カルシウム/3-ヒドロキシ-3,4-ジカルボキシブタノアート,(3:2)

定義

本品は、クエン酸(*)のカルシウム塩である。参照表示名称：クエン酸

化粧品の成分用途

pH調整剤

説明

Calcium citrate is the calcium salt of citric acid. It is commonly used as a food additive (E333), usually as a preservative, but sometimes for flavor. In this sense, it is similar to sodium citrate. Calcium citrate is also used as a water softener because the citrate ions can chelate unwanted metal ions. Calcium citrate is also found in some dietary calcium supplements (e.g. Citracal). Calcium makes up 21% of calcium citrate by weight.

化学的特性

white powder or white to colourless crystals

調製方法

Calcium citrate is an intermediate in the isolation of citric acid from the fermentation process by which citric acid is produced industrially. The citric acid in the broth solution is neutralized by calcium hydroxide, precipitating insoluble calcium citrate. This is then filtered off from the rest of the broth and washed to give clean calcium citrate.
The calcium citrate thus produced may be sold as-is, or it may be converted to citric acid using dilute sulfuric acid.

応用例（製薬）

Calcium citrate is more easily absorbed (bioavailability is 2.5 times higher than calcium carbonate); it is easier to digest and less likely to cause constipation and gas than calcium carbonate. Calcium citrate can be taken without food and is more easily absorbed than calcium carbonate on an empty stomach. It is also believed that it contributes less to the formation of kidney stones. Calcium citrate consists of around 24% Ca²⁺, which means that 1000 mg calcium citrate contains around 240 mg Ca²⁺. The lower Ca²⁺ content together with the higher price makes it a more expensive treatment option compared to calcium carbonate, but its slightly different application field can justify this.

生物活性

In many individuals, bioavailability of calcium citrate is found to be equal to that of the cheaper calcium carbonate.However, alterations to the digestive tract may change how calcium is digested and absorbed. Unlike calcium carbonate, which is basic and neutralizes stomach acid, calcium citrate has no effect on stomach acid. Individuals who are sensitive to antacids or who have difficulty producing adequate stomach acid should choose calcium citrate over calcium carbonate for supplementation. According to recent research into calcium absorption after gastric bypass surgery , calcium citrate may have improved bioavailability over calcium carbonate in Rouxen- Y gastric bypass patients who are taking calcium citrate as a dietary supplement after surgery. This is mainly due to the changes related to where calcium absorption occurs in the digestive tract of these individuals.