Calcium citrate is a white, odorless, crystalline powder or granules with a slightly bitter taste. It is sparingly soluble in water and freely soluble in dilute acids. It is commonly used as a calcium supplement and as a pharmaceutical excipient in tablet and capsule formulations.
Chemical Name and CAS Registry Number: Calcium 2-hydroxypropane-1,2,3-tricarboxylate [813-94-5]
Functional Category: Alkalizing agent; buffering agent; calcium source; sequestrant.
| Test | JP | PhEur | USP |
|---|---|---|---|
| Identification | ✓ | ✓ | ✓ |
| Appearance | ✓ | ✓ | ✓ |
| pH (10% solution) | — | 5.0–9.0 | — |
| Water Content | ≤ 13.3% | 10.0–13.3% | 10.0–13.3% |
| Heavy Metals | ≤ 10 ppm | ≤ 10 ppm | ≤ 0.002% |
| Oxalate | ✓ | — | ✓ |
| Sulfate | ≤ 0.2% | ≤ 0.2% | — |
| Assay (anhydrous basis) | 97.5–100.5% | 97.5–100.5% | 97.5–100.5% |
Calcium citrate is highly bioavailable and is better absorbed than calcium carbonate, especially in individuals with low stomach acid. It is a GRAS listed ingredient and widely used in pharmaceuticals and food products.
