balcombe says. “One test on its own cannot effectively validate a liposome. Each test provides a different piece of information that has strengths and weaknesses. Only when all the tests are combined is it possible to establish liposome validation.”

Kokkinis says there are also several other methods for verifying liposomes. For starters, he explains, a true liposome will be a water-like liquid. Any ingredient that is presented as a powder or syrup will not contain true liposomes. In addition to the physical characterization methods described above, there are several other tests that formulators can run to ensure they’re dealing with true liposomes. Kokkinis notes that chemical composition analysis can help to ensure liposomes are authentic; this can include high-performance liquid chromatography to analyze the lipid composition and verify the presence of specific lipids, as well as nuclear magnetic resonance spectroscopy to assess lipid structure and composition.

Kokkinis also says that encapsulation efficiency testing can help to confirm that a liposome is authentic. “Assessing how much active ingredient is encapsulated can indicate whether the product is indeed a liposome,” he explains. “This can be measured by separating unencapsulated material using an ultracentrifuge and quantifying the remaining active ingredient.”

Furthermore, he adds, stability testing can reveal whether a liposomal ingredient is authentic. Genuine liposomes should exhibit stability under specific storage conditions; stability tests can include freeze-thaw cycles, temperature variations, and light exposure.

Finally, liposomes can be authenticated by studying the release profile of the encapsulated active ingredient. Liposomes typically exhibit controlled release compared to free formulations.

Kokkinis says there are also several signs of non-liposomal products that formulators should pay attention to.

He notes that “formulators can understand when a product may not be a genuine liposome by looking for signs such as inconsistent size distribution, poor stability, lack of encapsulation, and the absence of lipid composition.”

When are Liposomal Claims Too Good to Be True?

There are several key signs that formulators should watch for to determine when liposomal claims don’t pass muster. Kokkinis notes that in general, liposomes can only carry a small amount of active ingredient. Hydrophilic liposomes can generally achieve 20% concentration, while lipophilic liposomes can achieve up to 1% concentration. If a formulator claims that their liposomal ingredient has a 70% concentration, for instance, it’s a red flag.

Furthermore, the ingredient format is something formulators should pay attention to. If a liposomal ingredient is marketed as a powder, it may be too good to be true.

“Liposomes presented as powders should be taken with caution,” Kokkinis says. “True liposomes require water to maintain their circular, bi-layer structure. Removing the water, for example, by spray drying, creates a dry phospholipid ball that crumbles apart. Also, the high temperatures involved in spray drying tend to destroy these structures and the actives.”

The exception to the powder rule, Kokkinis notes, is pro-liposomes. Pro-liposomes contain the usual ingredients that make up a liposome, but once introduced to water, they spontaneously form a liposome.

Finally, Kokkinis says that any claim around a liposome offering 100% bioavailability is misleading. He explains that while liposomes do improve bioavailability, there are still some limitations that even liposomes cannot overcome.

Balcombe notes that ingredient manufacturers claiming high bioavailability should be able to share study results proving the claims.

“There are companies in the industry that claim their liposomal ingredients are however many times more bioavailable than non-liposomal ingredients; sometimes the reported numbers are very high for ingredients that are already bioavailable and should not show a double-digit increase in bioavailability,” he explains. “Unless the liposomal manufacturer can share the testing results and the actual research, you should be skeptical.”

Liposomes on the Rise

Liposomes offer substantial advantages for formulators, from increased bioavailability to improved ingredient stability and beyond. However, the growing popularity of liposomes has prompted some bad actors to create counterfeit liposomes that offer none of the benefits of true liposomes. Formulators should exercise caution and perform due diligence checks to ensure they’re sourcing true liposomes from reputable suppliers. With authentic liposomes, formulators can increase the bioavailability of their ingredients while reducing toxicity and boosting stealth capabilities.

Mike Straus is a freelance writer living in Kelowna, Canada. He writes for trade publications like Hoist, Canadian Chiropractor, Grow Opportunity, and Massage Therapy Canada.

References

1. Purpura, M.; Jäger, R.; Godavarthi, A.; Bhaskarachar, D.; Tinsley, G.M. Liposomal delivery enhances absorption of vitamin C into plasma and leukocytes: a double-blind, placebo-controlled, randomized trial. Eur J Nutr. 2024, 63 (8), 3037-3046. DOI: 10.1007/s00394-024-03487-8