Zinc Citrate, Trizinc Dihydrate, Trizinc Trihydrate, 546-46-3

Zinc Citrate (C₁₂H₁₀O₁₄Zn₃)

1. General Information

• Molecular Formula: C₁₂H₁₀O₁₄Zn₃

• Molecular Weight: 574.37 g/mol

• CAS Number: 546-46-3

• Chemical Name: Zinc Citrate

• Synonyms:

  • Citric Acid Zinc Salt

  • Trizinc; 2-hydroxypropane-1,2,3-tricarboxylate

  • Trizinc Dihydrate / Trihydrate

2. Chemical and Physical Properties

• Appearance: White crystalline powder.

• Hydration Forms: Exists as dihydrate (2H₂O) and trihydrate (3H₂O).

• Zinc Content: Up to 31% under optimized production conditions, making it one of the highest zinc-containing compounds used in supplements.

• Solubility:

  • Poorly soluble in water.

  • Soluble in dilute mineral acids (e.g., sulfuric acid).

  • Soluble in alkaline hydroxide solutions such as calcium hydroxide and magnesium hydroxide.

• Melting/Boiling Point: Not well established due to decomposition before reaching a clear melting point.

3. Biological Importance

• Essential Trace Element: Zinc is vital for numerous biological processes but cannot be synthesized by the human body.

• Immune System Support:

  • Enhances T-cell activation and immune response.

  • Plays a role in wound healing and skin integrity.

• Metabolic Functions:

  • Required for DNA/RNA synthesis and cell division.

  • Supports bone health, fertility, and reproductive functions.

• Zinc Loss: Excessive sweating leads to zinc depletion, making supplementation important for athletes and individuals with high physical activity.

• Skin Reservoir: The skin contains the highest concentration of zinc in the human body, highlighting its role in dermatological health.

4. Applications

• Dietary Supplements:

  • Used in tablets and capsules as a zinc source.

  • High zinc content makes it suitable for strong supplementation formulas.

• Pharmaceuticals:

  • Incorporated into throat lozenges and gargles for sore throat relief.

  • Utilized in anti-inflammatory formulations to strengthen immunity against cold weather conditions.

• Oral Care:

  • Added to mouthwashes and toothpastes as a plaque-preventive agent.

  • Provides antibacterial activity in oral hygiene products.

• Cosmetics:

  • Functions as an antibacterial agent in creams and lotions.

  • Supports skin health and healing.

5. Comparative Notes

• Zinc Citrate: High zinc content, lower solubility.

• Zinc Gluconate: Better solubility, faster absorption, often preferred in lozenges.

• Zinc Oxide: Very low solubility but stable, used in topical and long shelf-life formulations.

6. Production and Quality

• Manufacturing: Produced by neutralizing citric acid with zinc oxide or zinc carbonate under controlled conditions.

• Quality Control:

  • Zinc content measured via titration or ICP-MS.

  • Hydration state determined by XRD or TGA.

• Regulatory Compliance: Approved for use in dietary supplements and cosmetics under FDA, EFSA, and Turkish Food Codex standards.

7. Summary

Zinc Citrate is a highly valuable compound in the nutraceutical, pharmaceutical, oral care, and cosmetic industries. Its high zinc content (up to 31%), combined with its role in immune support, bone health, fertility, and skin care, makes it a versatile raw material. Despite its lower solubility compared to other zinc salts, it remains a preferred choice in formulations where zinc concentration is prioritized over rapid dissolution.