Another dangerous product

Belassi

As many of you know, I am against the use of isothiazolinones after personal experience with having both of my dogs suffer atopic dermatitis (AD) due to a shampoo containing it.
Now, I've had another case, my daughter, in her mid 30s, with scalp irritation and her hair falling out. The symptoms went away after I checked the label on the SEDAL CONDITIONER she was using, and advised her to stop using it. Yes, isothiazolinones again. I had to use a x100 eyepiece to read the label, maybe there's a reason they print it unreadably tiny... they don't want us to read it. I have begun campaigning against this product.

letsalcido

https://www.mdedge.com/dermatology/article/206178/contact-dermatitis/methylisothiazolinone-and-isothiazolinone-allergy

I think targeting a company or product for using a compound that until recently was (seemingly) standard/widely accepted and generally regarded as safe is not the way to go about this. 

Here in the US I have several comercial products containing MI and MCI. Some of which are higher-end cosmetics.

Perhaps the efforts should be directed at educating people about these compounds, and the risk to sensitization they pose in some of the population, not turn them against one (of possibly tens of thousands) of the products containing it.

Just my two cents.

Pharma

I've never been a fan of these, especially not in products for direct contact with humans & animals, and was saying so for over two decades now.

The main issue of such allergens and not just isothiazolinones is not their chemistry but that they're often excessively used in many different products of everyday life such as washing detergents (dishes, clothes, cars, you name it), paints, lacquer, glue, fertilisers, pesticides & other agrochemicals, all kinds of industrial liquids down to the stuff used to build our houses, colour our clothes, or clean machines which process our food. I don't have actual numbers for MIT & CMI but these are produced in many million metric tons per year (guess who sells a metric ton as MOQ?). MIT, CMI and other isothiazolinones are present in nearly everything (literally nearly everything!) which contains water at some point in its production process and isn't meant for consumption such as paper and in a lot (= estimations talk of ~50%!) of materials potentially degraded by microbes such as fillings and insulation materials. It is virtually impossible to live in a halfway modern world without getting in constant contact with these chemicals and that's the main issue. No, not just for these two but for nearly every similar product and we will see exactly the same shit going down with 'modern', 'better', and more 'natural' preservatives (as of now, my bet is on caprylhydroxamic acid when it comes to cosmetics).

At least, isothiazolinones have been regulated in cosmetics and allergy prevalence is going down slowly since that day. But, as said 'same shit, new name' is so far all humanity managed to produce in too many fields of our lives. We need to rethink the basics and not just find ways around legislations because we can cheat customers and dupe politicians but we can't cheat nature and we can't dupe biology.

Belassi

They don't heed customer complaints, I see no other way. Give me another ten minutes and I will have set up a new group against them, on Facebook. I am pretty good at getting a lot of hits with my boosted posts.

Abdullah

@Pharma what is the problem with caprylhydroxamic acid? 

I use it with glyceryl caprylate and glycerin (Spectrastat™ G2-NMB) thinking it is the most gentle preservative i can get. 

Although it is very expensive

Pharma

I've worked with hydroxamates and even synthesised some SAHA derivatives. Hydroxamates have been on the drug developers no-no list for years for more or less good reasons (such as mutagenicity) but certain derivatives like vorinostat aka SAHA are now developed as promising drug candidates for example as histone deacetylase inhibitors (cancer therapy). Hydroxamates aren't harmless compounds and are powerful chelates mainly for zinc and hence, inhibit a broad set of zinc dependent enzymes.

Caprylhydroxamic acid is the core structure of several of the mentioned HDAC inhibitors and that's what makes me wary. Sure, not all hydroxamates are inherently toxic, some are quickly metabolised to their corresponding carboxylic acids. But for now, knowledge and predictability are poor. Cancer treatment is a different story than widespread use as preservative. I don't dare thinking of what might happen should caprylhydroxamic acid become a replacement for parabens or thiazolinones... my imagination associates that picture with the glyphosat aka Roundup disaster.

Abdullah

@Pharma what about other chelators like sodium phytate?

We use it in every product to help preservative and to rise the pH if necessary.

How chelating effect of these two compared? 

Pharma

Phytic acid and its salts are highly hydrophilic and do neither penetrate skin nor microbes. Caprylhydroxamic acid is a weak acid and has just the right logP so it can accumulate in microbes but this also means it's skin permeable.

Its weak acidity makes it a less pH dependent chelate but increases the possibility that bound metals become soluble in the oil phase. Given that it forms quite stable metal complexes makes it impossible to predict the pros and cons of the two vs. each other.

Healthwise, phytate is certainly safer (it's something we eat nearly every day since time immemorial).

LuisJavier

@Pharma what is the LogP range for chemicals being permeable to the skin? Would something like acetic acid not be absorbed into the skin if left in a 5% solution, for example, on the scalp?