PRESERVATIVES
Table 5: Challenge test results at Day 7 using 6% Zemea + 0.25% preservative levels. Gram-positive
Gram-negative
Phenoxyethanol-based preservatives Microcare PM3 (0.075%) Euxyl PE 9010 (0.125%) Neolone PE (0.15%)
Natural preservative Lexguard Natural (0.25%)
Organism count at Day 7, CFU/g
Bio-derived propanediol worked well with the phenoxyethanol-based preservatives and boosted the preservative efficacy for gram-positive, gram-negative, and yeast organisms.
Bio-derived propanediol consistently boosted the efficacy of each preservative tested with Aspergillus niger.
Bio-derived propanediol worked well with the natural based preservatives and boosted the preservative efficacy for yeast and moulds.
Bio-derived propanediol may allow the use of less preservative in formulations while providing additional performance benefits such as no skin irritation, increased humectancy and excellent aesthetics.
Bio-derived propanediol is not a preservative nor is it considered an active ingredient.
Experimental design – B Consistent with experimental design A, the results of a second CTFA challenge study are described. The base emulsion formula (Table 1) and preservative systems (Table 2) were used with minor changes listed for both. The Dermosoft 688 ECO and Geogard ULTRA were excluded for this study.
The study evaluated the base emulsion
formula (Table 1) with a constant level of 6% bio-derived propanediol and with the
preservative systems tested at one-quarter their recommended use level. Table 5 shows the challenge test results at Day 7.
Results Bio-derived propanediol worked well with the lower preservative levels and boosted their efficacy for Gram-positive and Gram-negative organisms.
Bio-derived propanediol consistently boosted the efficacy of the phenoxyethanol-based preservatives tested with Aspergillus niger.
Experimental design – C Consistent with experimental design A, the results of a third CTFA challenge study are described. The base emulsion formula (Table 1) used in this study replaced the bio-derived propanediol with butylene glycol and the preservative system levels were used as described in Table 2. The Dermosoft 688 ECO and Geogard ULTRA were excluded for this study. The study evaluated the base emulsion
formula (Table 1) with a constant level of 4% butylene glycol and with the preservative systems used at one-half their recommended use level. Table 6 shows the challenge test results at Day 7.
Results 4% butylene glycol did not work well with the preservative levels used in this study.
Gram-negative Gram-negative
4% butylene glycol inconsistently boosted the efficacy with Gram-negative and yeast organisms.
Conclusion
Zemea bio-derived propanediol is the world’s first 100% natural glycol replacement approved by ECOCERT and certified by the Natural Products Association. With its skin-friendly performance, including no irritation, enhanced moisturisation and excellent aesthetics, Zemea is seeing rapid adoption around the world in skin care, hair care, deodorants, fragrances, and other cosmetic and personal care products. Based on rapidly renewable resources, Zemea can successfully replace petroleum-based glycols or glycerin in many natural and traditional personal care formulations. Formulators may be able to reduce the amount of preservatives used in their formulations with the inclusion of this natural glycol replacement.
Acknowledgements The authors would like to thank Irwin Palefski, Cosmetech Laboratories for his consultation and formulation expertise.
Footnote 1 Zemea®
Table 6: Challenge test results at Day 7 using 4% butylene glycol + 0.5% preservative levels. Gram-positive
Phenoxyethanol-based preservatives Microcare PM3 (0.15%) Euxyl PE 9010 (0.25%) Neolone PE (0.3%)
Jeecide CAP-4 Optiphen (0.25%)
Natural preservative Lexguard Natural (0.5%)
Organism count at Day 7, CFU/g 88 PERSONAL CARE April 2012 propanediol is a registered trademark of DuPont Tate & Lyle Bio Products LLC.
Gram-negative
Yeast
Mould Staphlyococcus aureus Escherichia coli Pseudomonas aeruginosa Candida albicans Aspergillus niger
<1.00 <1.00 <1.00
Jeecide CAP-4 Optiphen (0.125%) <1.00 <1.00
<1.00 <1.00 <1.00 <1.00
<1.00
<1.00 <1.00 <1.00 <1.00
<1.00
DNP DNP DNP DNP
3 Log reduction
2 Log reduction 2 Log reduction <1.00 <1.00
DNP
PC
Yeast
Mould Staphlyococcus aureus Escherichia coli Pseudomonas aeruginosa Candida albicans Aspergillus niger
DNP DNP DNP DNP
<1.00
DNP DNP DNP DNP
<1.00
DNP DNP
<1.00 4 Log reduction DNP
DNP DNP
1 Log reduction DNP
2 Log reduction
DNP DNP DNP DNP
DNP
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