Gadopentetic acid does not have a traditional "target" in the sense of a receptor or enzyme. Its mechanism of action is physical. As a paramagnetic agent, it contains a gadolinium ion with seven unpaired electrons, which creates a strong magnetic moment. When injected intravenously, it distributes in the vascular and extracellular spaces. The paramagnetic gadolinium ion shortens the T1 and T2 relaxation times of nearby water protons, leading to an increase in signal intensity on T1-weighted MRI images. This enhances the contrast between normal and pathological tissues, particularly in areas with increased vascularity or disrupted blood-brain barrier.

In vitro, Gadopentetic acid is used as a reference standard and in quality control for MRI contrast agents. Its relaxivity, a measure of its ability to shorten T1 relaxation time, is measured in aqueous solutions. The compound is not typically used in cell-based pharmacological assays, as its mechanism of action is physical and does not involve receptor or enzyme interactions.

Gadopentetate (Gd-DTPA) (tail intravenously; 2 and 5 mmol/kg; single dose) exhibits a pyramidal cycle, TCA cycle, activation, and disruption as part of a systemic activating response. An animal model of how group dynamics are disrupted: rat [1]
In vivo, Gadopentetic acid is a widely used contrast agent for MRI. It is administered intravenously and distributes in the vascular and extracellular spaces. It is used to enhance the visibility of lesions with abnormal vascularity in the brain, spine, and head and neck. It is commonly employed in neurological, cardiovascular, and oncological imaging. Its use allows for better visualization of tumors, inflammation, and other pathologies.

For in vitro assays, the primary parameter measured for Gadopentetic acid is its relaxivity. This is determined by measuring the T1 relaxation time of water protons in solutions containing varying concentrations of the compound using a relaxometer or an MRI scanner. The relaxivity (r1) is calculated from the slope of the relaxation rate (1/T1) versus concentration plot. This assay is used to characterize the contrast-enhancing properties of the compound.

Gadopentetic acid is not typically used in standard cell-based pharmacological assays. Its effect is physical and does not involve cellular receptors or signaling pathways. However, its cellular uptake and distribution can be studied in vitro using cell culture models, where its concentration in cells can be measured by ICP-MS (inductively coupled plasma mass spectrometry).

Animal/Disease Models: Rats[1]
Doses: 2 and 5mmol/kg
Route of Administration: tail vein injection, single
Experimental Results:Observed urinary and serum metabonomic recovery but the metabolic effects of high-dosed (5mmol/kg) lasted long. Observed hyperlipidemia after Gd-DTPA injection.
In vivo, the efficacy of Gadopentetic acid as a contrast agent is evaluated in animal models or in clinical trials. The compound is administered intravenously, and MRI scans are performed at various time points. The signal enhancement in target tissues is measured, and the pharmacokinetic parameters, such as distribution and clearance, are determined.

Absorption, Distribution and Excretion
Following injection, gadopentetate dimeglumine is primarily excreted in the urine, with 83 ± 14% (mean ± standard deviation) of the dose excreted within 6 hours and 91 ± 13% (mean ± standard deviation) within 24 hours. 266 ± 43 mL/kg 1.94 ± 0.28 mL/min/kg [Normal Subjects] Metabolism/Metabolites No biotransformation or degradation was detected. Biological Half-Life Distribution half-life: 12 minutes; elimination half-life: 100 minutes.
Gadopentetic acid has a molecular formula of C14H20GdN3O10 and a molecular weight of 547.57 g/mol for the free acid. Its CAS number is 80529-93-7. It is typically supplied as a white solid or as a solution. It is soluble in water. For in vitro studies, it is dissolved in water or buffer. For in vivo administration, it is formulated as a sterile solution for intravenous injection. Storage is recommended at -20°C, protected from light.

Effects During Pregnancy and Lactation
◉ Overview of Use During Lactation
After a mother uses gadopentetate calcium, the gadolinium content in her breast milk is less than 1% of the infant's allowable intake. Furthermore, because gadopentetate calcium is poorly absorbed orally, it is unlikely to enter the infant's bloodstream and will not have any adverse effects on breastfed infants. Gadopentetate calcium releases more free gadolinium than some other gadolinium-containing contrast agents. Some European guidelines recommend suspending breastfeeding for 24 hours after contrast agent injection, but guidelines developed by North American professional organizations state that breastfeeding mothers do not need to interrupt breastfeeding after receiving gadolinium-containing contrast agents. ◉ Effects on Breastfed Infants
No published information found as of the revision date. ◉ Effects on Lactation and Breast Milk
No published information found as of the revision date.
Gadopentetic acid has a well-established clinical safety profile. It is generally safe, but serious adverse reactions, including nephrogenic systemic fibrosis (NSF), have been associated with the use of gadolinium-based contrast agents in patients with severe renal impairment. Its toxicity is primarily related to the potential release of free gadolinium ions, which are toxic. The chelation with DTPA reduces this risk. The LD50 in rats after intravenous administration is 10 mmol/kg.

[1]. Gd-DTPA-induced dynamic metabonomic changes in rat biofluids. Magn Reson Imaging. 2017 Dec;44:15-25.

[2]. Analysis of pharmacokinetics of Gd-DTPA for dynamic contrast-enhanced magnetic resonance imaging. Magn Reson Imaging. 2016 Sep;34(7):1034-40.

complex of gadolinium and the chelating agent diethylenetriaminepentaacetic acid (DTPA, see pentaacetic acid) is used to enhance images on magnetic resonance imaging (MRI) of the brain and spine. (From Martindale Pharmacopoeia, 30th edition, p. 706)
A complex of gadolinium and the chelating agent diethylenetriaminepentaacetic acid (DTPA, see pentaacetic acid) is used to enhance images on magnetic resonance imaging (MRI) of the brain and spine. (From Martindale Pharmacopoeia, 30th edition, p. 706)
Indications

For use in adults and children (2 years and older) on magnetic resonance imaging (MRI) to visualize vascular abnormalities in the brain (intracranial lesions), spine and related tissues, and head and neck vascular abnormalities. It may also be used to assist in visualizing vascular abnormalities in vivo (excluding the heart).
FDA Label
Mechanism of Action

Based on the behavior of protons in a strong magnetic field, which is interpreted and converted into images by a magnetic resonance (MR) instrument. MR imaging is primarily based on proton density and proton relaxation dynamics. MR instruments are sensitive to two distinct relaxation processes: T1 (spin-lattice or longitudinal relaxation time) and T2 (spin-spin or transverse relaxation time). Paramagnetic contrast agents contain one or more unpaired electrons, which enhance the T1 and T2 relaxation rates of protons in their molecular environment. The proton relaxation effect (PRE) of unpaired electrons is 700 times stronger than that of the proton itself. In MRI, the imaging of normal and diseased brain tissue depends on variations in radiofrequency signal intensity, which are caused by changes in proton density, alterations in T1, and changes in T2. When placed in a magnetic field, gadopentetate dimeglumine can shorten the T1 and T2 relaxation times in tissues where it accumulates. In the central nervous system (CNS), gadopentetate dimeglumine enhances the visualization of normal tissues lacking the blood-brain barrier, such as the pituitary gland and meninges. Gadopentetate dimeglumine cannot cross the intact blood-brain barrier; therefore, it does not accumulate in normal brain tissue or in central nervous system lesions that do not cause blood-brain barrier abnormalities (e.g., cysts, mature postoperative scars). Abnormal vascular distribution or disruption of the blood-brain barrier can cause gadopentetate dimeglumine to accumulate in lesions such as tumors, abscesses, and subacute infarctions. Outside the central nervous system, gadopentetate dimeglumine rapidly reaches equilibrium in the interstitial spaces and enhances signaling in all tissues depending on the dose and size of the interstitial spaces. Studies have also found that this compound can inhibit human erythrocyte 6-phosphate gluconate dehydrogenase.
Gadopentetic acid is an FDA-approved prescription drug for use as a contrast agent in MRI. It is marketed under the brand name Magnevist. It is one of the first gadolinium-based contrast agents to be introduced. Its mechanism of action involves the shortening of T1 relaxation times, enhancing contrast in MRI images. It is used in a wide range of diagnostic imaging applications.

C14H18GDN3O10.2H

547.57

548.039

80529-93-7

16212436

White to off-white solid powder

721.1ºC at 760 mmHg

129ºC (dec.)(lit.)

389.9ºC

3

14

13

29

497

0

JBUMALASVLVYKI-UHFFFAOYSA-K

InChI=1S/C14H23N3O10.Gd.H2O/c18-10(19)5-15(1-3-16(6-11(20)21)7-12(22)23)2-4-17(8-13(24)25)9-14(26)27;;/h1-9H2,(H,18,19)(H,20,21)(H,22,23)(H,24,25)(H,26,27);;1H2/q;+3;/p-3

2-[bis[2-[carboxylatomethyl(carboxymethyl)amino]ethyl]amino]acetate;gadolinium(3+);hydrate

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

Note: Please store this product in a sealed and protected environment (e.g. under nitrogen), avoid exposure to moisture and light.

Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

H2O : ~100 mg/mL (~182.63 mM)
DMSO : ~1 mg/mL (~1.83 mM)

Solubility in Formulation 1: 100 mg/mL (182.63 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with sonication.

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 (Please use freshly prepared in vivo formulations for optimal results.)