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Some New Ideas in Delivery
Before an active ingredient can go to work on age spots,
wrinkles and other cosmetic maladies, it must reach its
target. Here are some of the newest ideas in getting active
materials to the skin.
Tom Branna
Editorial Director
Today’s
cosmetics can help hide age spots, diminish the appearance of
wrinkles and camouflage blemishes and consumers are willing to
pay for all of these disappearing acts. Skin care sales top
$12 billion in the U.S. and are growing 5-6% a year, say
industry sources.
But before they can work their magic,
all of these creams, lotions and gels must deliver their
active components to the skin. As the population in the U.S.,
western Europe and Japan continues to age, cosmetic chemists
are putting an increasing emphasis on developing products that
adhere to the stratum corneum and penetrate into the upper
layers of the skin, to deliver a rich cocktail of peptides,
polysaccharides, enzymes, vitamins and botanicals.
To
effectively deliver these actives to the skin, cosmetic
formulators can choose from a wide array of systems. One of
the newest, and most controversial, of course, are
nanoparticles. In fact, the personal care industry was one of
the first to successfully commercialize nanotechnology with
the introduction of nano-sized sunblocks. But like so many
other scientific breakthroughs before it, nanotechnology must
overcome a host of bad press from nanophobic consumer groups.
That said, even seasoned formulators advise some caution when
formulating with nanoparticles.
“The nanotechnology
that appears to have created controversy in some circles, is
seen as a very promising new technology if handled judiciously
in carefully formulated products,” observed Shyam Gupta,
president of Bioderm Research, Scottsdale, AZ. “These
molecules are so small that some of them can penetrate the
cell wall and enter the living dermal tissue and then the
bloodstream.”
Dr. Gupta noted that this may not be so
desirable for certain materials such as titanium dioxide or
zinc oxide for their benefits in sunblock products, as their
UV-blocking action is best delivered if they remain on top of
the skin and are not absorbed into the deeper layers. The
excessive penetration of titanium into bloodstream may, for
example, cause safety concerns. Nano-dispersed organic
sunscreen agents, such as benzophenones or cinnamate esters,
may also pose similar concerns, according to Dr.
Gupta.
Yet, when used correctly, nanotechnology can
greatly enhance active ingredient delivery. For example,
nano-delivered salicylic acid or benzoyl peroxide for
anti-acne activity may provide potentially incremental
benefits in terms of their increased rate of efficacy, albeit
to a possibly shortened duration.
“As one can see, the
crossover from pharmaceutical research becomes of
critical importance in determining the specific applications
of nanotechnology for topical products,” observed Dr.
Gupta.
Bioderm Research has developed an innovative
nano-diffusion technology using zeolite molecules for the
controlled delivery of certain topical ingredients for a wide
range of products including anti-aging and acne treatments.
The active molecules are loaded into a zeolite cavity. Upon
their application, these molecules are released topically as
the moisture from perspiration enters the zeolite cavity,
which forces those molecules out due to greater affinity of
zeolite for water molecules.
Lessons from Pharma
Dr. Gupta told Happi that
cosmetics research is becoming more dependent than ever on
pharmaceutical delivery systems. He noted that as marketers
desire higher performance products with efficacies approaching
those of pharmaceuticals via topical delivery it is inevitable
that the ingredients with pharmaceuticals-level efficacy but
cosmetics-level regulatory viewpoint will be highly desirable.
“This is not an easy area, as any hint of a drug-type
claim in a cosmetic product could trigger FDA interest,” he
observed. “New delivery systems specifically designed for a
targeted function and utilizing specific ingredients can be of
help.”
Salicylic acid, for example, is a very
popular anti-acne ingredient approved by the FDA in the U.S.
However, it must be formulated at lower pH ranges to provide
its optimal anti-acne efficacy. But lower pH ranges are known
to cause significant skin irritation. Any neutralization of
salicylic acid by common alkali metal or amine bases to a more
skin compatible pH is also known to cause a significant loss
of its activity. An optimized delivery of sal acid would
greatly improve its irritation profile.
Bioderm
Research has recently developed zinc amino acid salicylate
complexes (INCI: zinc glycine salicylate), which provide both
enhanced anti-acne efficacy and more skin compatible pH range
with the added benefit of ease in formulating stable products.
In the same anti-acne area, Bioderm Research has developed a
new “nuclear submarine” delivery system, according to Dr.
Gupta.
“It is well known that bacteria such as
Propionibacterium acnes require a higher level of iron for
their metabolic needs as they multiply at a faster rate than
normal human cells,” he observed.
However, this iron
must be in [Fe3+] state. The [Fe3+], as in Fe(OH)3, is very
insoluble in water. Bacteria utilize molecules called
“Siderophores” to collect [Fe3+] and transport it into their
cells.
A new natural ingredient that spontaneously
binds with the iron part of siderophore forming a
radical-anion has been discovered by Bioderm Research. When
bound in this manner, siderophore enters Propionibacterium
acnes cell and also carries the new radical-anion that is
attached to it. This radical-anion then attaches itself to the
protein of bacterium.
“This binding simply stops the
bacterial multiplication process. It is thus not a true
antimicrobial agent, but a ‘nuclear submarine’ that quietly
enters the bacterial cell wall and deactivates bacterial
metabolic functions that prevent its cellular division,” said
Dr. Gupta. “This new molecule is very resistant to oxidation,
even by benzoyl peroxide. In combination with salicylic acid
or benzoyl peroxide new formulations with enhanced
anti-acne efficacy will be available in the
not-too-distant future.”
For years, liposomal
phospholipids were the delivery system of choice for many
cosmetic formulators. Unfortunately, these materials can
chemically degrade by oxidation and hydrolysis, resulting in
fusion, aggregation, leakage of their internal contents and
other instability problems. As a result, conventional
liposomes are mostly impractical for delivery of protein,
peptides and enzymes.
In contrast,
microencapsulated liposomes are stable and versatile drug
carrier systems that do not have the drawbacks of conventional
liposomes, according to Vispi Kanga, president of Cosmet-Pharm
Consultants, LLC, Cresskill, NJ.
These liposomes are
composed of a wide range of phospholipids in conjunction with
polymers such as alginate, chitosan and gelatins. These
liposomal microcapsules can also be stored in the dry state as
a free-flowing powder.
“This newly developed
pharmaceutical drug delivery technology is likely to be fully
exploited in topical delivery of anti-aging active
ingredients,” predicted Mr. Kanga.
C
Sun care is often one of the first categories to
take advantage of novel delivery systems. | osmetic companies are also
borrowing novel patch technology from the pharmaceutical
industry. Several marketers, including Estée Lauder and Amore
Pacific, have rolled out skin care patches that are based on
transdermal iontopheresis, observed Navin Geria, VP-R&D,
Spa-Dermaceuticals. In the past, pharmaceutical companies have
used this technology to control drug administration through
the skin. Micro-electronic power cells deliver a mild
direct current to the upper layers of the skin, resulting in
super-hydration and a temporary reduction in the appearance of
the wrinkles.
Powders have been used in pharmaceutical
products to deliver many materials to the skin. However, the
walnut shell powder currently used for many products has
uneven edges that can irritate as it exfoliates skin. But now,
researchers at Kanebo have a specially-treated powder that
provides gentle abrasion without irritation. This technology
can be found in Kanebo Silk Peeling Powder.
Raising the Bar on Delivery
Not every novel
delivery system is dispensed from a jar or bottle. Twincraft
Soap, Winooski, VT has developed delivery systems specifically
designed for bar soaps. The technology enables formulators to
add actives such as retinol and salicylic acid directly into a
soap bar.
“Traditional bar soap manufacturing requires
high temperature and pressure, both of which destroy
liposome-based delivery systems,” explained Joe Candido,
VP-sales, Twincraft. “We’ve developed special soap bases in a
temperature-resistant powder, reduced the temperature in our
manufacturing environment and modified our extruders so they
don’t damage the delivery system.”
The technology
enables salicylic acid and retinol to get into the matrix to
exfoliate and repair skin, reduce wrinkles and break up
comedones. Now, Twincraft has created botanicals that can be
added into anti-aging or anti-acne soaps to act as
anti-inflammatories. To boost moisturizing properties, the
company is testing a compound blend of humectants.
Also
in development are self-tanning solutions and a UV protection
product that adheres to skin and time-releases active
ingredients such as octyl methoxy cinnamate.
“OMC
breaks down with time,” explained Mr. Candido. “Our system
adheres to skin and releases the active over time.”
As
Twincraft prepares to enter the wash-on UV protection segment,
it faces stiff competition from Aquea Scientific. The Ventura,
CA-based company already markets Wash-On, a patented
technology to encapsulate active ingredients into micron sized
particles, which are then positively charged. As a result,
encapsulated active ingredients are attracted to negatively
charged skin and hair. Active ingredients delivered
through the system will remain attracted to the skin and hair
throughout the day, even after patting dry.
An Array of Applications
The technology can
already be found in products such as 24-7 Ice Shield Facial
Cleanser, which is utilizing the delivery system to
incorporate sunscreen with a SPF of 15. In addition to sun
protection, the Wash-On system can potentially deliver any
active ingredient, including anti-aging, anti-acne,
moisturization and OTC pharmaceuticals, among others. Company
executives insist they’ve created a third category in personal
care.
“Before there was only wash-off and leave-on.
Aquea has discovered the wash-on category to deliver active
ingredients and make them stick to the skin even in the
presence of surfactants,” explained Dave Compton, president of
Aquea Scientific. “This isn’t super glue, we believe it’s the
best way right now of attracting actives to skin the presence
of surfactants.”
The process wraps active materials in
a silica wrap that forms a shell and takes on the character of
the active material, according to Martin Flacks, head of
R&D. The material is then placed in a polymer matrix which
imparts a strong cationic charge to the outside of the shell
and make it positively charged. Thus, any active will be
attracted to negatively-charged skin. The delivery system
ensures that the actives don’t penetrate too deeply into
skin.
“In traditional formulas, OMC can penetrate 50
microns into the stratum corneum,” explained Mr. Flacks. “But
when a product is wrapped in our technology there is a lot of
diffusion, penetration is just 10-13 microns.
“So if
you put an active ingredient like sunscreen in our system, it
stays on the surface and increases the safety of the
product.”
Although Aquea Scientific’s initial emphasis
is on sun care, company executives insist the Wash On
technology has applications in a broad range of anti-aging,
skin lightening, even insect repelling
products.
From bar soaps to skin patches to
nanospheres, marketers realize that when it comes to
formulating effective skin care products, more often than not,
it’s all in the delivery!
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