Compendium of the most significant studies with reference to properties, intake, effects.

Almoughrabie S, Ngari C, Guillier L, Briandet R, Poulet V, Dubois-Brissonnet F. Rapid assessment and prediction of the efficiency of two preservatives against S. aureus in cosmetic products using High Content Screening-Confocal Laser Scanning Microscopy. PLoS One. 2020 Jul 27;15(7):e0236059. doi: 10.1371/journal.pone.0236059.

Abstract. Most cosmetic products are susceptible to microbiological spoilage due to contaminations that could happen during fabrication or by consumer's repetitive manipulation. The composition of cosmetic products must guarantee efficient bacterial inactivation all along with the product shelf life, which is usually assessed by challenge-tests. A challenge-test consists in inoculating specific bacteria, i.e. Staphylococcus aureus, in the formula and then investigating the bacterial log reduction over time. The main limitation of this method is relative to the time-consuming protocol, where 30 days are needed to obtain results.

Fukui GM, Berger FM, Chandlee GC, Goldenbaum EG. Effect of chlorphenesin on localized hemolysis in gel assay. J Bacteriol. 1968 Oct;96(4):1133-6. doi: 10.1128/jb.96.4.1133-1136.1968.

Abstract. Chlorphenesin, a simple glycerol ether, when added to Jerne plates greatly reduced the number of hemolytic plaques. This effect appeared to be related to dose, and was clearly demonstrable with antibody-forming spleen cells from mice that had been immunized either with sheep red blood cells or with penicillin G conjugated with Keyhole limpet hemocyanin. Chlorphenesin did not affect the antigen, destroy complement, or interfere with the interaction of complement and the antigen-antibody complexes. Incubation of spleen cell suspensions with chlorphenesin prior to plating was more effective in reducing the number of plaques than was addition of the substance to the plates. It may act by reducing the ability of antibodies to react with antigens or by affecting the release of antibodies from the spleen cells.

Whang HY, Neter E. Chlorphenesin: an antigen-associated immunosuppressant. Infect Immun. 1970 Jul;2(1):60-4. doi: 10.1128/iai.2.1.60-64.1970.

Abstract. Chlorphenesin, when injected intravenously together with either of two common bacterial antigens, inhibits the antibody response of the rabbit. The antigens studied are those common to Enterobacteriaceae and to gram-positive bacteria.

Ben Ouaghrem M, de Vaugelade S, Bourcier S, Genty C, Pirnay S, Bouchonnet S. Characterization of photoproducts and global ecotoxicity of chlorphenesin: A preservative used in skin care products. Int J Cosmet Sci. 2021 Dec 27. doi: 10.1111/ics.12760.

Abstract. Photolysis experiments of chlorphenesin, used as a preservative in cosmetic products, were performed in aqueous solution and on a cream used in cosmetics. © 2022 Society of Cosmetic Scientists and Societe Francaise de Cosmetologie.

Chlorphenesin (3-p-chlorophenoxy-1,2-propanediol) is a chemical compound, phenolic ether, derived from glycerol and belongs to the class of organic organohalogen compounds. Halogenation is an antibacterial process.

Chemical Industrial Synthesis Process

• Preparation of reagents. The main reagents include p-chlorophenol and glycerin, which are the raw materials needed for the synthesis of Chlorphenesin.
• Esterification reaction. Glycerin and p-chlorophenol are combined in the presence of a dehydrating agent, such as sulfuric acid, to facilitate ester formation.
• Monitoring the reaction. The reaction is closely monitored to ensure it proceeds under optimal temperature and time parameters, thus maximizing the product yield.
• Purification. The crude product is purified through techniques such as distillation or crystallization to remove impurities and enhance the purity of Chlorphenesin.
• Quality control. The purified Chlorphenesin undergoes various chemical and microbiological tests to verify its purity, efficacy, and safety.

It appears in the form of a white powder

A cosa serve e dove si usa

Antibacterial and antifungal agent (active against Gram-positive and Gram-negative bacteria). The maximum allowable dosage is 0.3 percent in rinsing products. (1).

Chlorphenesin is inserted in cosmetic formulations for its effectiveness in protecting products from microbial contamination. This preservative not only extends the product's shelf life but also ensures safety in use by preventing the growth of harmful microorganisms. It is commonly used in a wide range of cosmetic products, including creams, lotions, and skincare products, where it helps maintain the integrity and quality of the product over time.

Cosmetics

It is a restricted cosmetic ingredient as V/50  a Relevant Item in the Annexes of the European Cosmetics Regulation 1223/2009. Substance or ingredient reported: 3-(p-Chlorophenoxy)-propane-1,2-diol. Maximum concentration in ready for use preparation    0.3%

Cosmetics - INCI Functions

• Antimicrobial agent. This ingredient is able to suppress or inhibit the growth and replication of a broad spectrum of microorganisms such as bacteria, fungi and viruses by making the stratum corneum temporarily bactericidal and fungicidal.
• Preservative. Any product containing organic, inorganic compounds, water, needs to be preserved from microbial contamination. Preservatives act against the development of harmful microorganisms and against oxidation of the product.

Safety

Scientific literature warns about general and specific contraindications involving the application of this preservative. Specifically, with regard to the eyes, this 2020 study by Jingyi Wang and others at Harvard University warns about the toxicity of Chlorphenesin to the epithelial cells of the Meibomian gland, which secretes, through its ducts, the human tear film, a major source of lipid (2).

Chlorphenesin studies

Appearance	White fine powder
Boiling Point	369.5±27.0 °C at 760 mmHg
Melting Point	77-79°C
Density	1.3±0.1 g/cm3
Flash Point	177.2±23.7°C
Index of Refraction	1.565
Vapour Pressure	0.0±0.9 mmHg at 25°C
LogP	1.43
PSA	49.69000
Safety

• Formula molecolare  C₉H₁₁ClO₃
• Peso molecolare     202.63
• Massa esatta   202.039673
• CAS  104-29-0
• UNII    I670DAL4SZ
• EC Number   203-192-6
• DSSTox Substance ID  DTXSID0049028
• IUPAC  3-(4-chlorophenoxy)propane-1,2-diol
• InChI=1S/C9H11ClO3/c10-7-1-3-9(4-2-7)13-6-8(12)5-11/h1-4,8,11-12H,5-6H2  
• InChl Key      MXOAEAUPQDYUQM-UHFFFAOYSA-N
• SMILES   C1=CC(=CC=C1OCC(CO)O)Cl
• MDL number  
• PubChem Substance ID    
• ChEBI  3642
• NSC   6401
• RTECS   TY4260000

Synonyms:

• 3-(4-chlorophenoxy)propane-1,2-diol
• p-Chlorophenyl glyceryl ether

References___________________________________________________________________

(1) Johnson W Jr, Bergfeld WF, Belsito DV, Hill RA, Klaassen CD, Liebler DC, Marks JG Jr, Shank RC, Slaga TJ, Snyder PW, Andersen FA. Safety Assessment of Chlorphenesin as Used in Cosmetics. Int J Toxicol. 2014 May;33(2 suppl):5S-15S. doi: 10.1177/1091581814526893.

(2) Wang J, Liu Y, Kam WR, Li Y, Sullivan DA. Toxicity of the cosmetic preservatives parabens, phenoxyethanol and chlorphenesin on human meibomian gland epithelial cells. Exp Eye Res. 2020 Jul;196:108057. doi: 10.1016/j.exer.2020.108057.