Formulating Hydroalcoholic Gels with Carbopol Polymers

Transcription

1 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 s 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 v/v% Isopropanol at 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. Lubrizol Advanced Materials, Inc. / 9911 Brecksville Road, Cleveland, Ohio / TEL: or combination with other substances or in the User s process. Due to variations in methods, conditions and equipment used commercially in processing these materials, no warranties or guarantees are made as to the suitability of the information or products for the applications disclosed. Lubrizol shall not be liable and the User assumes all risk and responsibility for any use or handling of any material beyond Lubrizol's direct control. LUBRIZOL MAKES NO WARRANTIES, EXPRESS The information contained herein is being furnished for informational purposes only, upon the express condition that the User makes its own assessment of the appropriate use of such information. While the information contained herein is believed to be reliable, no representations, guarantees or warranties of any kind are made as to its accuracy, suitability for a particular application or the results to be obtained herefrom. Lubrizol Advanced Materials, Inc. ("Lubrizol") cannot guarantee how any products associated with this information will perform in Lubrizol Advanced Materials, Inc. is a wholly owned subsidiary of The Lubrizol Corporation All trademarks owned by The Lubrizol Corporation Copyright 2012 / The Lubrizol Corporation OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, For further information, please visit: THE IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. It is the User s sole responsibility to determine if there are any issues relating to patent infringement of any component or combination of components relating to the supplied information. Nothing contained herein is to be considered as permission, recommendation, nor as an inducement to practice any patented invention without permission of the patent owner.

2 Formulating Hydroalcoholic Gels with Carbopol s Page 2 of 6 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. 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 Ultrez 10 Ultrez 21 Ultrez 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 Comparison Use Level of Carbopol 0.1 wt% 0.2 wt% 0.3 wt% 0.4 wt% 0.5 wt% Deionized Water (wt%) Ethanol (wt%) TEA (wt%)

3 Clarity Results: %Transmittance at 420 nm TDS-255 Formulating Hydroalcoholic Gels with Carbopol s Page 3 of 6 Clarity of Hand Sanitizing Gels Clarity, %T Carbopol 940 Carbopol 980 Carbopol Ultrez 10 Carbopol Ultrez 21 Carbopol Ultrez % 0.30% 0.50% Concentration, wt% TS Viscosity Results: Brookfield RVT, C Viscosity of Hand Sanitizing Gels 25,000 Viscosity, mpa s 20,000 15,000 10,000 Carbopol 940 Carbopol 980 Carbopol Ultrez 10 Carbopol Ultrez 21 Carbopol Ultrez 20 5, % 0.30% 0.50% Concentration, wt% TS

4 Formulating Hydroalcoholic Gels with Carbopol s Page 4 of 6 Neutralization of Carbopol s 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 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 Trade Name INCI Name Manufacturer Alcohol Level Neutralization Ratio* Base/ Carbopol 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 Carbopol polymers Rheology modifier Alcohol Disinfecting agent Fragrance Botanical Actives Specialty Silicones

5 Formulating Hydroalcoholic Gels with Carbopol s Page 5 of 6 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 s: 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 s: 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. 2. Add the alcohol with slow mixing to de-aerate the formulation if it was not included in Step 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 % (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 wt% addition will not impact the final product clarity. Trade Name Glucam E-20 Humectant Glucam E-10 Humectant SilSense Copolyol-1 Silicone SilSense SW-12 Silicone Ester Hydramol PGPL Emollient Hydramol PGDS Emollient INCI Name Methyl Gluceth-20 Methyl Gluceth-10 PEG-33 and PEG-8 Dimethicone and PEG-14 Dimethicone PEG-7 Cocoate PEG/PPG-8/3 Laurate PEG-90 Diisostearate The Hydramol emollients can be added at use levels from 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.

6 Formulating Hydroalcoholic Gels with Carbopol s Page 6 of 6 Clarity (% 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 %T. To obtain optimum clarity we recommend the following: Use deionized water. Use Direct Method for 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 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. 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 The following is a link to that document: _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.