Actives like botanicals, pH, packaging material (plastics), nonionic surfactants and interactions with actives or excipients , too irritable...
It seems like every time I think I have the right preservation for a certain concoction, there is always something that gets in the way of the preservative...
But let's not get desperate, so I hope I can get some help with the following questions.
- I see phenoxyethanol, benzyl alcohol or parabens being used in a lot of stuff where also nonionic surfactants are being used.
I read that even 3% of polysorbates can already inactivate your preservative. How the hell do they keep it right with those combinations? Like a moisturizer with cetyl alcohol aswell as phenoxyethanol. Do they use higher concentrations of the preservative?
- Most of the products are kept in plastics. But there are lots of interactions between them.
Benzyl alcohol by polyethylene, sorbic acid/sorbates by plastics (polypropylene, PVC and polyethylene, phenoxyethanol by pvc plastic, cellulose based excipients.
Can I really keep on using my standard plastic airless dispensers?
I don't have a cosmetic business, so I can't check my preparations for microbial growth. Instead I try to emulate already existing formulations, only use it for max. 3 months or so. I add glycerin and other polyols and a silicone (cyclopentasiloxane), no bugfood like oatmeal, honey etc, no jars but dispensers, keep it in the fridge, work as clean as possible (disinfect packaging, erlenmeyers, spoons etc., no bare hands but gloves when weighing and preparing), boil the demi water I use for about 15-20 mins.
These are the preservatives I have right now that I can get my hands on (suppliers are scarce here) I use combi's to try to be as broad spectrum as possible
- benzyl alcohol ;
_ dehydroacetic acid;
- potassium sorbate
Answers on questions above + tips/advice: very welcome.