Triethyl Citrate

Basic Information

Name: Triethyl Citrate

CAS No: 2-Hydroxy-1,2,3-propanetricarboxylic acid triethyl ester [77-93-0]

Functional Categories

Plasticizer Solvent

1. Nonproprietary Names

BP: Triethyl Citrate PhEur: Triethyl Citrate USP-NF: Triethyl Citrate

2. Synonyms

Citric acid ethyl ester; Citroflex 2; Citrofol AI; E1505; ethyl citrate; Hydagen CAT; 1,2,3-propanetricarboxylic acid, 2-hydroxy-, triethyl ester (9CI); TEC; triethylis citras.

3. Chemical Name & CAS Registry

2-Hydroxy-1,2,3-propanetricarboxylic acid triethyl ester [77-93-0]

4. Empirical Formula & Molecular Weight

C12H20O7 276.29

5. Structural Formula

6. Applications

Triethyl citrate and the related esters acetyltriethyl citrate, tributyl citrate, and acetyltributyl citrate are used to plasticize polymers in formulated pharmaceutical coatings.(1–5) The coating applications include capsules, tablets, beads, and granules for taste masking, immediate release, sustained-release, and enteric formulations. Triethyl citrate is also used as a direct food additive for flavoring, for solvency, and as a surface active agent.

7. Description

Triethyl citrate is a clear, viscous, odorless, and practically colorless, hygroscopic liquid.

8. Pharmacopeial Specifications

See Table I.

9. Typical Properties

Acid value 0.02 Boiling point 2948C Flash point 1558C Pour point 458C Solubility Soluble 1 in 125 of peanut oil, 1 in 15 of water. Miscible with ethanol (95%), acetone, and propan-2-ol. Viscosity (dynamic) 35.2 mPa s (35.2 cP) at 258C

10. Stability & Storage

Triethyl citrate should be stored in a closed container in a cool, dry location. When stored in accordance with these conditions, triethyl citrate is a stable product.

11. Incompatibilities

Triethyl citrate is incompatible with strong alkalis and oxidizing materials.

12. Method of Manufacture

Triethyl citrate is prepared by the esterification of citric acid and ethanol in the presence of a catalyst.

13. Safety

Triethyl citrate is used in oral pharmaceutical formulations and as a direct food additive. It is generally regarded as a nontoxic and nonirritant material. However, ingestion of large quantities may be harmful. LD50 (mouse, IP): 1.75 g/kg(6) LD50 (rat, IP): 4 g/kg LD50 (rat, oral): 5.9 g/kg LD50 (rat, SC): 6.6 g/kg

14. Handling Precautions

Observe normal precautions appropriate to the circumstances and quantity of material handled. Triethyl citrate is irritating to the eyes and may irritate the skin. It is irritating to the respiratory system as a mist or at elevated temperatures. Gloves, eye protection, and a respirator are recommended.

15. Regulatory Status

GRAS listed. Accepted for use as a food additive in Europe. Included in the FDA Inactive Ingredients Database (oral capsules and tablets). Included in the Canadian List of Acceptable Nonmedicinal Ingredients.

16. Related Substances

Acetyltributyl citrate; acetyltriethyl citrate; tributyl citrate.

17. Comments

A specification for triethyl citrate is contained in the Food Chemicals Codex (FCC).(7) The EINECS number for triethyl citrate is 201-070-7. The PubChem Compound ID (CID) for triethyl citrate is 6506.