Ca2¹²⁵ receptor ( IC50 = 43 nM )

NPS-2143 (SB-262470A) causes the plasma PTH levels in rats to quickly increase by 4 to 5 times[1]. Mean arterial blood pressure (MAP) in normotensive rats with parathyroid glands is significantly elevated by intravenous NPS-2143 (1 mg/kg) administration[2].

The HEK 293 4.0-7 clonal cell line is utilized in a high-throughput screening format to identify Ca²⁺2+ receptor agonists and allosteric activators. A quantitative and functional evaluation of the Ca²⁺2+ receptor activity in these cells Ca²⁺n be obtained by measuring changes in the concentration of cytoplasmic [Ca²⁺2+]i. The outcomes of this assay are comparable to those obtained using a homologous expression system of bovine parathyroid cells. Using a fluorescence imaging plate reader or a specially designed spectrofluorimeter, HEK 293 4.0-7 cells loaded with either fura-2 or fluo-3 Ca²⁺n have their fluorescence measured continuously and online. The concentration of extracellular Ca²⁺2+ is increased from 1.0 mM to 1.75 mM after NPS-2143 has been incubated with cells for one minute. Individual NPS-2143 tests are conducted at concentrations ranging from 20 μM to 80 μM, with those that inhibit the control response by more than 40% deemed biologiCa²⁺lly active. Concentration-response curves are used to ascertain the potencies (IC50) of NPS-2143 with biologiCa²⁺l activity. Following this, an initial evaluation of selectivity is conducted by examining the effects of NPS-2143 at a concentration several times that of its IC50 on [Ca²⁺2+]i evoked by other G protein-coupled receptors. The activation of intracellular Ca²⁺2+ is correlated with the expression of thrombin, bradykinin, and ATP receptors in wild-type HEK 293 cells as well as HEK 293 4.0-7 cells. To evaluate a compound's nonselective action on G protein-coupled receptors quickly, these responses Ca²⁺n be examined. Other assays for selectivity involve using HEK 293 cells that have been modified to express receptors that are most similar to the Ca²⁺2+ receptor in terms of topology and sequence. These comprise GABABRs (gamma-aminobutyric acid type B) and various metabotropic glutamate receptors, either native or chimeric. In order to couple to the activation of phospholipase C and the release of intracellular Ca²⁺2+ in HEK 293 cells, chimeric receptors are synthesized using partial sequences of metabotropic glutamate receptors and Ca²⁺2+ receptors. In an iterative process, NPS-2143 lacking pan-activity are then exposed to structural modifiCa²⁺tions, and their potencies and selectivities are tracked using these HEK 293 4.0-7 cell assays.

Calcilytics NPS-2143 has been shown to reduce the CaSR's sensitivity to [Ca2+]o, which attenuates signal transduction in vitro and increases PTH secretion in vivo. Furthermore, for the wild-type CaSR and mutant CaSR (T151R, P221L, E767Q, G830S, and A844T), respectively, the EC50 values of NPS-2143 are 4.27, 1.56, 1.61, 2.46, 2.07, and 3.15 mM. In addition to this, it has been shown that NPS-2143 inhibits the [Ca2+]o-induced cytosolic calcium signal in HEK 293T cells expressing CaSR in a concentration-dependent way.

[1]. Calcilytic compounds: potent and selective Ca2+ receptor antagonists that stimulate secretion of parathyroid hormone. J Pharmacol Exp Ther. 2001 Oct;299(1):323-31.

[2]. Hypertensive effect of calcilytic NPS 2143 administration in rats. J Endocrinol. 2006 Oct;191(1):189-95.

[3]. Involvement of the calcium-sensing receptor in human taste perception. J Biol Chem. 2010 Jan 8;285(2):1016-22.

[4]. Calcium-sensing receptor mediates dietary peptide-induced CCK secretion in enteroendocrine STC-1 cells. Mol Nutr Food Res. 2012 May;56(5):753-60.

[5]. Calcium-sensing receptor: a sensor and mediator of ischemic preconditioning in the heart. Am J Physiol Heart Circ Physiol. 2010 Nov;299(5):H1309-17.

Drug Indication
Investigated for use/treatment in osteoporosis.

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Mechanism of Action
NPS-2143 is the prototype calcilytic drug, designed to act on calcium receptors on the surface of parathyroid glands, stimulating the release of the body's own stores of native parathyroid hormone (PTH).

C24H25CLN2O2

408.92

408.16

C, 70.49; H, 6.16; Cl, 8.67; N, 6.85; O, 7.82

284035-33-2

NPS-2143 hydrochloride; 324523-20-8

6918446

White to off-white solid powder

1.23 g/cm3

608.4ºC at 760 mmHg

1.17E-15mmHg at 25°C

1.631

5.106

2

4

8

29

560

1

N#CC1=C(OC[C@@H](CNC(C)(CC2=CC=C3C=CC=CC3=C2)C)O)C=CC=C1Cl

PZUJQWHTIRWCID-HXUWFJFHSA-N

InChI=1S/C24H25ClN2O2/c1-24(2,13-17-10-11-18-6-3-4-7-19(18)12-17)27-15-20(28)16-29-23-9-5-8-22(25)21(23)14-26/h3-12,20,27-28H,13,15-16H2,1-2H3/t20-/m1/s1

2-chloro-6-[(2R)-2-hydroxy-3-[(2-methyl-1-naphthalen-2-ylpropan-2-yl)amino]propoxy]benzonitrile

2934.99.9001

Powder      -20°C    3 years

                     4°C     2 years

In solvent   -80°C    6 months

                  -20°C    1 month

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

Solubility in Formulation 1: ≥ 2.5 mg/mL (6.11 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL.
Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution.

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Solubility in Formulation 2: ≥ 2.5 mg/mL (6.11 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution.
For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 25.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.

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Solubility in Formulation 3: 2% DMSO +Corn oil : 10mg/mL

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