Natural non-preservative preservative.. active against Candida Albicans?

Zink

I got USP51 results back for a sunscreen formula and it failed (barely) against Candida Albicans. Any ideas of the gentlest ideally natural option that aren't sun sensitizing? 

It seems Lauric Acid could be an excellent choice here, showing great killing ability of C.Albicans at only 0.05% concentration in-vivo. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC90807/ - a few x more potent that Capric Acid which I'm already using.

Another option could be Glyceryl Caprylate Caprate.

Thoughts?

Bill_Toge

what's your formula, what's the pH, and what preservative(s) are you currently using?

Microformulation

You may want to call Technical Services at Lincoln Fine Ingredients since the preservatives you are citing are right down their alley.

http://www.lincolnfineingredients.com/

Zink

@Bill_Toge Formula is basically a silane coated zinc oxide sunscreen with caprylic/capric triglycerides emulsified by olivem 1000, stabilized by xanthan gum and glyceryl stearate. Currently using no preservatives, will be packaged in airtight bottle, pH 7. 

@Microformulation thanks will do, I'll let ya'll know what they say.

Microformulation

You may also want to look at the Inolex Spectrastat line. Of interest, on April 25th they are doing a webinar on the Hurdle Technique;

https://vts.inxpo.com/scripts/Server.nxp?LASCmd=AI:4;F:QS!10100&ShowKey=39449

I get a bit leary of the term preservative free when it is applied to non-standard preservatives that are in fact exerting a preservation function. Preservation is part of a well-designed Formulation and I dislike the temptation to try and make this claim behind a marketing bias. In my experience the bias against preservatives as a whole is minor and in fact, any bias is directed towards individual classes such as parabens and formaldehyde donors. If it is preserving, it is properly a preservative. Like the term Chemical, the term Preservative has a clear definition.

Zink

@Microformulation I get what you're saying, but you can call it preservative free and still explain that it contains (natural) ingredients acting preservatives that are not classified as (synthetic) preservatives right under that claim, you could also include the lab name and log # of the challenge test. To me that's the best way to go about it.

Talked to Lincoln and waiting for their docs, their MOQ is 40 lb BTW.

Microformulation

Well, I hate the word natural. I won't go into depth since I am sure I have covered it before ad nauseum.

Remember "natural" versus "synthetic" is not an analogy of "safe" versus "dangerous."  I know the market urges us to endorse that, but I refuse as a hardcore pure "Scientist." Be a Scientist first, then let the marketing be written in such a way that doesn't compromise your integrity. That is just me on my soapbox. I will say that this stance has not limited any of my product lines. Several have grown to multi-million dollar accounts which are in larger retailers. One was recently bought out and that client has effectively "retired." DON'T FEEL LIKE YOU NEED TO PANDER AT THE EXPENSE OF THE SCIENCE.

I probably wouldn't post the lab name (they may not approve of the publicity) and when you provide too many details it either goes over the head of the client or it invites way to many questions. Years ago I used to share my stability protocols with clients and believe me it lead to many naive questions that took up way too much time.

I will put that out there. No need to respond as it is off topic. I think you will (as many have) evolve to this sort of view point over time independently.

Zink

I have always had this point of view.

Devil is in the details, synthetics can be safer than naturals and vice versa. But if you can use fewer additional ingredients that only function to preserve a product then that's good design and possibly good for long term safety as long as the preservation is robust.

I'm all with you on retaining integrity in your marketing, which I think you can do whilst ticking off some marketing boxes. Most people don't care either, and just want something that either makes their skin feel nice or in the case of skin diseases makes the disease go away ASAP.

Details such as lab name can be subtly shared for those who are looking if the lab is fine with it, really a question of good graphic design where you have your information hierarchy sorted out. Not something that would go on the front packaging. At the very least I'd say it's challenge tested; people are wisening up about the risks of naive preservative free formulas.

DRBOB@VERDIENT.BIZ

#zinc Why don't you raise concentration of preservative being used unless you are at maximum levels.Logarithmic report on growth should provide clue --had similar problem which doing the latter made it easy.

Zink

@DRBOB@VERDIENT.BIZ The lowest hanging fruit here is to add ~1% Lauric Acid and have that tested.

If that doesn't work try adding 1% Glyceryl Caprylate Caprate instead. Increasing the amount of caprylic/capric acid could also work.

Bill_Toge

personally, I've always taken the view that the term 'self-preserving' is more factually accurate, and less likely to land you in legal hot water than 'preservative free'

also, I understand glyceryl laurate is equally effective as an antimicrobial, and less likely to make your product foam than lauric acid (that said, I've never used it personally, so take this with a pinch of salt)

Zink

I don't see why you cant use both: "Preservative Free. Self-preserved by alcohol" or whatever else. 
What people are concerned with are synthetic preservatives.

Perry

Many people are concerned about alcohol too.

But to the "preservative free" claim.  This claim makes more sense in the EU as they have a specific list of approved preservatives. If you don't use any of those ingredients then by regulatory definition, you are preservative free.

I would consider it false if you made the claim in the US but in the EU, it seems to work with the regulatory system. Except of course, that rule that disallows any "free from" claims.  

Bill_Toge

my view is that "preservative free" is much more open to legal challenges

if the formula has a high enough water activity and an appropriate pH to sustain growth but doesn't actually do so in practise, the only logical conclusion is that a material, or combination of materials within it is acting as a microbistat or a microbicide

and it would not be unreasonable for microbistatic / microbicidal materials like this to be regarded as preservatives in a court of law, whether or not they are intentionally added for this purpose, and whether or not they're listed on Annex V

Microformulation

"What people are concerned with" (Marketing) is irrelevant when discussing Regulatory Affairs (Scientific Compliance Standards).

Bobzchemist

I agree with Bill. Given the prevalence of lawsuits these days, claiming "preservative-free" is just asking to be sued.

johnb

I don't know if this will add anything to the discussion but lactic acid in the form of yoghourt is an effective folk remedy for Candida infections.

Lactic acid at a suitable concentration also acts as a moisturiser and general "good" item for skin products.

Zink

"Preservative free. Self-preserved by alcohol." or "Preservative free; free of synthetic preservatives. Preserved by natural ingredients."

There: Have your cake and eat it too.  AFAIK what (a minority) of people are concerned with are synthetic preservatives. I don't see how either of the above would be "asking to be sued" please elaborate.