Chemical Manufacture - Safety of preservatives
I recently watched a video by BASF about their efforts in minimising ethylene oxide residues in various of their products such as SLES and other ethoxylated ingredients. They were aiming for a level of about 1ppm or less, in addition to explaining potentially new legislation requiring lower ethylene oxide residues. The reason I bring up this information is because it had me thinking about other chemicals, ethoxylated or not and their undesirable and potentially hazardous to health in even very small quantities, whether that be a long-term concern or not.
Am I wrong in thinking that if BASF is making big efforts in reducing the EO residues in some of their products as well as notifying us of formulations that will have to change to be compliant with potentially new legislation as a result of EO residues, that surely this is a topic for the formulator to give moral thought to?
I do not desire to just hand-wave any critical thought/analysis of these chemicals and their impurities because of CIR saying that as of present, these chemicals are safe for use at the accepted usage levels, or because of the argument that these chemicals are in such tiny percentages. No, firstly, tiny levels of these residues is still a concern for me and many others due to knowledge that a product (e.g. a face cream) is not just used once in a lifetime or once a month, but often as frequently as everyday or every other day. Concern over these impurities is possibly the only worry that I share with the ‘natural-only’ crowd on the internet.
Secondly, I appreciate CIR and other such organisations’ research on these topics, but I desire more knowledge of the thought-process behind their decisions when they state something to be ‘safe for use at 0.5% in a leave-on product’. I have read many CIR safety assessments but still have so many questions. I understand that testing data is used to come to such conclusions, but often this is for acute effects. I’m more interested in the long-term effects of the impurities of the said product. For example, if CIR make a safety assessment of 2-phenoxyethanol, they review the acute effects of phenoxethanol and not ethylene oxide. Ethylene oxide residues would like have a long-term effect due to their tiny %.
Benzyl alcohol if introduced to the eyes, can cause corneal necrosis. My phenoxyethanol supplier lists in their MSDS for the chemical that it has a maximum phenol content of 10ppm and I am unaware of the ethylene oxide content, but I’m sceptical about it being EO free. I also found out that ethylene oxide can penetrate the skin and is also readily soluble in water as well as being denser than air, so I do not hope very much that in a formulation, that it will just evaporate away before the product (e.g. face cream) is applied. Caprylhydroxamic acid in Spectrastat may have hydroxylamine residues which is at least a suspected human carcinogen.
Sodium benzoate can form benzene if it reacts with ascorbic acid at even room temperature. Now, I will admit, the kind of face creams that I formulate, I do not have a worry about benzene formulation because I do not use ascorbic acid or its derivatives and the oils and butters that I use, as far as I’m aware, don’t contain vitamin C, and even if they did, it would not only be a small amount, but for that small amount to react with the already tiny amount of sodium benzoate in the product, in the presence of an emulsion, is something that I would not really worry about. I am however quite averse to formaldehyde releasers due to client reactions to these kinds of chemicals.
Sodium anisate and sodium levulinate do not seem so cost-effective due to their effective usage levels, and they seem difficult to incorporate due to their very small pH window for adequate efficacy. Potassium sorbate is a chemical that so far I have not really read up anything negative about except skin reddening due to the sorbic acid on capillaries on the face, and the rather low pH for it’s efficacy.
So, after everything I’ve written above, if I have said anything that you think is logically inconsistent or factually wrong, please let me know. If you feel that some information would be useful to me in regards to the above, please point me in the right direction or just let me know. Alternatively, you can let me know of a preservative system that you think I would not object to. Thank you!
*Edited for formatting (PR)