Starch Hydroxypropyltrimonium Chloride is the quaternary ammonium compound formed by the reaction of starch with 2,3-epoxypropyltrimethylammonium chloride, a non-GMO, naturally derived, non-ethoxylated cationic starch polymer with a low viscosity. Derived from food-grade potato starch, it contains no GMOs, phthalates, dioxin, BSE-related materials, CMR (carcinogenic, mutagenic or reproductive toxicity) substances.

The name defines the structure of the molecule:

• Starch is the basic molecule that is modified. Starch is a polysaccharide, which means that it is a large molecule composed of many sugar units.
• Hydroxypropyl. This indicates that a hydroxypropyl group (-CH2CH(OH)CH3) has been added to the starch molecule through a process called etherification, which involves replacing a hydrogen atom of the hydroxyl (-OH) group in the starch molecule with the hydroxypropyl group.
• Trimonium Chloride indicates that the starch molecule has been modified by adding a trimonium chloride group. The "trimonium" part means that there are three methyl groups (-CH3) attached to a nitrogen atom, and the "chloride" part indicates that there is a chloride ion associated with the molecule, giving it a positive charge. This makes the molecule a type of quaternary ammonium compound often used for their antimicrobial properties.

The synthesis process takes place in several stages:

• Extraction of starch from vegetable sources such as corn, potatoes or wheat with starch separation from the rest of the plant material, usually through a grinding and washing process.
• Modification of starch chemically to introduce hydroxypropyl groups through a reaction with propylene oxide.
• Quaternization. Reaction with a quaternary ammonium compound, such as trimethylammonium chloride, to introduce the quaternary ammonium group into an aqueous solution and may require the use of a catalyst.
• Purification. Starch Hydroxypropyltrimonium Chloride is typically purified with a filtration and drying treatment.

It appears in the form of a viscous gel.

What it is used for and where

Cosmetics

Used in hair care as a conditioning agent to make hair smooth and increase its volume with a soft foaming effect. Also suitable on the skin. Used in shampoos, conditioners and hair lotions, skin care products, liquid soaps, creams, lotions and cleansers for the face and body. Compared to Poliquaternium 7 or Poliquaternium 10 it shows a softer effect on both hair and skin.

Antistatic agent. Static electricity build-up has a direct influence on products and causes electrostatic adsorption. The antistatic ingredient reduces static build-up and surface resistivity on the surface of the skin and hair.

Emulsion stabilizer. Emulsions are thermodynamically unstable. Emulsion stabilisers improve the formation and stability of single and double emulsions. It should be noted that in the structure-function relationship, molar mass plays an important role.

Hair conditioning agent. A significant number of ingredients with specific and targeted purposes may co-exist in hair shampoo formulations: cleansers, conditioners, thickeners, matting agents, sequestering agents, fragrances, preservatives, special additives. However, the indispensable ingredients are the cleansers and conditioners as they are necessary and sufficient for hair cleansing and manageability. The others act as commercial and non-essential auxiliaries such as: appearance, fragrance, colouring, etc. Hair conditioning agents have the task of increasing shine, manageability and volume, and reducing static electricity, especially after treatments such as colouring, ironing, waving, drying and brushing. They are, in practice, dispersants that may contain cationic surfactants, thickeners, emollients, polymers. The typology of hair conditioning agents includes: intensive conditioners, instant conditioners, thickening conditioners, drying conditioners. They can perform their task generally accompanied by other different ingredients.

Viscosity control agent. It controls and adapts viscosity to the required level for optimal chemical and physical stability of the product and dosage in gels, suspensions, emulsions, solutions. 

Dosage:

Typical characteristics of a commercial hair shampoo product:

The most relevant studies on this ingredient have been selected with a summary of their contents:

Starch Hydroxypropyltrimonium Chloride studies

CAS     56780-58-6

Synonyms:

• Starch, 2-hydroxy-3-(trimethylammonio)propyl ether, chloride
• (3-Chloro-2-hydroxypropyl)trimethylammoniumchloridemodifiedstarch
• Starch,N,N,N-trimethyl-2-hydroxypropanaminiumchlorideether

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

Belsito, M. D., Hill, R. A., Klaassen, C. D., Liebler, D. C., & Marks Jr, J. G. (2014). Safety assessment of plant polysaccharide gums as used in cosmetics. Cosmet. Ingredient Rev, 1-45.

Abstract. According to information supplied to the FDA by industry as part of the VCRP and results from a Council survey of  ingredient use concentrations, the following 57 plant polysaccharide gums are being used in cosmetic products: maltodextrin, agar, agarose, algin, alginic acid, amylodextrin, avena sativa (oat) starch, calcium alginate, carrageenan, cassia angustifolia seed polysaccharide, cichorium intybus (chicory) root oligosaccharides, corn starch modified, croscarmellose, cyclodextrin, cyclodextrin laurate, dextrin, dextrin myristate, dextrin palmitate, dextrin palmitate/stearate, galactoarabinan, glycerol alginate, glyceryl starch, hydrogenated starch hydrolysate, hydrolyzed corn starch octenylsuccinate, hydrolyzed pectin, hydrolyzed starch, hydrolyzed wheat starch, hydroxypropyltrimonium hydrolyzed corn starch, hydroxyethyl cyclodextrin, hydroxypropyl cyclodextrin, hydroxypropyltrimonium hydrolyzed wheat starch, hydroxypropyltrimonium maltodextrin crosspolymer, hydroxypropyl starch, inulin, laurdimonium hydroxypropyl hydrolyzed wheat starch, mannan, methyl cyclodextrin, natto gum, pectin, polianthes tuberosa polysaccharide, potassium alginate, potato starch modified, propylene glycol alginate, pueraria lobata starch, sodium carboxymethyl starch, sodium carrageenan, sodium hydrolyzed potato starch dodecenylsuccinate, sodium oxidized starch acetate/succinate, sodium starch octenylsuccinate, solanum tuberosum (potato) starch, starch acetate, starch diethylaminoethyl ether, starch hydroxypropyltrimonium chloride, stearoyl inulin, sterculia urens gum, tamarindus indica seed gum, tapioca starch, and triticum vulgare (wheat) starch.

Kaur, T., Singh, R.P. (2020). Carbohydrate Biopolymers: Diversity, Applications, and Challenges. In: Singh, J., Meshram, V., Gupta, M. (eds) Bioactive Natural products in Drug Discovery. Springer, Singapore. https://doi.org/10.1007/978-981-15-1394-7_18

Abstract. Biopolymers are a chemically diverse and functionally versatile group of natural products produced by all living organisms. Many of these biopolymers and their derivatives have found commercial applications ranging from the food to pharmaceutical industry. In the recent years, there has been an increase in the commercial usability of these versatile, yet robust scaffolds. The chapter focuses on the diversity of molecular structure and composition of polysaccharide biopolymers produced by microorganisms, plants, and animals with special emphasis on polysaccharides with commercial applications. The utility of these biopolymers and their derivatives ranges from bioremediation to biosensors, drug delivery vehicles to potential therapeutic agents, fuel cells to prosthetics, etc. These biopolymers and their derivatives are either used alone (e.g., starch or carboxymethyl cellulose) or in combination with other constituents. Recently, these biopolymers have also been investigated as fillers or active constituents in development of composites. The chapter introduces the diverse applications of these macromolecules with examples and concludes with the potential challenges faced by this group of biomolecules that deter their commercial viability, viz., cost of production, reproducibility of biopolymer characteristics, and safety and regulatory concerns.

Camargo Jr, F. B., Minami, M. M., Rossan, M. R., Magalhães, W. V., Porto Ferreira, V. T., & Maia Campos, P. M. B. G. (2022). Prevention of chemically induced hair damage by means of treatment based on proteins and polysaccharides. Journal of Cosmetic Dermatology, 21(2), 827-835.

Abstract. Background There is currently a great interest not only in developing products for the protection and recovery of chemically damaged hair, but also in developing effective protocols to investigate the impact of chemical treatments and attest the efficacy of innovative hair care products. Among the most relevant cosmetic treatments for hair are bleaching and coloring, which have been shown to significantly impair mechanical and structural properties. Objectives This study aimed to characterize the damage induced by hair bleaching and coloring and to evaluate the protective effects of a hair care treatment based on integral silk proteins (fibroin and sericin) and vegetable-derived polysaccharides from linseed (Linum usitatissimum L.).....Conclusions The proposed product was effective in protecting and repairing bleached and colored swatches, improving resistance and luster and reducing structural damage. By applying complementary techniques within a reliable evaluation protocol, it was possible to attest the protective properties of the product under study.