Quaternium-73: A Versatile Antimicrobial Agent for Modern Formulations

Overview and Background of Quaternium-73

Quaternary ammonium salts have excellent antistatic, bactericidal, and antiseptic properties, and are widely used as antistatic agents and softeners in the fields of textiles, oil extraction, fibers, leather, etc. Quaternium-73 (Pyrithione) can be used for the treatment of acne, pimples, etc., and has important applications in the cosmetics field as a conditioner, bactericide, whitening agent, etc., widely used in shampoos, facial products, moisturizers, and other personal care products. This product is also used as a pharmaceutical ingredient in the medical industry to treat acne, pimples, and dermatitis.

Figure 1 Characteristics of Quaternium-73

Synthesis of Quaternium-73

Step 1) Synthesis of 2-mercapto-4-methylthiazole

In a 250ml three-neck flask, add 2-mercapto-4-methylthiazole (5.0g, 38.1mmol), iodohexane (12.9g, 57.16mmol), sodium hydroxide (1.52g, 38.1mmol), and 60ml ethanol. Heat to reflux and react for 2 hours. Spot to check for the disappearance of starting materials, then perform vacuum distillation to collect fractions at 120-140°C. Obtain 7.1g of yellow liquid with a yield of 80.3%.

Step 2) Synthesis of 2,4-dimethylthiazolium iodide

In a 100ml three-neck flask, add 2,4-dimethylthiazole (5.0g, 44.18mmol) and iodohexane (30.0g, 132.54mmol). Heat to 120°C and react for 12 hours. Cool, filter, and wash the filter cake with ethyl acetate. Obtain 11.9g of white solid with a yield of 79.4%.

Step 3) Synthesis of 3-hexyl-2-mercapto-4-methylthiazolium iodide

In a 250ml three-neck flask, add the 2-mercapto-4-methylthiazole synthesized in Step 1 (12.78g, 55.7mmol) and iodohexane (37.79g, 167.1mmol). Heat to 120°C and react for 12 hours. Obtain a brown oily substance without further treatment, which will be used directly in the next step reaction.

Step 4) Synthesis of Quaternium-73

Add 2,4-dimethylthiazolium iodide (18.9g, 55.7mmol), ethanol (100ml), and DIPEA (100ml) to the brown oily substance obtained in Step 2). Stir and reflux for 12 hours. Spot to check for the disappearance of starting materials, then stop stirring and let it cool to room temperature. Precipitate the solid, filter, and wash with ethanol. Obtain 27.3g of yellow solid with a yield of 91.0% and HPLC purity of 99.9%.

Main Components of Quaternium-73

The primary component of Quaternium-73 is the quaternary ammonium group responsible for its antimicrobial properties. This group consists of a nitrogen atom bonded to four organic groups, one typically a long-chain alkyl group. This group enhances the compound's ability to disrupt microbial cell membranes, leading to the inactivation and destruction of bacteria, fungi, and viruses.

Uses of Quaternium-73

Personal Care Products

In shampoos and conditioners, Quaternium-73 acts as a preservative and conditioning agent, maintaining product stability and effectiveness by preventing bacterial and fungal growth. It provides a conditioning effect, leaving hair smooth and manageable. In lotions and creams, Quaternium-73 enhances antimicrobial properties, making them safer for skin application, especially in formulations for sensitive or acne-prone skin.

Household and Industrial Applications

Beyond personal care products, Quaternium-73 is used in household and industrial cleaning products for its strong antimicrobial properties. It is effective in disinfectants and sanitizers, maintaining hygiene and reducing infection spread in various environments. In industrial settings, it is used in surface cleaners and disinfectants to keep machinery and equipment free of harmful microorganisms.

The Acne Removing Principle of Quaternium-73

The occurrence of acne is closely related to factors such as excessive sebum secretion, blockage of hair follicle sebaceous gland ducts, bacterial infections, and inflammatory reactions. Piaoning can also eliminate acne by inhibiting Propionibacterium acnes, and it can work at very low concentrations (0.008%). Its jurisdiction is wider than that of BPO, and it also has a strong inhibitory effect on Malassezia, a fungal fungus in the skin. Therefore, it has certain efficacy in treating fungal acne. The so-called fungal acne is indeed similar to acne, but strictly speaking, it is not acne. The usage method of Quaternium-73 is suitable for various skincare products and is recommended for use in oil control and acne removal, anti acne skincare products, and men's skincare products; Suggest pre dissolving with ethanol, butanediol, and pentanediol before adding.

Reference

[1] Becker L C. Quaternium-15[J]. International Journal of Toxicology, 2017, 36(5_suppl2): 52S-52S.

[2] Faggio C, Pagano M, Alampi R, et al. Cytotoxicity, haemolymphatic parameters, and oxidative stress following exposure to sub-lethal concentrations of quaternium-15 in Mytilus galloprovincialis[J]. Aquatic Toxicology, 2016, 180: 258-265.

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