Preserving the faith. A cosmetic formulators overview John Woodruff

Transcription

1 Preserving the faith A cosmetic formulators overview John Woodruff

2 John Woodruff: the personal stuff 1960: joined Smith & Nephew Research 1976: Co-founded Pava, responsible for all technical aspects, from formulation and development to manufacture and filling and originated many well-known brands. October 1988: Established consulting laboratory for formulation of cosmetics and toiletry products. Developed Creativity a unique programme written for formula creation and cosmetic manufacture Two books and many articles published on cosmetic technology. Twice appeared as an expert witness, 3 times Chairman of the European UV & Sun Filters Conference, Twice chaired a technical session at In-Cosmetics : Cosmetics Consultant to Manufacturing Chemist 1996 Present: Regular contributions to Soap, Perfumery and Cosmetics (SPC) Supports the Distance Leaning Course run by the SCS Lectures on product formulation at the Principles and Practice of Cosmetic Science When he is not working he is sailing. 2

3 The cosmetic product brief Product type Claims Product format Application Texture Colour Perfume Packaging Cost 3

4 What about the preservative? Preservatives are one of the last things that most chemists think about when formulating a product and one of the first things that are suspected when a problem occurs. They are important ingredients, the value of which is never noticed when functioning properly and which are worthless when not. Preservatives are much maligned and misunderstood within the cosmetics industry. Because of this, they are often over-dosed, under-dosed or improperly formulated even by experienced chemists Cosmetic formulations require a delicate balance of a large number of raw materials. The preservative system should be among those materials considered when developing a new formula, not an afterthought Schϋlke 4

5 The legal stuff EU Cosmetics Regulation (EC) No. 1223/2009 Cosmetics must be resistant to microbial contamination Preservative efficacy must be assessed experimentally to ensure microbial stability and preservation during storage and use SCCS/1501/12 gives guidance for the testing of cosmetic substances and includes guidelines on microbiological quality of the finished cosmetic product For cosmetics sold in Europe (EC) No. 1223/2009 lists a table of permitted preservatives as Annex V This list was first compiled in 1982 and more than half are not in general use and there have only been two new ones added in the last decade The prohibitive cost of gaining acceptance for any new ones will severely restrict any future additions 5

6 The problem A presentation from Inolex, Cosmetic Preservation, Market Review, makes the very valid point that the internet gives voice to all, regardless of qualification and that Real science and Junk science are given the same credibility by an illinformed public Consumer, environmental and political groups are capitalising on this to move their cause forward And so are cosmetic companies And ingredient suppliers 6

7 The result For various reasons consumers do not like preservatives in general and parabens in particular; this makes cosmetic preservation even more difficult The limited number of available preservatives increases the risk of developing resistant strains of bacteria. It also increases the risk that consumers will develop allergic reactions to the preservative and a diverse palette is needed Valérie Murset of the *EFfCI The biggest issue confronting the preservative market is the potential for misinformation to impact a formulator s choice in product preservation and imperil consumers Mark Miller, McIntyre *EFfCI - European Federation for Cosmetic Ingredients 7

8 The formulators challenge Stay legal in all potential markets lack of harmonisation between EU, USA, Japan, Brazil, Australia etc. Please the marketing department who are trying to please consumers Provide adequate preservation throughout the life of the product shelf life period after opening Watch out for next consumer or legislative target Isopropylparaben, isobutylparaben, phenylparaben, benzylparaben and pentylparaben now banned Maximum concentration of propylparaben and butylparaben reduced from 0.4% when used individually and 0.8% when mixed with other esters, to 0.14% when used individually or together early 2015 MCI/MI mix banned from leave-on products such as body creams July 2015 Will methylisothiazolinone be next? 8

9 The formulators frustrations Parabens work but consumer perception is that they are bad Organic acids do not work well but consumer perception is that they are good Consumer perception is that chemicals are bad and petrochemicals are even worse yet benzyl alcohol is good. Also if benzyl alcohol is part of a perfume it is a potential allergen at 0.001% yet can be used as a preservative at up to 1% Other materials that have this anomalous behaviour includes salicylic acid: listed in Annex V to be used at a maximum concentration of 0.5% as a preservative however it is permitted at 3% in rinse-off hair products and 2% in leave-on skin care with the provision that its primary purpose must not be the inhibition of micro-organisms and its purpose must be apparent from the presentation of the product! 9

10 The formulators frustrations What is good in Europe becomes bad in the USA or Japan etc. and visa versa Example: o-cymen-5-ol is closely related to thymol, which occurs naturally in many plants including thyme, where it may represent 60% of its essential oil Annex V: permitted at up to 0.1% in leave-on and wash-off products The CIR Review shows it as safe at concentrations up to 0.5% No upper limit in Japan provided the product is not intended for use on mucous membranes. Perhaps we should add 1% thyme oil to our products. Many essential oils have antimicrobial activity and suppliers are creating interesting mixtures that circumvent Annex V 10

11 Some answers Convince the consumer that preservatives protect them from potential harm Make products anhydrous Formulate the product to provide an unfriendly environment to bacteria, yeasts and moulds Use permitted preservatives Look for synergy between preservatives Use materials that coincidently have an antimicrobial action 11

12 Convince the consumer Present the facts Scientific opinions by the SCCS and CIR reports The CTPA simplifies reports and presents The Personal Care Products Council Cosmetics Europe Chemical Watch First convince the marketing department Then convince beauty editors Then educate the consumer 12

13 Make products anhydrous Lipsticks and pressed powders Seal from the environment aerosols; collapsible tubes; certain pump dispensers Powdered shampoos Non-aqueous shower gels & bath additives Solvent-based products e.g. Mascara; After-shave; Toilet Waters 13

14 Unfriendly environments: a.k.a. Hurdle technology Reduce water availability Lowering the water activity of the final composition is a possible route to avoid the use of traditional preservatives however it is rarely practical with an oil-inwater composition or with other water-based products Materials used to achieve lower water activity include glycols such as glycerin and butylene and propylene glycols Higher diols like pentylene glycol, 1,2-hexanadiol and caprylyl glycol appear to have an antimicrobial effect beyond their water-binding capacity but they also become less water-soluble Unfriendly ph Preservative-free & self-preserving cosmetics & drugs; Jon J Kabara, Donald S Orth 14

15 Use permitted preservatives (EC) No. 1223/2009 Annex V- permitted preservatives Benzoic acid and its sodium salt Glutaral 2-Bromo-2-nitropropane-1,3- diol (Bronopol) Hexamidine & salts 5-Bromo-5-nitro-1,3-dioxane Hexetidine 7-Ethylbicyclooxazolidine Imidazolidinyl urea Benzalkonium chloride, bromide etc Iodopropynyl butylcarbamate Benzethonium Chloride Kathon CG Mix Benzyl alcohol Methenamine Benzylhemiformal Methylisothiazolinone Biphenyl-2-ol, and its salts o-cymen-5-ol Bromochlorophene o-phenylphenol, sodium o-phenylphenatae etc Cetrimonium Chloride etc Parabens Chlorhexidine, Chlorhexidine diacetate p-chloro-m-cresol Chloroacetamide Phenoxyethanol Chlorobutanol Phenoxyisopropanol Chlorophene Phenylmercuric salts Chlorophene Piroctone Olamine Chloroxylenol Polyaminopropyl biguanide Chlorphenesin Propionic acid + salts Climbazole Quaternium-15 Dehydroacetic acid, sodium dehydroacetate Silver chloride Diazolidine urea Sodium Hydroxymethylglycinate Dibromohexamidine Isethionate Sorbic acid and sorbates Dichlorobenzyl Alcohol Sulfites Dimethyl Oxazolidine Thimerosal DMDM Hydantoin Triclocarban Formaldehyde, Paraformaldehyde Triclosan Formic acid, sodium formate Undecylenic acid and its salts Zinc pyrithione Annex V Simplified. 54 ingredients plus salts 15

16 Useful permitted preservatives Benzoic acid and its sodium salt 2-Bromo-2-nitropropane-1,3- diol Chlorhexidine, Chlorhexidine diacetate Chloroacetamide Chlorophene Chloroxylenol Chlorphenesin Dehydroacetic acid, Na dehydroacetate Diazolidine urea Dichlorobenzyl alcohol DMDM Hydantoin Glutaral Annex V Very Simplified. 26 ingredients plus salts Iodopropynyl butylcarbamate MIC/MI mix Methylisothiazolinone o-cymen-5-ol Parabens p-chloro-m-cresol Phenoxyethanol Phenoxyisopropanol Polyaminopropyl biguanide Quaternium-15 Silver chloride Sodium Hydroxymethylglycinate Sorbic acid and sorbates Undecylenic acid + salts 16

17 Useful permitted preservatives Benzoic acid & Na benzoate (0.5% in Leave-on) 2-Bromo-2-nitropropane-1,3- diol Iodopropynyl butylcarbamate MIC/MI Mix Chlorhexidine, Chlorhexidine diacetate Methylisothiazolinone Chloroacetamide o-cymen-5-ol Chlorophene Parabens Chloroxylenol p-chloro-m-cresol Chlorphenesin (0.3%) Phenoxyethanol (1.0%) Dehydroacetic acid, Na dehydroacetate (0.6%) Phenoxyisopropanol [Rinse-off only] Diazolidine urea Polyaminopropyl biguanide Dichlorobenzyl Alcohol (0.15%) Quaternium-15 DMDM Hydantoin Silver chloride Glutaral Sodium Hydroxymethylglycinate Imidazolidinyl urea Sorbic acid and sorbates (0.6% as acid) Undecylenic acid & salts (0.2% as acid) Annex V Very Very Simplified 17

18 COSMOS permitted preservatives Benzoic acid & its salts ph & solubility problems Benzyl alcohol Known allergen Salicylic acid & its salts ph & solubility problems Sorbic acid & its salts ph & solubility problems Dehydroacetic acid & its salts ph problems 18

19 Frequency of Use: List prepared by David Steinberg showing numbers of products containing preservatives as shown US 2007 US 2010 Canada 2008 Canada Methylparaben 25.38% 22.53% 25.71% 25.39% Propylparaben 20.40% 17.48% 22.27% 15.83% Phenoxyethanol 11.22% 14.89% 12.71% 15.83% Butylparaben 9.72% 8.87% 9.06% 9.50% Ethylparaben 8.28% 8.17% 8.02% 8.60% Isobutylparaben 3.68% 4.52% 4.23% 0.25% MI 3.08% 4.04% 2.24% 4.21% MCI/MI mix 3.04% 3.75% 1.52% 3.92% DMDM Hydantoin 3.64% 3.41% 3.22% 3.45% Imidazolidinyl urea 4.95% 3.37% 4.45% 3.72% Benzyl Alcohol 2.46% 3.34% 1.98% 2.95% Caprylyl Glycol 1.29% 2.87% 0.62% 2.07% Diazolidinyl urea 2.84% 2.76% 3.96% 4.28% 2010 Preservatives in common use in USA & Canada 19

20 Frequency of Use: List prepared by David Steinberg showing numbers of products containing preservatives as shown US 2007 US 2010 Can 2008 Cana 2010 Parabens 67.47% 61.57% 69.29% 59.57% Formaldehyde Donors 11.43% 9.54% 11.64% 11.45% Phenoxyethanol 11.22% 14.89% 12.71% 15.83% MCI + MCI/MI mix 6.12% 7.79% 3.76% 8.13% Benzyl Alcohol 2.46% 3.34% 1.98% 2.95% Caprylyl Glycol 1.29% 2.87% 0.62% 2.07% Simplified by preservative types 20

21 Trends in preservative use: USA % 14.00% Phenoxyethanol 12.00% 10.00% Formaldehyde donors 8.00% 6.00% MCI + MI + MCI 4.00% 2.00% 0.00% Benzyl alcohol Caprylyl glycol

22 Trends in preservative use in EU European skin care Benzoates 6.89% 5.77% 13.00% 13.34% 13.67% 13.59% Isothiazolines 0.00% 0.01% 0.07% 0.29% 0.26% 0.29% Parabens 63.15% 63.37% 61.43% 61.39% 61.32% 61.35% Phenoxyethanol 29.96% 30.85% 25.50% 24.98% 24.75% 24.78% 22

23 35.00% Trends in European preservative use 30.00% 25.00% Phenoxyethanol 20.00% 15.00% Benzoic acid/benzoates 10.00% 5.00% 0.00% Isothiazolines Benzoates Isothiazolines Phenoxyethanol Parabens make up the ~ 61% 23

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25 Permitted preservatives: improve effect Activity of parabens increases with the increase in alkyl chain length, however their solubility in water is inversely proportional to the length of alkyl chain Methylparaben is only soluble at 0.25% in water If oils are present its partition coefficient will favour migration into the oil phase but adding 0.02% propylparaben to the emulsion keeps methylparaben in the aqueous phase 2% propylene glycol allows the minimum inhibitory concentration of methylparaben to be reduced from 0.18% to 0.1% when combined with 0.02% propylparaben Prickett PS, Murray HL, Mercer NH. Potentiation of preservatives (parabens) in pharmaceutical formulations by low concentrations of propylene glycol. J Pharm Sci 1961; 50:

26 Permitted preservatives: improve effect Phenoxyethanol is a favoured solvent for parabens Other materials that enhance activity by promoting solubility are benzyl alcohol Ethylhexylglycerin Ethanol 1,2 Hexanediol is a solvent that enhances the preservative potency of known mild preservatives these materials plus propylene glycol frequently appear in preservative systems offered as alternatives to parabens because of their antimicrobial activity and solvent properties 26

27 Improving the effect: Phenoxyethanol Phenoxyethanol is permitted to a maximum level of 1% and has bactericidal activity across the total ph range likely to be found in cosmetics Best against Gram ve bacteria; weak activity against other microbial contaminants so it is usually found in combination with other preservatives; traditionally parabens but other mixtures are now widely available Its solubility in water is about 2.4% It is compatible with cationic and anionic surfactants but it may be inactivated by ethoxylated surfactants Increasingly popular but does not have COSMOS or Ecocert approval 27

28 Improving the effect: Benzyl alcohol Benzyl alcohol is approved as a preservative in EU at a maximum level of 1% Water soluble up to about 3g/L and is bactericidal at between 1% and 2% OK against Gram +ve; some activity against Gram ve & yeast; poor against mould Optimum ph <5; little effect above ph 7. Inactivated by non-ionics Good as solvent for parabens It is often used in perfumery as a solvent but because it is a potential irritant its presence must be indicated on the label when its concentration exceeds % in leave-on products and 0.01 % in rinse-off products The anomaly is that despite these concerns it can be used above 1% for purposes other than inhibiting the development of microorganisms but this purpose has to be apparent from the presentation of the product 28

29 Improving the effect: Ethylhexylglycerin Ethylhexylglycerin has no restrictions under current EU legislation It is a weak preservative in its own right. It works by reducing interfacial tension on the cellular walls of micro-organisms, enhancing the effect of other preservatives by increasing their penetration through the cell membrane Its HLB is approximately 7.5 and this can upset some emulsifier systems Its water solubility is about 1.8g/L but it is soluble to about 30% in propylene glycol Interestingly it has demonstrable emollient properties and is increasingly used as a multifunctional component in preservative mixtures It shows minimal dermal penetration 29

30 Use organic acids. Table by Courtesy of Inolex: CHA is caprylhydroxamic acid CHA is the only organic acid with significant antimicrobial activity at ph 7. CHA is also a powerful chelating agent for iron 30

31 Organic acids Generally the activity of organic acids is not wide spectrum and their efficacy is very ph dependent Benzoic acid is effective at a concentration of 0.1% to 0.3%, which is the limit of its solubility in water. Its pk a = 4.19 and it is ineffective in solutions with a ph above 5 Because of its insolubility in water it is often used as the very soluble sodium salt but its effectiveness may be reduced by non-ionic surfactants such as the polysorbates Widely available in mixtures with other organic acids and phenoxyethanol and/or ethylhexylglycerin and/or benzyl alcohol Sorbic acid - effective concentration of 0.05% to 0.2% that is very close to its limit of solubility so potassium sorbate is often used Sorbic acid may be used at a higher ph than benzoic acid but is said to have little antimicrobial activity above ph 6 Commonly used in mixtures 31

32 Organic acids Dehydroacetic acid is permitted to 0.60% but is almost insoluble in water ( 0.1%) however it remains effective to ph 6 Salicylic acid is permitted to 0.50% and may be used at higher levels if its primary purpose is not as a preservative e.g. Anti-acne and exfoliating products* Effective antifungal and better antimicrobial properties than benzoic acid It is soluble in water to about 0.2% effectiveness declines rapidly above ph 2 Mostly found in mixtures: *It is the opinion of the SCCNFP that those substances in Annex V, that when incorporated into cosmetic formulations for non-preservative functions, should be subjected to the same restrictions in usage levels and warnings as when used for preservative effect This opinion is widely ignored *Scientific Committee on Cosmetic Products and Non-food Products 32

33 Plugging the anti-fungal gap Iodopropynylbutyl carbamate (IPBC) is a highly effective fungicide at low usage levels from as little as 15ppm. Annex V: Rinse-off products 0.02%; Leave-on products 0.01%; APDs/DEOs % and not to be used in body lotions and body creams or for children under 3 years of age Dichlorobenzyl alcohol is described as a broad spectrum antifungal preservative with good bacteriostatic properties over a ph-range of 3 10 and is permitted in the EU to 0.15% Dehydroacetic acid and the water soluble sodium dehydroacetate are said to have high antifungal activity <ph7 Salicylic acid at ph 2 4 Caprylhydroxamic acid is said to have antifungal activity Chlorphenesin Undecylenic acid 33

34 Unlisted preservatives i.e. materials that are not classified as preservatives yet have antimicrobial activity Glyceryl monoesters are a good example and are to be found in many of the alternative systems Glyceryl caprylate; glyceryl laurate; glyceryl undecylenate Sorbitan caprylate Higher diols like pentylene glycol, 1,3-propanediol, methylpropanediol, 1,2-hexanadiol and caprylyl glycol Caprylyl Glycol provides biological synergism with moisturizing and wetting capabilities The one that got it wrong - Aqua/water, phenoxyethanol, methylparaben, sorbic acid, butylparaben, ethylparaben, propylparaben, isobutylparaben, methylchloroisothiazolinone, methylisothiazolinone 34

35 Essential oils A company in India produces mixtures of naturally occurring essential oils with preservative activity Mix 1- based on curry leaf and cinnamon leaf oils Mix 2 - based on orange, lemon grass and sesame oils Mix 3 - based on basil extract with clove bud, lemon grass and sesame oils Mix 4 - based on turmeric oil with clove bud, lemon grass and sesame oils All have applications other than for preservative use and have Ecocert approval 35

36 Biocidal botanical extracts A company in the USA produces multiple component mixtures claimed to have antimicrobial activity Mix 1: INCI: Origanum vulgare leaf extract, thymus vulgaris (thyme) extract, cinnamomum zeylancum bark extract, olea europaea (olive) leaf extract, rosmarinus officinalis (rosemary) leaf extract, mentha piperita leaf extract, lavandula angustifolia (lavender) flower extract, hydrastis canadensis (golden seal) root extract Mix 2: INCI: Origanum vulgare leaf extract, thymus vulgaris (thyme) extract, olea europaea (olive) leaf extract, rosmarinus officinalis (rosemary) leaf extract, lavandula angustifolia (lavender) flower extract, hydrastis canadensis (golden seal) root extract Mix 3: INCI: Origanum vulgare leaf extract, thymus vulgaris (thyme) extract, cinnamomum zeylancum bark extract, rosmarinus officinalis (rosemary) leaf extract, lavandula angustifolia (lavender) flower extract, hydrastis canadensis (golden seal) root extract 36

37 Natural alternatives p-anisic acid is found naturally in anise and has a strong action against yeast and mould below ph 5.5 Magnolia officinalis bark extract is not ph dependent and is effective against yeast and mould. Melaleuca alternifolia (Tea tree) leaf oil Rose oil (phenylethanol) has a mild rose-like odour Usnic aid from tree lichen (Usnea barbata) Honeysuckle (Lonicera japonica) Wasabi (Wasabia japonica) Japanese Horseradish Asparagopsis armata is a red seaweed gathered off the coast of Brittany that provides natural antimicrobial properties Expert on all things natural is Tony Dweck

38 New? Ethyl Lauroyl Arginate HCl Claimed to be a natural preservative made from lauric acid and L-arginine it is cationic in nature EU approved (V/58) Permitted to 0.4% but not to used for lip, oral and spray products Can be used to 0.8% in soap, anti-dandruff shampoos and non-spray DEOs It is available as 20% active solution and recommended use levels in skin care, hair care and wet wipes 0.5 2% Said to be broad spectrum it is water-soluble and stable at ph

39 Chelating agents Chelating agents are not preservatives but may provide a synergistic effect for the overall preservative system. They contribute to the partial solubilising of the cell membrane, which allows preservatives a pathway into the cell. EDTA and its sodium salts Citric acid, sodium citrate Etridonic acid Pentasodium triphosphate Natural chelates: Phytic acid, sodium gluconate, gluconolactone, zinc gluconate 39

40 Thank you for listening John Woodruff 40