Barium sulfate (CI 77120) is an inorganic compound used in various industries, including cosmetics and personal care products. In cosmetics, it functions primarily as a pigment and a bulking agent, providing opacity and a white color to formulations.

Chemical Composition and Structure: Barium sulfate (BaSO₄) is composed of:

• Barium Ion (Ba²⁺): A metal ion that is the key component of the compound.
• Sulfate Ion (SO₄²⁻): An anion consisting of a central sulfur atom surrounded by four oxygen atoms.

The chemical structure features a barium atom bonded to a sulfate group, forming a crystalline solid with a high density.

Physical Properties:

• Appearance: White, odorless powder.
• Density: High density, typically around 4.5 g/cm³.
• Solubility: Insoluble in water and most organic solvents, making it stable in various formulations.
• Texture: Fine, powdery texture.

Production Process: The production of barium sulfate involves:

• Mining: Barium sulfate is extracted from natural mineral sources, such as barite ore.
• Processing: The ore is crushed and purified to obtain pure barium sulfate. This may involve chemical treatments to remove impurities.
• Milling: The purified barium sulfate is ground into a fine powder suitable for use in cosmetic formulations.

Applications:

• Medical. Barium sulfate is used in medicine for imaging the gastrointestinal tract and usually does not settle within the wall of the intestine (1).
• Cosmetics: Used in various cosmetic products, including:
  • Foundations and Powders: Provides opacity and a white color, improving coverage and texture.
  • Sunscreens: Acts as a physical sunscreen agent by blocking UV radiation.
  • Eye Products: Adds brightness and improves the consistency of formulations.
• Personal Care Products: Can be used in products such as body lotions and creams for its bulking and stabilizing properties.
• Cosmetic Functions:

Colorant. This ingredient has the function of colouring the solution in which it is inserted in a temporary, semi-permanent or permanent manner, either alone or in the presence of the complementary components added for colouring.

Environmental and Safety Considerations:

• Environmental Impact: The extraction and processing of barium sulfate should be managed to minimize environmental disruption. Responsible mining practices are essential to reduce ecological impact.
• Safety: Barium sulfate is generally considered safe for use in cosmetics and personal care products when used as directed. It is non-toxic and non-reactive under normal conditions. However, inhalation of the powder should be avoided to prevent respiratory irritation.

Molecular Formula   BaO₄S

Molecular Weight    233.39 g/mol

CAS   7727-43-7

UNII   25BB7EKE2E

EC number   231-784-4

MFCD00003455

Synonyms: 

Pigment White 21

References____________________________________________________________________________

(1) Zaccarini DJ, Lubin D, Sanyal S, Abraham JL. Barium Sulfate Deposition in the Gastrointestinal Tract: Review of the literature. Diagn Pathol. 2022 Dec 31;17(1):99. doi: 10.1186/s13000-022-01283-8. PMID: 36585714; PMCID: PMC9805050.

Molina RM, Konduru NV, Queiroz PM, Figueroa B, Fu D, Ma-Hock L, Groeters S, Schaudien D, Brain JD. Fate of Barium Sulfate Nanoparticles Deposited in the Lungs of Rats. Sci Rep. 2019 Jun 3;9(1):8163. doi: 10.1038/s41598-019-44551-2. 

Abstract. We have shown that barium [from BaSO4 nanoparticles (NPs)] was cleared from the lungs faster than other poorly soluble NPs and translocated mostly to bone. We now studied barium biokinetics in rats during Study 1: two-year inhalation exposure to 50 mg/m3 BaSO4 NP aerosols, and Study 2: single intratracheal (IT) instillation of increasing doses of BaSO4 NPs or BaCl2. Study 1 showed that lung barium content measured by inductively coupled plasma mass spectrometry increased during 360 days of BaSO4 NP aerosol exposures. An equilibrium was established from that time until 2 years. Barium concentrations in BaSO4-exposed animals were in the order (lungs > lymph nodes > hard bone > bone marrow > liver). In Study 2, there was an increase in lung barium post-IT instillation of BaSO4 NPs while barium from BaCl2 was mostly cleared by day 28. Transmission electron microscopy showed intact BaSO4 NPs in alveolar macrophages and type II epithelial cells, and in tracheobronchial lymph nodes. Using stimulated Raman scattering microscopy, specific BaSO4 Raman spectra were detected in BaSO4 NP-instilled lungs and not in other organs. Thus, we posit that barium from BaSO4 NPs translocates from the lungs mainly after dissolution. Barium ions are then incorporated mostly into the bone and other organs.