How, when and why do formaldehyde donors release formaldehyde?

Suppose DMDM hydantoin for example in a Shampoo formula. It has formaldehyde but it is not free at first.

Here are some questions.
1. Does it releases the Formaldehyde by Time? For example release specific percentage each month until all of them are released?

2. Does it release formaldehyde when it is needed? For example if it gets contaminated it releases some formaldehyde to kill the microbes and if didn't get contaminated don't release formaldehyde too?

3. Or it has any other plan on when to do or don't release formaldehyde?

Comments

  • Bill_TogeBill_Toge Member, Professional Chemist
    it releases formaldehyde when microbes attempt to ingest it, in the same way that parabens release alcohols when microbes attempt to ingest them
    it also starts to release formaldehyde in alkaline conditions, or when exposed to temperatures over around 50-60 °C
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • Bill_Toge said:
    it releases formaldehyde when microbes attempt to ingest it, in the same way that parabens release alcohols when microbes attempt to ingest them
    it also starts to release formaldehyde in alkaline conditions, or when exposed to temperatures over around 50-60 °C
    Thanks
  • PhilGeisPhilGeis Member, Professional formulator
    Bill_Toge said:
    it releases formaldehyde when microbes attempt to ingest it, in the same way that parabens release alcohols when microbes attempt to ingest them

    Can you provide the data for these 2 phenomena? 


  • Bill_TogeBill_Toge Member, Professional Chemist
    @PhilGeis the fact that neither 5,5-dimethyl hydantoin (the parent compound of DMDM hydantoin, minus the two formaldehyde equivalents) nor p-hydroxybenzoic acid (the parent compound of parabens) have any microbistatic or microbicidal activity is pretty strong evidence
    UK based formulation chemist. Strongest subjects: hair styling, hair bleaches, hair dyes (oxidative and non-oxidative) I know some stuff about: EU regulations, emulsions (O/W and W/O), toothpaste, mouthwash, shampoos, other toiletries
  • PhilGeisPhilGeis Member, Professional formulator
    edited November 2021
    Bill_Toge 
    That closely related compounds have no efficacy is no proof, strong or otherwise) of bacterial "attempt to ingest" as some controlling mechanism.  Where are the compelling data?
    Formaldehyde releasers maintain 100-200 ppm formaldehyde - an effective level with or without bacteria.  One can can temporarily recued  that level by dialysis and it will be reestablished in a day or so.
    Parabens are sensitive to esterases - why so poorly effective vs. Gram negative that often proceed to degrade the rest of the molecule.  These are extracellular - as are esterases in skin that also degrade the parabens.
  • @PhilGeis does this 100-200ppm corelate with how much formaldehyde releaser like DMDM hydantoin we include in product or it will always be 200 ppm formaldehyde no matter if we add 0.1% DMDM hydantoin or 1 percent? 
  • PhilGeisPhilGeis Member, Professional formulator
    Do not have that information.  Experience - at use levels of ~2500 ppm - 100-200 ppm "free" formaldehyde.    
  • 2500ppm DMDM hydantoin correct?

    How did you check or know what percentage of formaldehyde is free?
  • PhilGeisPhilGeis Member, Professional formulator
    Analytically.  This was needed to stay under EU cosmetic directive labeling re. contains formaledehyde. 
  • PhilGeis said:
    Analytically.  This was needed to stay under EU cosmetic directive labeling re. contains formaledehyde. 
    Thanks
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