Formulating Hydroalcoholic Gels with Carbopol Technical ... - Lubrizol

TECHNICAL DATA SHEET
TDS-255
Edition: September 3, 2009
Previous Editions: December, 1999 / March 25, 2004 / May 12, 2008
Original Date: May, 1998
Formulating Hydroalcoholic Gels with
Carbopol ® Polymers
Use of Hand Sanitizing Gels to Reduce Germ
Transmission
Hydroalcoholic hand sanitizing gels have found
increasing use by consumers and institutional
facilities. These gels have gained popularity due to
their ability to instantly kill germs and bacteria on the
hands without the use of soap and water. These gels
can be formulated to provide pleasant sensory and
good conditioning on the hands even while providing
effective disinfecting performance.
Carbopol ® polymers and other Lubrizol Advanced
Materials’ rheology modifiers are the preferred
polymers to provide cost-effective and aesthetically
pleasing ingredients to thicken and stabilize
hydroalcoholic gels.
Background:
Viruses and bacteria such as Staphylococcus, E.coli,
Salmonella, and influenza can cause illnesses and
are typically transmitted via person-to-person
contact, as well as object to person contact. A
simple handshake, touching of a doorknob, pushing
elevator buttons, answering a telephone and
contacting other common objects in public areas can
all be sources of germs. Whether travelling by
airplane, bus or train, as well as frequenting public
places in general, there is potential exposure to an
array of harmful and potential infectious bacteria and
viruses. These environments represent an
opportunity for rapid spread of harmful microbes.
The probability of transmission increases when
personal hygiene or hand washing habits are
inadequate.
Washing hands with water and soap is an
effective way to remove visible dirt and reduce
the number of germs on your hands. However, it
is not always feasible or practical to wash your
hands as often as desired. The use of hand
sanitizing gels significantly reduces the potential
for germ transmission as well as the risks of
contamination. These gels can be also used to
supplement disinfection of the hands after normal
washing with soap and water for additional
protection.
Formulating a Hydroalcoholic Hand Sanitizing
Gel
Hydroalcoholic gels basically contain four major
ingredients: alcohol, water, rheology modifier and
neutralizer. The effectiveness of the sanitizer
using alcohol depends on the amount and type of
alcohol. The FDA proposed monograph considers
the effective concentrations as follows:
• Ethanol at 60-95 v/v%
• Isopropanol at 70-91.3 v/v%.
Alcohol can destroy the lipid containing cell
membrane of bacteria and fungus and denatures
proteins and enzymes inside bacteria and fungus.
Alcohol kills bacteria and fungus almost instantly
upon contact.
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Lubrizol Advanced Materials’ rheology modifiers are
efficient ingredients to provide thickening,
stabilization and suspension of these types of
formulations. Carbopol polymers are the preferred
polymers to provide cost effective and aesthetically
pleasing hand sanitizing gels. The use of Carbopol
polymers will create thick clear gels that will prevent
dripping and will maximize contact of alcohol on the
skin for optimum performance.
Benefits
• Quickly kills bacteria when water is not available.
• Quickly evaporates on application requiring no
need for rinsing or drying of the hands.
• Consumer convenience over ordinary hand
washing with soap and water.
• Emollients, botanical extracts, moisturizers and
fragrances can all be incorporated and are
compatible -- thus helping to provide additional
functional benefits such as conditioning.
TDS-255
Formulating Hydroalcoholic Gels with Carbopol ® Polymers
Page 2 of 6
Polymer Selection
Although all Carbopol polymers can thicken
hydroalcoholic systems, several grades offer
advantages such as higher clarity, better
efficiency, ease of handling and better overall
aesthetics for hand sanitizing gels. All three of our
Carbopol Ultrez polymers are good rheology
modifiers for these gels. A typical hand sanitizing
gel contains less than 40 wt% deionized water.
Due to this constraint, the low dispersion viscosity,
as well as the processing ease, makes the
Carbopol Ultrez polymers well-suited for these
types of formulations as compared to the more
traditional polymer grades. The following table will
assist in polymer selection.
Carbopol ® Polymer Ultrez 10 Ultrez 21 Ultrez 20 980 940
HSG Viscosity*, >0.2 wt% ��� ��� �� ��� ��
Clarity �� �� ��� � �
Electrolyte Tolerance � �� ��� � �
Smoothness after use ��� ��� ��� �� ��
Ease of dispersion ��� ��� ��� � �
Balling or Pilling** � �� ��� � ��
��� Preferred � Lower performance
*The HSG Viscosity references the formulation viscosity of the Hand Sanitizing Gel shown in table below
**The more checks the less pilling of system occurs
Screening Formulation for Carbopol Polymer Comparison
Use Level of Carbopol ® Polymer 0.1 wt% 0.2 wt% 0.3 wt% 0.4 wt% 0.5 wt%
Deionized Water (wt%) 39.8 39.6 39.4 39.2 39.0
Ethanol (wt%) 60.0 60.0 60.0 60.0 60.0
TEA (wt%) 0.1 0.2 0.3 0.4 0.5

Clarity Results: %Transmittance at 420 nm
Clarity, %T
100
90
80
70
60
50
40
30
20
10
0
TDS-255
Formulating Hydroalcoholic Gels with Carbopol ® Polymers
Page 3 of 6
Clarity of Hand Sanitizing Gels
0.10% 0.30% 0.50%
Polymer Concentration, wt% TS
Viscosity Results: Brookfield RVT, 20 rpm @ 25°C
Viscosity, mPa•s
25,000
20,000
15,000
10,000
5,000
0
Viscosity of Hand Sanitizing Gels
0.10% 0.30% 0.50%
Polymer Concentration, wt% TS
Carbopol® 940 Polymer
Carbopol® 980 Polymer
Carbopol® Ultrez 10
Polymer
Carbopol® Ultrez 21
Polymer
Carbopol® Ultrez 20
Polymer
Carbopol® 940 Polymer
Carbopol® 980 Polymer
Carbopol® Ultrez 10
Polymer
Carbopol® Ultrez 21
Polymer
Carbopol® Ultrez 20
Polymer

Neutralization of Carbopol Polymers in Hand
Sanitizing Gels
The key to formulating a hydroalcoholic gel with
Carbopol polymers is choosing the correct
neutralizing agent. Many neutralizing agents
commonly used to neutralize Carbopol polymers in
aqueous systems do not work in hydroalcoholic
TDS-255
Formulating Hydroalcoholic Gels with Carbopol ® Polymers
Page 4 of 6
systems. There are amine solubility limitations with
high alcohol, low water containing systems. The
solubility of the Carbopol polymer salt changes as the
alcohol level is increased making the choice of
neutralizing agents important. Different choices are
provided as a guideline for the different alcohol type
and level.
Neutralizing Agent Versus Alcohol Level
Maximum
Alcohol Neutralization Ratio*
Trade Name INCI Name Manufacturer Level Base/ Carbopol ® Polymer
NaOH (18%) Sodium Hydroxide 20% 2.3/1.0
KOH (18%)
Potassium
Hydroxide
30% 2.7/1.0
TEA (99%) Triethanolamine 60% 1.5/1.0
Tris Amino (40%)** Tromethamine Angus / Dow 60% 3.3/1.0
AMP ® Ultra PC2000
Neutrol ® TE
Aminomethyl
Propanol
Tetrahydroxypropyl
Ethylenediamine
Angus / Dow 80% 0.9/1.0
BASF
90% 2.3/1.0
Triisopropanolamine Triisopropanolamine Dow 90% 1.5/1.0
* Ratio values indicated above are for mucilages. For the 60% hydroalcoholic gel, divide the base ratio amount by 1.25
**NOTE: The 40% solution should be made from the Tris Amino crystal provided by the manufacturer. We do not recommend using
the predispersed solution produced by the manufacturer due to its high impurity content
Check your local regulations while selecting the appropriate neutralizing amine since there are often specific
guidelines on the type of amine and impurity level in the amine for these types of formulations.
Modification and Formula Enhancements for Hydroalcoholic Gels
Common Formulation additives for Hand Sanitizing Gels
Water soluble emollients
Emollients
Fragrance
Carbopol ® polymers
Rheology modifier
Alcohol
Disinfecting agent
Specialty Silicones
Botanical Actives

Formulation and Manufacturing Guidelines
• Typical hand sanitizing gels contain less that 40
wt% water. Due to this formulation constraint, a
common concern is how to effectively incorporate
the Carbopol polymer. The general methods are
outlined as follows, dependent on your choice of
polymer:
Direct Method: The direct method is the traditional
method for dispersing Carbopol polymers.
Carbopol Ultrez Polymers: This method is made
easy with Carbopol Ultrez polymers since you simply
sprinkle the polymer on the surface of the water.
Allow the polymer to self wet and then begin
agitation. The general procedure is described as
follows:
1. Disperse the polymer into the water. Mix until
smooth to insure a lump free dispersion is
obtained.
2. Slowly add the alcohol with agitation and mix until
homogeneous.
3. Add emollients if desired. Keep in mind that the
order of addition may be critical to maintain
product clarity. See “Adding Emollients” for
further information.
4. Add the appropriate neutralizing agent with gentle
sweeping agitation and mix until smooth.
NOTE: If production equipment constraints require
the water and alcohol to be combined before the
dispersion of polymer, the Carbopol Ultrez polymers
must be dispersed like a traditional polymer. The
Carbopol Ultrez grade polymers will not self wet in a
solution of water and alcohol.
Carbopol Traditional Grade Polymers: These
polymers can be dispersed in either the water or
alcohol/water mixture. The polymer will swell more
slowly when added to the alcohol/water mixture, so
care must be taken to avoid the clumping and
skinning of the polymer during the dispersion
process.
1. Carefully disperse the polymer in the water or
water/alcohol mixture with good agitation. High
mixing speeds are generally preferred as it
prevents agglomeration of the polymer on the
surface of the water. Mix until the polymer is
hydrated and the dispersion is smooth and free of
lumps.
TDS-255
Formulating Hydroalcoholic Gels with Carbopol ® Polymers
Page 5 of 6
2. Add the alcohol with slow mixing to de-aerate the
formulation if it was not included in Step 1.
3. Add emollients if desired. Keep in mind that the
order of addition may be critical to maintain
product clarity. See “Adding Emollients” for
further information.
4. Add the appropriate neutralizing agent with gentle
sweeping agitation and mix until smooth.
• Water Source: Use deionized water. Carbopol
polymers are sensitive to hard water ions,
therefore, the clarity and viscosity may be
negatively affected if regular tap water is used. If
deionized water is unavailable, add a chelating
agent such as tetrasodium EDTA at a level of
about 0.05-0.10% (wt/wt%).
• Adding Emollients: Several commercially
available emollients can be added to the hand
sanitizing gel to compensate for removal of oils
on the hands by the alcohol. The following watersoluble
emollients can be added directly to the
water and polymer dispersion or just before
neutralization. The use of these emollients from
0.3-0.5 wt% addition will not impact the final
product clarity.
Trade Name INCI Name
Glucam E-20 Humectant Methyl Gluceth-20
Glucam E-10 Humectant Methyl Gluceth-10
SilSense Copolyol-1 Silicone PEG-33 and PEG-8
Dimethicone and PEG-14
SilSense SW-12 Silicone Ester Dimethicone PEG-7 Cocoate
Hydramol PGPL Emollient PEG/PPG-8/3 Laurate
Hydramol PGDS Emollient PEG-90 Diisostearate
The Hydramol emollients can be added at use
levels from 0.5-3.0 wt% and still maintain good clarity
in the system.
The use of other emollients may impact the final
product clarity depending on the solubility profile of
that particular emollient. Other emollients, such as
isopropyl myristate, may need to be added to the
alcohol and the water/polymer dispersion added to
the alcohol/emollient phase to maintain final product
clarity.

Clarity (% Transmission @ 420 nm)
All polymers suggested for this application have
excellent clarity in hydroalcoholic systems. Clarity
can be affected by many factors including dispersion
techniques, water source, emollient content,
formulation pH, type and level of fragrance and/or
dye addition. Hydroalcoholic gels made with
Carbopol polymers typically have clarity of 92-98 %T.
To obtain optimum clarity we recommend the
following:
• Use deionized water.
• Use Direct Method for Polymer Dispersion.
When using self-wetting polymers they should be
dispersed in water, not a water/alcohol mixture.
Reference TDS-103 for details on dispersing
traditional grade Carbopol polymers.
• Choose the correct neutralizing amine. It is
important to insure that the neutralizing amine is
compatible with the alcohol. Reference guidelines
provided.
• For maximum clarity, target appropriate pH.
We recommend the following pH:
� For Carbopol polymers such as Ultrez 10, 940
and 980, the optimum pH is typically around
7.0.
� For Carbopol Ultrez 21 and Ultrez 20 polymers,
the optimum pH is 5.8-6.3.
� We recommend evaluating various pH levels
and neutralizing amines to determine which
combination provides the best clarity for your
specific formulation.
• Choose a water-soluble emollient. Optimize use
level to provide best balance of clarity and
conditioning aesthetics.
• Use water soluble dyes. Examples of appropriate
colors are D&C Red #33, D&C Green #5,
and FD&C Blue #1. Dyes supplied as powders
should be made into dilute (1-3 wt%) solutions and
added at the end of the formulation.
• Addition of oil soluble fragrances. These
ingredients should be post added at low levels. A
solubilizer such as Polysorbate 20 at about 0.2
wt% may be necessary to insure good clarity.
• Filtration of end product will maximize final
clarity.
TDS-255
Formulating Hydroalcoholic Gels with Carbopol ® Polymers
Page 6 of 6
Frequently Asked Questions
• Hand hygiene in healthcare settings.
The US Center for Disease Control (CDC) has
issued guidelines for hand hygiene in healthcare
settings in order to more effectively reduce the
spread of hospital-based infections by healthcare
professionals. The CDC’s guideline, released in
October 2002, strongly recommends alcoholbased
hand sanitizers as the primary method of
hand hygiene among healthcare professionals
when hands are not visibly soiled. The World
Health Organization (WHO) issued “Hand Hygiene
in Health Care Guidelines” in May of 2009.
The following is a link to that document:
http://whqlibdoc.who.int/publications/2009/978924
1597906_eng.pdf
• Safety of direct food contact after using an
alcoholic hand sanitizer?
Using an alcoholic hand sanitizing gel is generally
considered safe. In Canada, workers in the food
industry are allowed to use alcoholic hand
sanitizing gels since they have been approved by
Health Canada. These systems are listed by the
Canadian Food Inspections Agency as acceptable
non-food chemical products. In the food service
industry, an alcohol sanitizer is considered helpful
as an extra hand disinfecting step after washing of
hands with soap and water. The FDA has approved
Carbopol polymers for indirect food contact when
used in hand sanitizers up to 0.5 wt%.
• Protection in Schools.
According to a study issued in October of 2000 in
The American Journal of Infection Control, the use
of hand sanitizing gels was shown to decrease
absenteeism due to illness among elementary
school students by 20%.
• Acceptance of Hand Sanitizing Gels.
According to a study published in the July, 2000
issue of Infection Control and Hospital
Epidemiology, use of a Hand Sanitizing Gel is
accepted by healthcare workers and does not
result in skin irritation and dryness when
compared to frequent soap and water hand
washing.
• Regulations.
Hand Sanitizing Gels may be regulated as drug
products. Review your country’s regulations to
insure compliance.