Stearamidopropyl Dimethicone is a modified silicone derived from dimethicone, to which a stearamidopropyl group has been added. This compound is known for its conditioning and film-forming properties and is primarily used in cosmetics and personal care products to enhance texture and sensory experience.
Chemical Composition and Structure
Chemical Composition: It consists of a dimethicone base structure with an added stearamidopropyl group. This chemical modification imparts unique properties, including better oil compatibility and reduced stickiness.
Structure: The chemical structure includes a siloxane (Si-O) chain attached to a stearamidopropyl group, which consists of a stearamide and a propyl group. This gives the compound its conditioning and texturizing characteristics.
Physical Properties
- Appearance: Typically a clear, colorless or slightly yellowish liquid.
- Solubility: Slightly soluble in water but soluble in oils and organic solvents. Forms a protective film on skin and hair.
- pH: Stable across a broad pH range, making it suitable for various cosmetic formulations.
Production Process
- Silane Modification: The base dimethicone is modified with stearamidopropyl groups.
- Polymerization: Siloxane chains are polymerized to incorporate stearamidopropyl groups.
- Purification: The product is purified to ensure the absence of impurities and safety for use.
- Incorporation: Added to cosmetic and personal care products to enhance texture and conditioning properties.
Applications
- Medical: Not commonly used in medical applications.
- Cosmetics: Used in hair and skin products to improve sensory feel and texture. Acts as a conditioning agent and film-former, reducing frizz and improving hair manageability. Can also be used in lotions and creams to enhance spreadability and comfort.
INCI Functions:
Film-forming agent. It produces a continuous ultra-thin film with an optimal balance of cohesion, adhesion and stickiness on the skin or hair to counteract or limit damage from external phenomena such as chemicals, UV rays and pollution.
Corrosion inhibitor. It is added to the formulation to prevent, delay or reduce the rate of corrosion and also to decrease the spread of corrosion rates. Performance depends on exposure time.
CAS: 227200-31-9
- Food: Not used in food products.
Environmental and Safety Considerations
Generally regarded as safe for topical application (1). However, like all silicones, it should be used in accordance with established guidelines to avoid potential allergic reactions or skin irritations. Individuals with sensitive skin or allergies should exercise caution. It is important to ensure that the product is sustainably sourced and free from harmful chemicals.
References__________________________________________________________________________
(1) Nair B; Cosmetic Ingredients Review Expert Panel. Final report on the safety assessment of stearoxy dimethicone, dimethicone, methicone, amino bispropyl dimethicone, aminopropyl dimethicone, amodimethicone, amodimethicone hydroxystearate, behenoxy dimethicone, C24-28 alkyl methicone, C30-45 alkyl methicone, C30-45 alkyl dimethicone, cetearyl methicone, cetyl dimethicone, dimethoxysilyl ethylenediaminopropyl dimethicone, hexyl methicone, hydroxypropyldimethicone, stearamidopropyl dimethicone, stearyl dimethicone, stearyl methicone, and vinyldimethicone. Int J Toxicol. 2003;22 Suppl 2:11-35. PMID: 14555417.
Abstract. Dimethicone is a fluid mixture of fully methylated linear siloxane polymers end-blocked with trimethylsiloxy units. Methicone is a linear monomethyl polysiloxane. The other dimethicones and methicones covered in this review are siloxane polymers of Dimethicone and Methicone. Most of these ingredients function as conditioning agents in cosmetic formulations at current concentrations of use of < or =15%. Clinical and animal absorption studies reported that Dimethicone was not absorbed following oral or dermal exposure. Dimethicone, Methicone, and Vinyldimethicone were not acutely toxic following oral exposure. No adverse reactions were found in rabbits following short-term dermal dosing with 6% to 79% Dimethicone, yet adverse effects were noted with a hand cream formulation containing 1% Dimethicone, suggesting something else in the preparation was toxic. Mice and rats were dosed for 90 days with up to 10% Dimethicone without adverse effect. Dimethicone did not produce adverse effects in acute and short-term inhalation-route studies, Methicone and Vinyldimethicone were negative in acute exposure studies using rats, but Hexyl Methicone was toxic to rats at 5 mg/L delivered in small particle (mean diameter of 0.29 micro) aerosols. Most dermal irritation studies using rabbits classified Dimethicone as a minimal irritant. Dimethicone (tested undiluted and at 79%) was not a sensitizer in four assays using mice and guinea pigs. It was not a sensitizer at 5.0% in a clinical repeated insult patch test using 83 panelists. Most ocular irritation studies using rabbits classified Dimethicone as a mild to minimal irritant. Dimethicone was tested in numerous oral-dose (using rats) and dermal-dose (using rats, rabbits, and monkeys) reproductive and developmental toxicity studies. In a few studies, treated males had significantly decreased body weight and/or decreased testes or seminal vesicles weights. No treatment-related adverse findings were noted in dosed pregnant females or fetuses. Dimethicone was negative in all genotoxicity assays. It was negative in both an oral (tested at 91%) and dermal (tested at an unknown concentration) dose carcinogenicity assay using mice. The Cosmetic Ingredient Review (CIR) Expert Panel considered it unlikely that any of these polymers would be significantly absorbed into the skin due to their large molecular weight. Although adverse effects were noted in one inhalation study with small aerosol particles, the expected particle sizes for cosmetic products would primarily be in the range of 60 to 80 micro, and less than 1% would be under 10 micro, which is an upper limit for respirable particles. Overall, the safety test data support the safety of these ingredients at the concentrations they are known to be used in cosmetic formulations. Accordingly, the CIR Expert Panel was of the opinion that Stearoxy Dimethicone, Dimethicone, Methicone, Amino Bispropyl Dimethicone, Aminopropyl Dimethicone, Amodimethicone, Amodimethicone Hydroxystearate, Behenoxy Dimethicone, C24-28 Alkyl Methicone, C30-45 Alkyl Methicone, C30-45 Alkyl Dimethicone, Cetearyl Methicone, Cetyl Dimethicone, Dimethoxysilyl Ethylenediaminopropyl Dimethicone, Hexyl Methicone, Hydroxypropyldimethicone, Stearamidopropyl Dimethicone, Stearyl Dimethicone, Stearyl Methicone, and Vinyldimethicone are safe as used in cosmetic formulations.
