Unii-5R78837D4A

In some studies performed in polluted water, it was showed that strontium is able to bind to plasma proteins. In human plasma studies, it has been shown a possible recovery of 45-60% of administered strontium by ultrafiltration, while other studies confirm a protein binding of 30-40%.

Metastatic bone lesions are zones of high bone mineral turnover. Thus, there is a constant need of calcium supply for the development of the malignancy. Strontium chloride 89 is a divalent ion, similar to calcium, therefore it is taken up by sites of active osteogenesis. This relieves bone metastatic-driven pain withouth generating important side effects and it also presents a very little radioprotection concern. Once combined with external beam radiotherapy, strontium chloride 89 can emit β particules with a maximum range in tissue of 6-8mm. This radiation is capable to reduce new bone metastases and produces an analgesic role.

Strontium chloride 89, a similar to calcium divalent ion, concentrates in areas of increased osteogenesis, by being taken up into the inorganic matter of the bone. Strontium chloride 89 presents a 10-fold higher affinity for metastatic bone. Some reports indicate that after Strontium chloride 89 is incorporated into the osteoid matrix adjascently to the metastatic cells, it emits β-rays getting even to 1.3-64Gy. Thus, there is a possible tumoricidal effect driven by the radiation selectively emited by strontium chloride 89 into metastatic bones.

Strontium can interact with components than normally bind to calcium, including hydroxyapatite (main component of mineralized bone), calcium-binding or calcium-transport proteins. It can form complexes with different inorganic anions like carbonate, citrate, phosphate, carboxylic acid or lactate.

Following intravenous injection, strontium chloride 89 behaves like its calcium analog. It clears rapidly from the blood stream and selectively gets localized on the bone mineral, preferentially in zones of osteogenesis, where it can stay retained for about 14 days.