Biokinetic Models
Shaheen A. Dewji, Nolan E. Hertel in Advanced Radiation Protection Dosimetry, 2019
Strontium is a member of the alkaline earth family (Group IIA of the periodic table) and has been shown in human and animal studies to be a physiological analogue of the alkaline earths calcium, barium, and radium. The systemic biokinetics of strontium differs to some extent from that of these other three alkaline earths, due to discrimination between these elements by biological membranes and hydroxyapatite crystals of bone. For example, strontium is less effectively absorbed from the intestines and more effectively excreted by the kidney than calcium, and is lost from bone at a higher rate than calcium over the first few months after uptake to blood. On the other hand, strontium appears to be more effectively absorbed from the intestines and lost from bone at a lower rate than barium or radium. Overall, the systemic behavior of strontium is closer to that of calcium than to that of the heavier alkaline earths, barium, and radium. Nevertheless, collective biokinetic data for all four of these elements help to fill gaps in information for the individual elements, including strontium.
Osteoarthritis
Kohlstadt Ingrid, Cintron Kenneth in Metabolic Therapies in Orthopedics, Second Edition, 2018
Strontium ranelate is a nutrient that is being used in some European countries for the treatment of postmenopausal osteoporosis. A number of formulations of strontium have been used in the United States for the same purpose (including strontium citrate). Studies have provided a preclinical basis for the use of strontium ranelate in osteoarthritis. In OA and normal chondrocytes that are treated with or without interleukin 1β (IL-1β), strontium ranelate has been shown to stimulate the synthesis of type II collagen and proteoglycan (Henrotin et al., 2001). In a three-year post-hoc analysis of the pool of Spinal Osteoporosis Therapeutic Intervention (SOTI) and Treatment of Peripheral Osteoporosis studies, strontium ranelate was shown to significantly decrease the levels of urinary C-terminal telopeptides of type II collagen (u-CTX-II), a cartilage degradation biomarker, compared with placebo (Alexanderson et al., 2007).
Management of bone pain
Nigel Sykes, Michael I Bennett, Chun-Su Yuan in Clinical Pain Management, 2008
One of the major advantages of strontium is its ease of administration, requiring a simple intravenous injection which can be given as an outpatient. Because it produces short-range beta irradiation, there are few if any major radiation hazards associated with its use and no acute toxicity. The only significant contraindications to strontium use are where there is extensive bone marrow depression, since its widespread uptake into bone will result in a radiation dose being delivered to the bone marrow with suppression of hemopoeisis. Urinary incontinence is also a relative contraindication since strontium is excreted in the urine and if there is spillage on to the patient’s skin, clothing, or bed, then contamination will occur. This may be overcome by urethral catheterization for incontinent patients. Renal failure will impair excretion of strontium, prolonging its half-life, and is also a relative contraindication.
Comparative studies on the potential use of 177Lu-based radiopharmaceuticals for the palliative therapy of bone metastases
Published in International Journal of Radiation Biology, 2020
Hesham M. H. Zakaly, Mostafa Y. A. Mostafa, Darya Deryabina, Michael Zhukovsky
The structure of the strontium model is presented in (ICRP 137. 2017). All soft tissues, the liver and the kidneys are included in the three groups labeled “other tissue” (ST0, ST1, ST2): these correspond to the rapid, intermediate and slow transition of activity from the blood, respectively. Blood here is considered to be a uniformly distributed fluid that exchanges activity between soft tissues and the bone surface. Bone tissue, as in the lanthanoid model, is divided into two types: cortical and trabecular. Each of these types of bone tissue is then divided into surface and volume. After a certain time, some of the activity on the surface of the bone tissue moves to the exchange volume of the bone, while the rest returns to the blood (ICRP 137. 2017). Activity from the exchange volume of bone tissue is distributed for up to a month between the surface of the bone and the unchanged volume of bone tissue.
Pharmacokinetics and bioequivalence of two strontium ranelate formulations after single oral administration in healthy Chinese subjects
Published in Xenobiotica, 2019
Dan Zhang, Aihua Du, Xiaolin Wang, Lina Zhang, Man Yang, Jingyi Ma, Ming Deng, Huichen Liu
The brand-name drug Osseor® (strontium ranelate for suspension) has been imported and used in China for a decade. Strontium ranelate is mainly used for preventing fractures in post-menopausal women and men with severe osteoporosis, and patients cannot be treated with other medicines approved for osteoporosis (EMA, 2016). It is composed of two atoms of stable nonradioactive strontium (Sr) and an organic moiety ranelic acid (Reginster et al., 2003). Its chemical structure is shown in Figure 1. In human, the absorption, distribution and binding to plasma proteins of ranelic acid are very low, the accumulation and metabolism of ranelic acid are not found, and the excretion mainly in the form of unchanged drug of absorbed ranelic acid occurs rapidly via the kidney (EMA, 2016; Reginster et al., 2003). The absolute bioavailability of Sr is about 25% after an oral dose of 2 g strontium ranelate, which is reduced by about 60–70% when strontium ranelate is taken with calcium (Ca) or food. Bone tissue has a high affinity for Sr, while the binding of Sr to human plasma proteins is low, so most of the absorbed Sr is deposited in the bones. Sr is not metabolized, its excretion occurs via the kidneys and the gastrointestinal tract, and its half-life is approximately 60 h (EMA, 2016).
Radiobiological and social considerations following a radiological terrorist attack; mechanisms, detection and mitigation: review of new research developments
Published in International Journal of Radiation Biology, 2022
Tanya Kugathasan, Carmel Mothersill
Out of the 8000 radioactive isotopes, there are approximately 13 isotopes that are considered the highest risk of terrorism (Anderson and Bokor 2013). These isotopes include tritium, cobalt 60, strontium 90, iodine 131, cesium 137, cesium 134, iridium 192, uranium 235, plutonium 238, americium 241 and californium 252. The fission of U-235 and Pu-239 are what create nuclear explosions. These isotopes are also used in nuclear reactors and can be very dangerous if inhaled (Radiation Emergency Medical Management 2021). Sr-90 is a fission product of uranium and is commonly used as radioactive tracers, heat source for navigational beacons and used in weather stations and space (Anderson and Bokor 2013). Tritium, Cs-134 and Cs-137 can also be produced through fusion in thermonuclear weapons (Anderson and Bokor 2013). Isotopes like Am-241, Cf-252 and Co-60 are used for various different applications and pose a threat because they are often stolen for terrorism-related activities. Am-241 is most commonly found in smoke detectors and is utilized in medical diagnostic devices, aircraft fuel gauges, thickness gauges and research (Anderson and Bokor 2013).
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