The current Covid-19 global health crisis has alerted us to the fact that regular hand washing and use of sanitisers is a critical component in the fight against the spread of viruses and infection. Whilst washing your hands thoroughly with soap and water tops the list for keeping yourself safe through from the Coronavirus outbreak, hand sanitisers provide a convenient and highly effective way to disinfect and protect yourself and others from disease.
But here’s the catch. Not all hand sanitizers will do the job as well as others. The 8 point checklist below will assist you when making the critical decision which sanitiser to purchase and how this could affect your ability to control the spread of infection in your workplace.
How does hand sanitizer work?
The key ingredient in most hand sanitizers is alcohol. Chemically speaking, alcohols are organic molecules made of carbon, oxygen and hydrogen. Ethanol is the chemical in alcoholic drinks and is the chemical most people are thinking of when they say alcohol.
Alcohols such as Ethanol destroy disease-causing agents, or pathogens, by breaking apart proteins, splitting cells into pieces or disrupting a cell’s metabolism. For a virus, sanitizers work by disrupting the virus’s outer coat and for a bacterium, they work by disrupting its cell membrane. The novel coronavirus, for instance, is an enveloped virus surrounded by a fat layer. Lipid membrane viruses—like the coronavirus—can be killed using alcohol-based disinfectants and hand sanitizers. They simply break down the membrane or the layer of fat, leaving the virus unable to infect an individual.
Solutions with as little as 30% alcohol have some pathogen-killing ability, but the effectiveness increases significantly with increasing alcohol concentration. Studies have shown that alcohol kills a more broad variety of bacteria and viruses when the concentration reaches 70%. Above this concentration the effectiveness tends to flatten as a little water mixed with it improves penetration and prevents evaporation. Another strength of alcohol is that the bacteria it kills don’t develop a resistance to it, so alcohol doesn’t lose effectiveness with continued use.
So what is the ideal formulation?
As previously mentioned an ethanol content of 70% is usually used for most medical-grade sanitisers. This is measured as Volume/volume percentage (v/v %) which is a measure of the concentration of a substance in a solution. It is expressed as the ratio of the volume of the solute to the total volume of the solution multiplied by 100. To avoid contamination, it is strongly recommended that pure water is used, this could include distilled or reverse osmosis methods.
It is also essential that this formula is accurately checked and correlates with the label on the packaging, furthermore it is expected that manufacturers can provide written evidence that each batch has been verified and an SDS provided as required. It is of all importance that end users can ensure that a minimum of 60% ethanol has been used (ideally 70-80%) and that this is fully traceable to the manufacturers procedures, otherwise the users’ safety could be compromised – beware of low cost substandard product! Glycerol (Glycerine) is also recommended as a humectant (moisturising agent), the addition of fragrances is not recommended and it is important that only pharmacopeia quality reagents are used.
A variety of sub methods are used depending on the application – these include:
- Gel Hand Sanitisers – This is often preferred as it is easy to dispense and spread across the hands. Most gel sanitisers contain added emollients (moisturisers) and gelling agents such as aloe vera. Care needs to be taken to ensure that additives are non-toxic and hypoallergenic (unlikely to cause an allergic reaction). Always check the SDS to ensure that there are no potentially harmful ingredients.
- Liquid Hand Sanitisers – This is generally used in automatic dispensers as a spray. Advantages include: Good coverage on the hands, fast application times, and rapid drying. Disadvantages are: Messy to use and larger volumes consumed. Often these are supplied in bulk (5-20Lt) and users replenish their own dispensers. Care needs to be taken to ensure that the product is not comprised in any way during storage, preferably in a flammable storage cabinet.
- Other – The WHO recommends an 80% v/v sanitiser with a small amount of Hydrogen Peroxide to eliminate any contaminating spores within the bulk solutions. Note that this formula is mainly recommended for smaller production facilities including small DIY manufacturers and inhouse production.
Packaging and Labelling
It is essential that hand sanitiser is packaged and labelled according to national and international guidelines. These recommendations include:
- End-user containers should not exceed 1000ml to prevent evaporation (Bulk solutions may be supplied in larger volumes).
- Labelling should include Ingredients; Directions for use; Warnings; Date of manufacture and/or Expiry date. It should also clearly state the local manufacturer and/or distributor.
- The product should not be presented in a way that is likely to result in the goods being mistaken for or confused with food or beverages. This is to address about children potentially mistaking hand sanitisers supplied in inappropriate containers as food or drink. Examples of inappropriate containers include foil sachets, pouches with a spout or containers with a pop-top lid.
- Gel containers should have a robust dispensing pump that dispenses 1-1.5ml per pump.
Storage and Use
Since ethanol is flammable, care needs to be taken that it is stored in the appropriate area and that local storage guidelines are adhered to. It is recommended that larger volumes are stored in designated Flammable goods cabinets, if these are not available ensure that it is kept in a cool dry place away from any direct sources of ignition. Always ensure that it is stored away from children and used with adult supervision. If skin irritation occurs wash immediately with water.
It is important to note that that hand rubs used without water may not work well when hands are visibly dirty. Ensure that adequate training in effective handwashing routines is carried out regularly. Follow directions given on the label at all times.
Most countries have regulatory authorities who promote and protect public health by ensuring that over the counter medicines are of the required quality, safety and efficacy. It is important that this is checked to ensure that your hand sanitiser meets any national safety standards, especially in clinical environments. The WHO also has a guide for local production of recommended hand rub formulations.
- Does the sanitiser meet the required alcohol concentration
- Is this verified and clearly marked on the label and SDS?
- Ensure the sanitiser does not contain any harmful additives – again check the SDS
- Do you require a gel or liquid?
- Is the dispensing mechanism practical and safe?
- Does the packaging and labelling meet local regulatory requirements?
- Are you storing bulk amounts safely?
- Does your sanitiser meet national regulatory guidelines?