From the Guidelines
EDTA (ethylenediaminetetraacetic acid) effectively chelates calcium, forming stable complexes that can be removed from the body. This property is utilized in medical applications, including the treatment of band keratopathy, where EDTA is used to dissolve calcium deposits on the cornea 1. The chelation process occurs due to EDTA's multiple binding sites, which surround metal ions like calcium, creating a stable complex that prevents calcium from interacting with other molecules in the body.
In the context of band keratopathy, disodium EDTA is applied topically to the affected area, typically in a 3% to 4% solution, to facilitate the removal of calcium deposits 1. The treatment time and concentration of EDTA may vary depending on the density of the calcium and the approach used 1. It is essential to note that the use of EDTA in this context can result in delayed healing, with a mean time to healing of 5-7 days compared to 2-3 days in normal eyes with similar-sized corneal abrasions 1.
The effectiveness of EDTA in chelating calcium is well-documented, and its use in medical applications is supported by recent studies, including a 2024 study published in the journal Ophthalmology 1. This study highlights the importance of EDTA in the treatment of band keratopathy and provides guidance on its use in clinical settings.
Key points to consider when using EDTA to chelate calcium include:
- The concentration and treatment time of EDTA may vary depending on the specific application and the density of the calcium deposits 1
- EDTA can be used topically or intravenously, depending on the medical application 1
- The use of EDTA can result in delayed healing, and adjunctive techniques may be necessary to facilitate re-epithelialization in some cases 1
From the Research
EDTA and Calcium Chelation
- EDTA is a chelating agent that binds to metals, including calcium, and enables their elimination 2.
- Studies have shown that EDTA can increase the urinary excretion of calcium, indicating its ability to chelate calcium ions 3, 4.
- The chelation of calcium by EDTA can lead to a state of negative calcium balance, which can affect calcium homeostasis 4.
Mechanism of Calcium Chelation
- EDTA binds to calcium ions, forming soluble complexes that are excreted through urine 2, 4.
- The affinity of EDTA for calcium ions depends on the levels of unbound hydrated calcium ions ('free' ions) 3.
- EDTA can remove calcium from calcified tissues, including hydroxyapatite powder and calcified porcine aortic elastin 5.
Effects of EDTA on Calcium Homeostasis
- EDTA infusion can affect calcium homeostasis, leading to increased resistance to challenge 4.
- The use of EDTA can mimic the principle of lowering dietary calcium in preventing milk fever 4.
- Calcium homeostatic mechanisms respond to EDTA-induced hypocalcaemia through the effect of parathyroid hormone and 1,25(OH)2 vit D3 on bone, gastrointestinal tract, and the kidney 4.