Creating a hostile environment for bacteria and other microbes is the essence of product preservation. At the same time, preservative manufacturers must successfully navigate a hostile world of regulatory issues and approval processes, escalating product development costs and growing consumer demand for all-natural systems. All of these issues make the preservative universe more complex than ever, even as the world gets smaller for many global manufacturers of household and personal care products.
"Most customers are looking for a globally-approved preservative for their global formulations," noted Ben Blinder of TRI-K Industries. "Ten or 12 years ago, customers had formulas for each region, but now they are developing global formulations."
"The ongoing trend toward global formulations continues to drive the need for globally approved preservatives," agreed Joan Hoffmeier of Rohm and Haas. She noted that Kathon CG continues to be the preservative of choice for many formulators of hair care products because of its global approval status as well as its low use levels, broad spectrum activity and excellent safety profile.
Additionally, the popularity and expansion of UVA absorbers such as avobenzone in skin and sun care products create opportunities for Rohm and Haas' Neolone 950. "Unlike some competing products, Neolone 950 is compatible with avobenzone," said Ms. Hoffmeier. "This fact, coupled with its excellent efficacy and safety profile, is driving its use in the marketplace."
Industry experts agree that shampoos and shower gels are relatively easy to preserve, especially if a quaternary ammonium or amphoteric surfactant has been used in the formulation. That's because such quaternary and amphoteric surfactants also have preservation properties, especially against bacteria, noted Shyam Gupta, Arizona Natural Resources. However, formulating effective preservative systems for eye creams or anti-aging products is more difficult.
Challenges of Preservation
"Most eye creams, eye serums and anti-aging creams contain ingredients such as proteins, amino acids, peptides, carbohydrates and natural oils that are strong promoters of bacterial and fungal growth," noted Dr. Gupta. "The preservative system for such formulations should be effective against both bacteria and fungi and also non-irritating to skin."
He told Happi that any time a great number of ingredients that can promote bacterial and fungal growth are combined in a cosmetic product, the selection of a preservative system requires meeting six criteria:
. efficacy in controlling bacterial and fungal growth;
. low or no skin irritation;
. use level at less than 0.5% (preferably at less than 0.1%);
. cost effectiveness;
. INCI name friendly and
. regulatory approval status.
"If an ingredient has an unfriendly INCI name, then consumers may avoid it even if that ingredient is a high performer," explained Dr. Gupta. "For example: iodopropynyl butylcarbamate. What a tongue-twisting INCI name! But, it really works to control fungi at very low use levels. Another problem: it is not yet approved for use in Japan."
Mike Hooper of Body Blue, a Canadian contract manufacturer, noted that preserving eye creams can pose a challenge to formulators. "The skin around the eyes is thinner than that found on the rest of the face; therefore, it is delicate and sensitive to both preservatives and microorganisms," Mr. Hooper said. "Great care must be taken to utilize mild, effective preservatives in order to prevent irritation or infection."
Other formulas such as the microemulsion gels common in hair pomade can be difficult to develop for two reasons. "First, most preservatives are unstable at the high filling temperatures required for such formulas," he said. "Second, although parabens are stable at high temperature, they can be inactivated in the presence of high HLB nonionic surfactants as they are captured within the micelles."
|Careful consideration of the preservative system is required when it comes to products that are formulated for the delicate skin around the eyes.|
According to Pat Lutz of Lonza, the increased use of natural ingredients, with corresponding additional bioloading, continues to impact preservative choice and concentration.
Linda Sedlewicz, Schülke & Mayr, agreed that the move toward natural, as well as cosmeceutical, products is still strong globally. She added that Euxyl K 700 is a globally-approved (including Japan) preservative blend that works extremely well in these systems. The components (phenoxyethanol, potassium sorbate, benzyl alcohol and tocopherol) are recognized by the consumer as safe and effective. For more difficult-to preserve systems, SensivaSC 50 (ethylhexylglycerin) has proven to be an effective preservative enhancer. It is also globally approved (including Japan) and boosts the activity of preservatives in formulas that require a little extra strength.
"In the sun care market, formulators are increasing SPF levels for maximum protection against both UVA and UVB rays," noted Cecilia McGough of Clariant. "The UVA and UVB filters are materials that usually cause some reduction in the performance of preservatives. Also, the on-going trend is toward natural raw materials, but in most cases, they are a perfect food source for the microbes."
Several suppliers also noted that growing demand for wipe products has created another set of challenges for preservative systems. The combination of the liquid solution and the impact of the fabric substrate has increased the difficulty in preserving these types of products.
"Wet wipes are particularly difficult to preserve because the wipe material, whether woven or nonwoven, can be both the source of contamination and an excellent substrate for organisms to grow on," observed Ms. Sedlewicz of Schülke & Mayr.
Two Schülke & Mayr products, Euxyl K 600 and Euxyl K 702, work particularly well in cosmetic wet wipes. Euxyl K 702 is a synergistic phenoxyethanol/organic acid blend that is effective at relatively low use levels in products that are pH 5.5 or below. For products with higher pH, Euxyl K 600 is a patent-pending, color-stable, liquid iodopropynyl butylcarbamate blend that is extremely effective against fungal contamination.
Specific ingredients, too, can make a difference in product preservation, observed Ms. McGough. She told Happi that the use of silicone emulsions in skin care and hair care makes it critical for cosmetic chemists to evaluate many factors before choosing a preservative system.
A Regulatory Update
As suppliers grapple with the latest preservation issues caused by new formulation trends, they are also forced to wrestle with regulatory issues which never seem to go away. Japan remains a very difficult market to get product approval; in fact, the Japanese government has not added any new preservatives to its positive list since April, 2001. Moreover, a lack of global harmonization can cause headaches for suppliers.
On the subject of regulations, Ms. McGough described 2002-2003 as a complex year, as countries such as Canada and Australia have drafted new proposals that will impact both raw material and cosmetic manufacturers. Japanese reluctance to expand its preservative list is having an impact on the market, according to Clariant's Rudi Itoe.
"This has led many preservative suppliers to develop blend formulations with current actives with already globally-approved status," he noted. "Also, with very few formaldehyde donor preservatives approved in Japan, the market is now becoming increasing obsessed with formaldehyde-free preservatives/blends."
Ms. Hoffmeier noted that regulations are still challenging, costly and slow. She pointed out that within the household sector, where state registrations are required in addition to EPA approvals, the year-over-year cost of getting and maintaining state registrations on preservatives continues to escalate.
|With more personal care and household products boasting natural ingredients, such as grapeseed, some companies expect their preservative systems to be natural too.|
If that weren't enough, Linda Sedlewicz of Schülke & Mayr told Happi that preservative suppliers are feeling additional pressure from toxicology and dermatology communities. "There is increasing discussion in Europe and the U.S. about certain chemistries that are among the most common preservatives for cosmetic formulations," she noted. "This further limits the materials that are available to be used and makes adequately preserving a product more difficult. Schülke & Mayr's experience in developing optimized blends of preservatives puts us in an excellent position to meet this challenge."
Pressure from non-regulatory groups continues to grow, agreed Mr. Cappabianca of Lonza. "We have found that often, it is not regulations that impact preservative choice, but consumer perception."
He explained that publications, especially in Europe, tend to criticize typical personal care ingredients without any scientific justification. As a result, there is frequent unfounded concern and movement away from established systems that are safe and effective.
Although developing a new preservative system can be a costly, time-consuming endeavor, suppliers continue to expand operations throughout the world. Clariant, for example, has upgraded its methylparaben (Nipagin M) facility in South Wales to increase production capacity. And, Ms. Mc-Gough noted, as part of the company's continued commitment to provide customers with the optimum preservative system for their formulation, Clariant R&D, with laboratories throughout the world, is working on several different technical support projects and new product development.
Lonza has expanded preservative production capability in Europe to enhance its ability to quickly supply and service customers throughout Europe and points East. In Asia, although its DMDM hydantoin is now technically approved in Japan for personal care applications, Lonza continues to work with Japanese authorities to remove end-product warning labels.
"Additionally, Lonza is fully supporting personal care approval of IPBC in Japan," said Mr. Cappabianca. "Both of these key chemistries are growing in popularity in household and industrial applications in Japan, indicating customer acceptance and overall effectiveness of these materials in various formulations."
Jeen International's primary focus is on other core platforms of specialty polymers. However, Chris Tarletsky said Jeen has found new business from preservative blend programs. "This approach is becoming even more popular in the international arena due to increased ability towards inventory management," noted Mr. Tarletsky. "By blending some very common preservatives, the customer in essence is now managing a single product."
At the same time, he told Happi that although the blended approach is not yet fully promoted within the European market, "the customer's ability to effectively manage the supply chain is greater there, than perhaps in Asia."
Lipo Chemicals is launching a new line of personal care preservatives called Liposerve. The four-item line has applications in skin care, hair care, color cosmetics and cleansing preparations. In other news, the company recently added capacity in its Paterson, NJ and Vandalia, OH plants.
Lonza executives say their company is meeting demand for natural preservation with the introduction of Natrulon, which it bills as the first truly effective, broad-spectrum, naturally-derived preservative system to address consumer-preference for complete, or near-complete natural formulations.
"Customers have indicated a strong need for a natural preservative system to match other formulation ingredients," noted Mr. Lutz. "We have been hard at work to address this need."
If formulating a natural preservative weren't difficult enough, many natural ingredients pose problems of their own. Mr. Hooper of Body Blue noted that the increasing use of "certified organic" materials may present some issues in the future. "These materials have an increased potential for being contaminated initially and are more susceptible to bacterial attack and degradation within the final formula," observed Mr. Hooper. "It will be difficult to overcome these challenges while avoiding the use of synthetic preservatives."
Mr. Blinder of TRI-K pointed out that more companies are researching non-preservative preservative systems, such as botanical extracts with preservative attributes. "In the past, researchers didn't look too closely at botanicals, now they're trying to isolate specific components that may have preservative attributes," he said.
|Personal care wipes present unique challenges to preservative manufacturers.|
But not every new development in preservation is focused on natural ingredients. Geogard was introduced by Lonza more than a year ago and platform extensions will be launched throughout the year, according to company executives.
"The initial launch and customer response has been outstanding. Customers like the global acceptance of Geogard; it enables them to use one preservative system worldwide for their formulations," said Mr. Cappabianca. "Customers have also found Geogard an effective alternative to paraben-based products."
For household product applications, in mid-2002, Lonza introduced Dantoserve, a patented, safe combination of hydantoin and benzisothiazolinone chemistries that Lonza executives say provide unique user benefits.
In Europe, Lonza recently introduced Benzocil for household and industrial applications. According to Lonza's Muriel Girault, this benzisothiazolinone-based product line provides another key active ingredient in Lonza's already extensive portfolio.
TRI-K's expertise is in the area of custom-blending. Mr. Blinder said the company is working on new blends and that the company may make an announcement in this area sometime during the summer.
Jerry Konst of Dow Biocides, said his company is promoting Dowicil QK-20 as an option for the personal care industry for uses in manufacturing and processing, not in the final product as a good option to clean up raw materials, wash water, and equipment. In other Dow developments, debottlenecking is ongoing at nearly all manufacturing sites to increase preservative production capacities.
Nearly all industry experts agree that in the future, consumers will expect formulations to provide high-performance benefits, which will necessitate the use of a far greater number of new, innovative ingredients compared to the formulations of today.
"The more complex a formulation is, the more challenging it will become to preserve it," said Dr. Gupta. "As the formulations contain increasing amounts of skin nutritive ingredients, some ingredients that are nutritive to human skin may also provide nutritive benefits to bacteria and fungi. The 'natural' preservatives, such as sorbitol and sodium benzoate, may not be adequate for such formulations of the future."
Furthermore, Dr. Gupta said the industry needs a preservative that is made from natural ingredients, is effective at low use levels at both low and high pH conditions (although no preservation may be necessary for the products that have a pH lower than 2.5 or higher than 12.0), is non-irritating to skin, and is cost effective.
Although there is no product currently on the market that meets all of Dr. Gupta's requirements, it's a safe bet that preservative suppliers are back in the lab, hard at work developing the ultimate in product preservation.
Looking for a preservative system? A list of them can be found on p. 108 in the print version of Happi.