MANY SHAMPOOS, lipsticks, face creams, and even toothpastes contain minute envelopes with tiny molecular messages inside. Designed as a small-scale mail system, these envelopes protect and deliver active ingredients that might otherwise degrade or get lost before they get to their intended destinations.
Lately, these envelopes, called encapsulants, have become part of elaborate new systems with street smarts. Whereas they once deposited contents such as vitamins, botanicals, and emollients when broken open with friction, now they meter out skin-enhancing ingredients in a variety of sophisticated ways. The presence of moisture in the skin might serve as the trigger, or it could be the change from the basic pH in the bottle to the acid environment on the skin. Even bacteria that occur naturally on the skin could be what breaks open some of these microcapsules.
Among the specific products that have been developed are color-carrying particles in lotions or aftershaves that rupture as they are rubbed onto the skin and thereby deposit an instant tan. Another type of microencapsulant, this one designed for use in toothpastes to carry flavors and antibacterial ingredients, provides a burst of mouth-tingling flavor and may help banish periodontal difficulties.
Some of these innovations are courtesy of small firms that have developed novel approaches to encapsulating cosmetics' active ingredients. Among these firms are the Israeli-based Tagra Biotechnologies, Brazil-based Buntech Advanced Compound Technology, California's Aquea Scientific, and South Korea's BioSpectrum.
Established personal care suppliers are consolidating their hold on encapsulation technology positions as well. International Specialty Products, for instance, purchased U.K.-based encapsulation specialist Hallcrest in 2004. Then last year, ISP acquired Germany-based geniaLab's line of encapsulated products for personal care and formed an alliance with geniaLab to further develop encapsulant technology.
Earlier this year, Amcol's health and beauty solutions business acquired Cardinal Health's microsponge product line and the relevant technology for delivering active ingredients in dermatological products such as lotions and ointments.
EVEN THE LARGEST firms are getting into the act. Dow Chemical is planning to introduce an encapsulating technology within the next 12 months, and Rohm and Haas is working to develop encapsulating technology of its own.
Simple encapsulant systems "have been around for years, but they have recently become more sophisticated," says Meyer R. Rosen, who heads Interactive Consulting and is the editor of "The Delivery System Handbook for Personal Care and Cosmetic Products." Encapsulants are "a growing area of cosmetic science. As the number of costly active ingredients increases, delivery systems are becoming an essential way to deliver the benefits active ingredients offer," Rosen says.
"Encapsulants are a good way to preserve the activity of a given ingredient," explains Ralph Macchio, senior vice president of research at Coty, a global cosmetics formulator with its headquarters in New York City. Macchio rates recent advances in encapsulation systems as "incredible," adding that they are an improvement over the first cell-like liposomes designed to shelter active ingredients.
Those early encapsulants, which were intended to separate ingredients that otherwise do not mix well, broke down in formulations before they could deliver their contents to their intended targets, Macchio recalls. The systems on the market now are safe, effective, and used in a wide variety of toiletries, color cosmetics, skin care products, and antiperspirants, he says.
Available at increasingly attractive prices, products with encapsulant delivery systems are not limited to high-priced department store brands, Macchio points out. Personal care products sold through mass merchant outlets make use of the sophisticated delivery systems, too.
Although some encapsulation systems are more costly than others, the demand for these carrier systems is on the rise. Gillian S. Morris, chemicals and materials industry manager for the consulting firm Kline & Co., estimates the U.S. market for the carriers at about $90 million in 2006, up threefold from $30 million in 2001. And demand is still growing at 5-10% a year, she says.
Hallcrest, the encapsulation technology company that ISP bought in 2004, was one of the first firms to become involved in encapsulants for personal care, about 20 years ago, says Michael Mosquera, ISP's personal care marketing manager. The first major commerciaal application for encapsulating ingredients goes back to the 1950s when National Cash Register developed carbonless copy paper by coating the back of paper forms with an encapsulated dye, he notes. The pressure of a ballpoint pen broke the capsules, causing the dye to react with the coatings on the second sheet and produce markings identical to those on the top sheet.
Initially, the Hallcrest technology was used for bath and shower beads, Mosquera says. Today, ISP uses a phase-separation process to encapsulate hydrophobic materials including oils, lipophilic actives, dyes, and fragrances. The capsule wall is made up of equal parts gelatin and gum arabic. Like the old National Cash Register capsules, the ISP capsules rupture under pressure, releasing their contents all at once.
ISP's agreement with geniaLabs extends the encapsulating technology to include bead matrices based on biopolymers such as algin, carrageenan, and chitosan. According to Ulrich Jahnz, managing director of geniaLabs, a bead matrix formed through an extrusion process can contain up to 30% encapsulated material. In a presentation at the In-Cosmetics personal care ingredient exposition in Paris last month, Jahnz said one notable use for the beads is to enhance the appearance of a tan. A bead made of carrageenan and containing titanium dioxide and pearlescent pigments can lend a beautiful sheen to tanned skin, he said.
MANY OTHER exhibitors at In-Cosmetics also showed and discussed developments in actives encapsulation. Ralph Spindler, technical director for Amcol's health and beauty solutions business, pointed out that encapsulation systems stabilize active ingredients that otherwise might even pose explosion hazards. And although the delivery systems tend to be more costly than the active ingredients themselves, the delivery systems ensure that the actives provide a consumer benefit.
The delivery systems are especially effective in cases involving costly or unstable ingredients, Spindler noted. For instance, benzoyl peroxide, an acne medication, is a contact explosive in powder form. But incorporating the peroxide into one of the firm's methacrylate-based encapsulants effectively isolates and stabilizes it until needed.
Amcol's methacrylate-based encapsulants for cosmetics and other products include Poly-pore brand spheres, whose contents are dispensed as the spheres are squeezed. Another product line, Polytraps, releases its payload by breaking into aggregates. As the aggregates break down, they can also adsorb excess skin oil. And the company's Macrobeads exfoliating-scrub particles fracture when they are rubbed onto skin, releasing active ingredients over time as they break into smaller and smaller particles.
The methacrylate products can even be used to deliver actives on premoistened wipes, Spindler pointed out. The encapsulants, all larger than 20 µm, are engineered to sit on top of the wipe fabric and are an effective way to stabilize and deliver a wide range of materials, including the antiwrinkle agent retinol, fragrances, and volatile skin conditioners such as dimethicone.
DESIGNING an encapsulation system "is all about emulsion technology and polymer chemistry," said Uli Osterwalder, global marketing manager for active effects at Ciba Specialty Chemicals. Ciba scientists designed an encapsulation particle that is between 20 and 40 nm in diameter. The outer layer of the particle, composed of a monolayer phospholipid membrane, surrounds an inner lipid core that contains an active ingredient.
Using the Tinoderm name, Ciba markets these materials preloaded with a number of standard active ingredients such as oil-soluble ester derivatives of vitamin A or E. The Ciba products are "an improvement over liposomes, because they are smaller and more easily penetrate the skin." For products such as those based on vitamins, Osterwalder noted, "you need to penetrate the skin so that the active ingredients can have an effect."
The Ciba products increase the transport of active ingredients into the epidermis layer of the skin, according to company scientists. Esterases within the skin hydrolyze the vitamin derivatives to form free active vitamins, they say.
Degussa takes a different approach to encapsulating and delivering cosmetic active ingredients. According to Betty Santonnat, actives marketing manager, Degussa's new Tegosphere methacrylate copolymer is based on a material that the firm's pharmaceutical polymer business uses to coat tablets whose active ingredients are released only on exposure to stomach acids.
Tegospheres are stable in skin care formulations with a pH of 6.5 or higher. When they are deposited on the skin, the body's natural acid mantle, which fluctuates between a pH of 4 and 6, dissolves the coating and releases the Tegospheres' cargo. Degussa developed a special spray-drying process in which the methacrylate polymer, the skin active ingredient, and an anticlumping silica ingredient are mixed together and then dried to form particles about 20 µm in size. The firm's first product made with the new technology contains the popular antiwrinkle ingredient retinol, although Degussa is willing to make custom formulations with other ingredients, Santonnat said.
Moisture, and not pH, is the trigger mechanism for the release of active ingredients from cyclodextrins, said Marlies Regiert, business development manager for Wacker Chemie. The cylindrical molecules of cyclodextrin are hydrophilic on the outside and lipophilic on the inside. The interior cavities can therefore accommodate lipophilic ingredients and protect them against light, heat, and air until the moisture on the skin triggers their release, Regeirt explained at the Paris meeting. Her firm offers cyclodextrins incorporating ingredients such as retinol, vitamin E, tea tree oil, and linoleic oil for use in creams, gels, and foundation formulas.
The market for encapsulation technologies is so attractive that newcomers continue to enter it with novel technologies. Speaking at a seminar during the In-Cosmetics show, Michael Simmonds, applications development manager for the Amerchol unit of Dow Chemical, said Dow aims to commercialize its entry into this arena over the next 12 months.
Dow's twist is that it plans to offer the technology to customers, who can then incorporate their own ingredients, Simmonds said, adding that Dow would also not look askance at performing the encapsulation on behalf of its customers. Most providers of encapsulation technology will only custom formulate or provide standard encapsulated ingredients for customers.
Simmonds said Dow's technology is based on vesicles that form when copolymers of ethylene oxide and butylene oxide surround actives. Initial work on the technology came from a research collaboration between Dow's corporate R&D arm and the University of Michigan. The size of the multilayer vesicles can be controlled by the amount of sheer produced when the polymer mixes with the active ingredients, he said. The typical size of the liquid-crystalline structures is about 5 µm in diameter.
Dow scientists have experimented with encapsulating vitamin C, the skin-repair agent α-hydroxy acid, and the self-tanning dye dihydroxyacetone. Simmonds said the vesicles slowly meter out their contents as they dry out on the skin. This process can provide sustained delivery of vitamins to the skin, he said, noting that it can also reduce the potential of α-hydroxy acids to irritate skin.
Rohm and Haas is looking to harness its acrylate and methacrylate chemistry expertise for use in active-ingredient encapsulation. Paul Reeve, a Rohm and Haas research fellow based at the firm's R&D center outside Nice, France, said many customers have expressed an interest in the technology. The firm could have something to show them a year from now, he said.
A number of smaller companies have developed niches in the active-ingredient-encapsulation market. One such firm is Tagra Biotechnologies, a Netanya, Israel-based firm that has an encapsulation technology based on polymethyl methacrylate. Based on the work of two Russian scientists, the firm got its start nine years ago with the support of Israel's trade ministry, according to Ron Folman, Tagra's director of strategic alliances and investments.
Today, the privately held company employs about 20 people and offers a range of encapsulated ingredients including vitamins, a grape-seed extract with antioxidant properties, the skin elasticity aid evening primrose oil, the antibacterial tea tree oil, and the cooling anti-irritant menthol.
In addition to active ingredients, Tagra encapsulates pigments for customers who incorporate them into sunscreens, said Eran Meiraz, the firm's business development manager. As the 40-µm capsules break open when sunscreens are applied, the pigments provide a visual indication of how well the skin is covered. The red, yellow, and black iron oxide-based encapsulated colors are also useful in cosmetic foundation formulas. And a Nivea aftershave lotion from the German cosmetics maker Biersdorf contains Tagra's encapsulated self-tanning pigments that burst open and provide color to freshly shaved skin, Meiraz said.
Aquea Scientific, a start-up firm that last year introduced easily fractured ceramic capsules used in body washes to "wash on" sun-protection ingredients, said it is now extending its "smart shell" technology to release active ingredients with a pH or friction trigger. Martin S. Flacks, vice president of R&D for the Ventura, Calif., firm, said the sunscreen shells are larger than skin cells because they hold ingredients meant to sit on top of the skin. The new silica-based shells, treated with polymers such as polyquaternium and acrylates, will contain other active ingredients and will be "engineered to be smaller to penetrate the skin."
PRIVATELY HELD Buntech Advanced Compound Technology, a Brazilian maker of cosmetic materials, recently introduced a line called LiquiBeads that is a blend of bentonite and marine- and vegetable-based polymers. The visually compelling beads come in sizes ranging from 0.3 to 0.6 mm in clear, blue, green, red, and purple. General Manager Lars Reibel said the firm can customize beads with specific ingredients or provide them filled with standard materials such as menthol or chamomile, which is often used in rinses for blond hair. The bentonite can act as a mild skin abrasive to smooth rough skin.
Seven-year-old Korean cosmetic ingredient firm BioSpectrum developed its own phosphatidyl choline-derived nanospheres to encapsulate active ingredients. According to a company spokesman, the firm's NLT DioSphere 2.0 contains the wild yam extract diosgenin, which helps to reduce the appearance of skin wrinkles. Other nanospheres in the firm's line hold active ingredients such as ursolic acid, oleanolic acid, and quercetin, which may have anti-inflammatory benefits, the company claims.
With a wealth of delivery systems at hand, Coty's Macchio sees many possibilities ahead. "As I look into the future," he says, "I think we'll have many more active 'smart' molecules with real consumer benefits." Encapsulation technologies, Macchio says, will increasingly have a role in getting those active ingredients to the places where they will do the most good.