Pemirolast potassium (formerly TWT 8152; BMY 26517; TWT-8152; BMY-26517; Alegysal and Alamast), the potassium salt of Pemirolast, is a poten and orally bioactive histamine H1 antagonist and mast cell stabilizer with potential antiallergic effects. For the treatment of asthma, a nonbronchodilator antiallergy medication candidate is being researched.

Physicochemical Properties

Molecular Formula	C10H7KN6O
Molecular Weight	266.3
Exact Mass	266.031
Elemental Analysis	C, 45.10; H, 2.65; K, 14.68; N, 31.56; O, 6.01
CAS #	100299-08-9
Related CAS #	Pemirolast; 69372-19-6
PubChem CID	443866
Appearance	Light yellow to green yellow solid powder
Boiling Point	454.8ºC at 760mmHg
Melting Point	310-311ºC (dec.)
Flash Point	228.9ºC
Vapour Pressure	1.85E-08mmHg at 25°C
Hydrogen Bond Donor Count	0
Hydrogen Bond Acceptor Count	6
Rotatable Bond Count	1
Heavy Atom Count	18
Complexity	495
Defined Atom Stereocenter Count	0
SMILES	O=C1C(C2=N[N-]N=N2)=CN=C3N1C=CC=C3C.[K+]
InChi Key	NMMVKSMGBDRONO-UHFFFAOYSA-N
InChi Code	InChI=1S/C10H7N6O.K/c1-6-3-2-4-16-9(6)11-5-7(10(16)17)8-12-14-15-13-8;/h2-5H,1H3;/q-1;+1
Chemical Name	potassium;9-methyl-3-(1,2,3-triaza-4-azanidacyclopenta-2,5-dien-5-yl)pyrido[1,2-a]pyrimidin-4-one
Synonyms	TWT-8152; BMY 26517; TWT 8152; BMY 26517; TWT8152; BMY 26517; Pemirolast; Pemirolast potassium. trade name: Alegysal and Alamast.
HS Tariff Code	2934.99.9001
Storage	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, avoid exposure to moisture.
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

Targets	Histamine H1 receptor
ln Vitro	In vitro activity: Pemirolast potassium (BMY 26517) is a brand-new oral nonbronchodilator antiallergy drug that's currently being tested for use in treating asthma. In addition to being shown to inhibit the release of peptides such as substance P, [2] neurokinin (NK) A, and calcitonin gene-related peptide (CGRP) from sensory nerves, pemirolast potassium (BMY 26517) also inhibits the release of chemical mediators from tissue mast cells.[3] In order to prevent pulmonary hypersensitivity reactions to medications like paclitaxel, pemirolast potassium is used as a treatment for allergic conjunctivitis.[4]
ln Vivo	Pemirolast potassium (BMY 26517) inhibits the release of substance P in rats, thereby reducing their intake of kaolin. [2] Pemirolast inhibits the release of sensory neuropeptides in rats, thereby potently attenuating hypersensitivity reactions to paclitaxel. [3]
Animal Protocol	Rats
References	[1]. Ann Allergy . 1992 Jun;68(6):488-91. [2]. Eur J Pharmacol . 2011 Jul 1;661(1-3):57-62. [3]. Neuropharmacology . 2004 May;46(6):888-94. [4]. J Ocul Pharmacol Ther . 2002 Oct;18(5):475-88.
Additional Infomation	Pemirolast Potassium is the potassium salt form of pemirolast, a pyrimidinone derivative with antiallergic property. Pemirolast potassium exerts its action by blocking the antigen-mediated calcium ion influx into mast cells. This prevents mast cell degranulation, resulting in mast cell stabilization and inhibition of the release of inflammatory mediators, histamine and leukotrienes, which are involved in the allergic process. Pemirolast potassium also prevents inflammatory mediator release from eosinophils.

Solubility Data

Solubility (In Vitro)	DMSO: <1 mg/mL Water: ~53 mg/mL (~199.0 mM) Ethanol: <1 mg/mL
Solubility (In Vivo)	Solubility in Formulation 1: 100 mg/mL (375.52 mM) in PBS (add these co-solvents sequentially from left to right, and one by one), clear solution; with sonication.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	3.7552 mL	18.7758 mL	37.5516 mL
	5 mM	0.7510 mL	3.7552 mL	7.5103 mL
	10 mM	0.3755 mL	1.8776 mL	3.7552 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.