Pros and Cons of Preserving Lotion with Sodium Benzoate and Sodium Dehydroacetate?

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Pros and Cons of Preserving Lotion with Sodium Benzoate and Sodium Dehydroacetate?

Posted by spadirect on July 8, 2018 at 12:04 am

I am formulating an O/W body lotion with a target pH of 5.4 and shelf life of 18 months. I am considering using Sodium Benzoate and Sodium Dehydroacetate (INCI: Aqua, Sodium Benzoate, Sodium Dehydroacetate; Brand Name ISCA’s Aquaguard 9093) as the preservation system.

What are the pros and cons of using Sodium Benzoate and Sodium Dehydroacetate as the preservation system for this type of body lotion? Are there any other preservatives that could be used in addition to Aquaguard 9093 to fortify and improve the action of its weaker antibacterial and anti-mold characteristics?

Any thoughts, comments and suggestions would be greatly appreciated. Thanks.

Gunther replied 6 years, 4 months ago 6 Members · 8 Replies
8 Replies

belassi

Member
July 8, 2018 at 2:25 am

I had poor results (destabilisation of perfectly good formulations) when I tested dehydroacetic acid. I have no idea whether the sodium salt will do the same, but I imagine it dissociates in water to dehydroacetic acid.
Sodium benzoate is mainly anti-fungal but it will be ineffective at your required pH with only about 8% effectiveness. Therefore I think this is a pretty poor choice on both counts.
I would use either KEM NAT or Spectragard, they are both excellent, I’ve been using Spectrastat for years and have never had a failure at 0.7%
spadirect

Member
July 12, 2018 at 8:34 pm

Which preservative system do you suspect may have a more effective broad spectrum action while maintaining lotion stability in an O/W leave-on body lotion (target pH range 5.4 - 5.6, 18 month shelf life) between the Akema Fine Chemicals’ preservative product brands KEM NAT (Benzyl Alcohol, Glyceryl Caprylate, Glyceryl Undecylenate) or KEM NAT β (Benzyl Alcohol, Glyceryl Caprylate, Benzoic Acid, Propanediol)?

Thanks!
OldPerry

Member
July 12, 2018 at 9:01 pm

Cons:
+You have to formulate at a pH below 5.0.
+Benzoates can be allergens. https://www.the-dermatologist.com/content/update-benzoates
+They can destabilize emulsions
+Less reliable than parabens

Pros:
+Can claim paraben free.

IMO - the cons outweigh any pros.
Dtdang

Member
July 12, 2018 at 11:53 pm

I just read about sodium levulinate that is good preserve and also good for skin. It is similar to bees using it to protect its nest.
Microformulation

Member
July 13, 2018 at 12:01 am

Sodium Levulinate is not a great preservative for a Beginner. Walk first.
Dtdang

Member
July 13, 2018 at 1:19 am

Thanks. Can you explain more details why? Thanks in advance
Microformulation

Member
July 13, 2018 at 1:29 am

It requires a overall hurdle approach and is tricky to use. It is very much cGMP compliant. It is not a starting preservative.
Gunther

Member
July 13, 2018 at 3:50 am

In this benzoate vs methylparaben head-to-head study

ANTIMICROBIAL EFFICACY OF THE METHYLPARABEN AND
BENZOATE SODIUM AGAINST SELECTED STANDARD
MICROORGANISMS, CLINICAL AND ENVIRONMENTAL
ISOLATES IN VITRO

You can see in Table 1 that Sodium benzoate requires high concentrations, sometimes well beyond those allowed in cosmetics or foodstuff, to properly preserve the product.

i.e. in S. aureus (Clinical) it needs 10 exp 1 =10 mg/ml = 1%

Compare this to Table 2 where the highest methylparaben concentration needed was 10 exp -3 = 0.001 mg/ml = 0.0001%

On the bright side, a Sodium benzoate Pro is that it easily dissolves in water, unlike parabens.
I hope to conduct Parabens + Sodium hydroxide tests results by the next week
https://chemistscorner.com/cosmeticsciencetalk/discussion/4485/has-anyone-reacted-parabens-with-sodium-hydroxide-to-make-paraben-sodium-salts