Preservative Update

November 10, 2005

Have a preservation problem? Industry suppliers provide a wide range of solutions.

The products are more complex, the regulatory situation is still cloudy in some parts of the world and the approval process remains expensive and lengthy. Still, preservative suppliers say that they have solutions for many of the preservation problems that affect household and personal care products. At the same time, suppliers are launching a variety of new products to help marketers overcome many hurdles.

Today's novel product forms can create preservation problems, according to industry experts. For example, some of the newest powders and silicone-based creams have low water content. Others, such as oil-based and anhydrous creams, have no water, and still others have water in the internal phase. Formulating a preservative into these systems can be difficult.

According to Mary Chervenak of Dow Biocides, sometimes the preservative in a low- and no-water system simply will not go where it might be needed and therefore, the preservation of these products must be carefully evaluated.

"A product that contains very little water may not support bacterial growth; the environment may be too hostile," noted Ms. Chervenak. "No one is really sure yet if a low-water or no-water product really needs a preservative and, if the product does need a preservative, how the effectiveness of the preservative should be evaluated. Preservative assessment and method evaluation are, at this moment, under consideration."

Water solubility and incompatibilities with other components are a concern in choosing a preservative system. Cecilia McGough of Clariant agreed that silicones in water emulsions is a growing product area. Formulations using these emulsions have a silicone/water barrier, which some, using the traditional means of incorporation, are unable to penetrate.

Linda Sedlewicz of Schülke & Mayr said that silicone-based emulsions not only pose the question of what preservative to use, but also how to best incorporate that preservative and how to test for adequacy of protection.

"If a preservative is added to the water phase and a contaminant is introduced into the product after emulsification, is that contamination ever actually in contact with the preservative or is the contamination maintained in the silicone phase as an additional phase?" asked Ms. Sedlewicz. "Or, if the preservative is added to the product after emulsification, do we have four phases: water, silicone, preservative and contaminant?"

The other issue the industry is trying to figure out is whether or not contaminants can thrive in the silicone phase. If not, "why do we even need a preservative?" she theorized.

Carl Cappabianca of Lonza agreed that reducing the amount of water in a formulation can reduce the amount of preservative needed, but he said that this does not appear to be a strong trend in the market. Rather, more companies are creating products with higher water content to accommodate a wider range of raw materials, including naturals. As a result, higher water content creates a greater need and higher level of preservatives.

"Overall, although some formulators are focusing more on water reduction, the majority do not formulate specifically with preservative reduction in mind," said Mr. Cappabianca. "Rather, they tend to concentrate more on end-user benefits of the formulation."

Larry Smith of International Sourcing Inc. told Happi that even if less water is used in a formula, it would not result in a lower level of preservative because of the need to protect other materials such as proteins.

The increased use of natural ingredients is putting greater pressure on preservative systems due to this improved environment for microbial contamination, noted Joan Hoffmeier of Rohm and Haas. "Another issue is that avobenzone is becoming more widely used in sun care formulations, and it is difficult to find compatible preservatives for this SPF active," she said. "We have done significant formulation testing to show that Neolone 950 is compatible with avobenzone."

What's with Wipes?
As a result of an increasingly sophisticated consumer demand for more convenient and effective products, the wipes market is witnessing an explosion of new and innovative products, noted Jim McNairney of Avecia. "Everyday items ranging from household cleaning wipes, through floor cloths to pre-moistened wipes have been introduced or revamped. Major global corporations such as Procter & Gamble and Kimberley-Clark have introduced new cleansing cloths and wipes impregnated with chemicals designed to improve their functionality and effectiveness," he said.

But formulating a properly preserved wipe can be difficult, according to some industry suppliers. That's because wipes have two distinct phases that must be protected from microbial contamination-the solution and the substrate. According to Ms. Sedlewicz, the substrate is typically not sterile and can support microbial growth as well as introduce microbes into the system. Therefore, there must be enough preservative in the solution to protect not only the solution itself, but the wipe as well.

"In addition, wipes often are not uniformly saturated with solution," noted Ms. Sedlewicz. "This means that some portions of the wipe contain more preservative and some less. This all must be carefully balanced with the fact that too much preservative can be potentially irritating."

According to Dr. McNairney, Avecia offers manufacturers wipes that respond to changing consumer requirements in three individual product types-Vantocil, Cosmocil and Reputex antimicrobials. These products deliver distinct advantages in wet, fine quality and dry wipes respectively, giving finished product differentiation and modern consumer appeal. Avecia's antimicrobials deliver the key benefits of preservation, deodorizing effects and odor control, which are required by wipe manufacturers.

Regardless of the finished product form, when it comes to preserving household and personal care products, in many cases the entire formulation is coming under scrutiny. Formulators are paying greater attention to the preservation requirements of a formulation, while at the same time, there is more of an attempt to formulate in order to minimize the concentration of preservatives, noted Tammy Gafney of Ondeo Nalco. "More attention is being paid to adding ingredients, such as phenoxyethanol, EDTA and glycols, which either have inherent antimicrobial activity, or can boost the performance of a preservative."

The use of preservative blends is a trend that began several years ago and remains strong, according to Tom Shoenberg of McIntyre. He noted that blends are typically a combination of an effective antibacterial preservative with an effective anti-fungal preservative. Preferably, the blends are easy to handle liquids that disperse readily in room temperature water, thus reducing the need to heat the product.

Natural Preservation: Yes or No?
Perhaps no other issue is more controversial than natural preservation. Years ago, many preservative suppliers scoffed at the notion of a natural preservative. They insisted that products such as grapefruit seed extract could not provide adequate protection from microbial growth. In recent years, however, more industry observers have become less hostile to the concept of natural preservation, and a few of them are aggressively looking for answers.
For instance, Mr. Cappabianca of Lonza told Happi that the industry is closer to finding an answer to natural preservation, but he insisted that truly efficacious and cost-effective natural preservative alternatives remain several years away.

"We continue to work on new approaches to preservation and the development of naturally-derived preservative ingredients is one of those approaches," said Mr. Cappabianca. "It is almost a contradiction in terms-natural and preservation-and there are regulatory, compatibility, stability and other constraints. However, the concept certainly has market value, particularly for formulators focused on products containing primarily natural ingredients."

Other industry suppliers insist the obstacles to natural preservation remain firmly in place when it comes to water-based formulas. "A single natural preservative just isn't practical," said Ms. Chervenak. "Although some organic oils and other natural products have antimicrobial activity, their biocidal capabilities are limited and they usually cannot withstand the continuous reinoculation that most personal care products must endure. Most personal care formulations use preservatives in combination to combat the introduction and reintroduction of bacteria."

Ms. Hoffmeier of Rohm and Haas noted that natural preservatives are generally multi-component systems that are difficult to characterize from a performance standpoint and difficult to standardize in order to gain regulatory approval.

A Tough Situation in Japan
Several years ago, the Japanese government changed the approval process for cosmetic ingredients, moving from a positive list to a negative list. At first glance, the move appeared to be a victory for the personal care industry. But now, several years later, industry experts note that Japan is still the most difficult market for cosmetics manufacturers and suppliers to navigate.

"They didn't deregulate cosmetics-they substituted a complicated system for one that is almost as complicated," noted David Steinberg, president of Steinberg & Associates Inc., Plainsboro, N.J. "Now, the preservative list is transparent, but the Japanese haven't approved any new preservatives."

Mr. Steinberg noted that Japan did approve two preservatives in 2001, DMDM hydantoin and imidazolidinyl urea, but only for use in rinse-off products. Moreover, products that contain these preservatives must carry a warning label that reads: "Should not be used by infants or by people who are hypersensitive to formaldehyde." Japan has also changed the status of parabens to include the sodium salts.

Elsewhere, Mr. Steinberg said that preservative regulations have improved in Europe during the past year, as regulators moved all provisionally-allowed preservatives (B list) on to the A list. "They cleaned it up," he said.

More good news for preservative suppliers is the fact that most countries in Latin America follow European Union standards, so companies will not have to tinker too much as they move products from Europe to Latin America and vice versa. So how can a company develop a truly global formulation? Mr. Steinberg suggested formulators look at the most restrictive market-in this case, Japan-and formulate to meet those requirements.

Lonza did just that when it developed new Geogard. The product contains preservative ingredients that are already acceptable in Japan. "These products provide global solutions now," said Mr. Cappabianca. "Regarding new preservatives in Japan, it is still too early to determine if the approval process will actually be accelerated based on recent regulatory changes."

What's New from Suppliers
Lonza isn't the only preservative manufacturer launching new products. Ondeo-Nalco recently introduced Merguard X-18, a liquid blend of methyldibromo glutaronitrile and 2-bromo-2-nitropropane-1,3-diol in dipropylene glycol. "With the industry trending away from the use of secondary amines in formulations, Merguard X-18 will become a popular preservative due to its cost efficacy," insisted Ms. Gaffney.

Even shampoos are more complex these days. New Avon Advance Techniques Element Defense contains antioxidants, moisturizers and sunscreens.
The most recent addition to the Schülke & Mayr line of preservative blends is Euxyl K700. According to Ms. Sedlewicz, this unique, organic acid-based liquid system is approved for use in Japan and is particularly effective in treatment products and other low pH systems.

Late last year, Clariant began producing methylparaben (Nipagin M) at a new plant. New and updated microbiological laboratories were established in Mount Holly, NC and in Leeds, UK. Clariant is building new R&D facilities to focus on new and innovative preservative systems for the cosmetic and personal care market, said Ms. McGough.

Avecia's Proxel GXL antimicrobial has recently been cleared by the U.S. EPA for sales as a preservative in the laundry additive sector. Dr. McNairney said Proxel GXL antimicrobial is already a well-established sales line in the U.S. and Europe as a preservative in a number of household product sectors. The move will enable Avecia to promote the product in the US as a benefit in liquid laundry detergents, fabric softeners and stain removers.

Of course, the integration of three companies that marketed biocides, Dow, Angus and Union Carbide, has resulted in a greatly expanded line of personal care products for The Dow Chemical Company, according to Ms. Chervenak.

In the household and industrial product market, Lonza will be launching several new EPA registered preservatives by mid-2002.

Rohm and Haas' Neolone 950 preservative is being globally developed for use in personal care applications. This new preservative will complement the company's Kathon CG preservative by offering an alternative for leave-on applications such as skin care and sun care formulations, whereas Kathon CG had predominately been used in rinse-off applications.

"Neolone 950 preservative will offer our customers an excellent alternative to formaldehyde-releasers in a number of personal care applications," said Ms. Hoffmeier. "It is compatible with a wide range of personal care raw materials including surfactants and emulsifiers, zinc pyrithione and avobenzone." Global registration is expected shortly for Neolone 950.

Neolone M-10 preservative has been EPA-approved for preservation of household and institutional products, including hard surfaces cleaners, surfactants and liquid detergents. According to Carl Shervin of Rohm and Haas, the bactericide offers excellent compatibility in high pH systems and can be readily blended with a fungicide for full spectrum protection.
Global registration is expected shortly for Neolone M-10.

These are just some of the examples of the newest preservation solutions available from industry suppliers. As product formulas become more complex, personal care and household product manufacturers will continue to seek solutions to their preservation problems from industry suppliers.

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