15826-37-6

White Crystalline Powder

Intal,Fisons,UK,1969

Anti Asthamatic

antiasthmatic, antiallergy

Chromone complex which blocks mast cell degranulation

ChEBI: An organic sodium salt that is the disodium salt of cromoglycic acid.

Cromolyn sodium (Intal) is chemically related drugs called chromones that is used for the prophylaxis of mild or moderate asthma. It is administered by inhalation and has very good safety profiles, making them particularly useful in treating children.

To a solution of 970 parts of 2,6-dihydroxyacetophenone and 325 parts of epichlorohydrin in 1,500 parts of hot isopropanol was added, with stirring under reflux, a solution of 233 parts of 85% KOH in 2,500 parts of isopropanol and sufficient water (ca 100 parts) to dissolve the solid. The mixture was heated, with stirring, under reflux for 48 hours. Half the solvent was then distilled off and 5,000 parts of water were added. The mixture was cooled and the solid filtered off and washed with isopropanol and ether. It was then recrystallized from 12,500 parts of isopropanol to obtain a first crop of 380 parts and a second crop, after concentration, of 300 parts of 1,3-bis(2- acetyl-3-hydroxyphenoxy)-2hydroxypropane.
4.6 parts of 1,3-bis(2-acetyl-3-hydroxyphenoxy)-2-hydroxypropane were reacted with diethyl oxalate and the product cyclized to obtain 4.4 parts of pure diethyl ester of 1,3-bis(2-carboxychromon-5-yloxy)-2-hydroxypropane as pale yellow crystals melting between 180° and 182°C from a mixture of benzene and petrol, 4 parts of the diethyl ester of 1,3-bis(2-carboxychromon5-yloxy)-2-hydroxypropane were saponified with sodium hydroxide to obtain 3.2 parts of the disodium salt tetrahydrate as colorless crystals from aqueous alcohol.

Bronchodilator

Cromolyn sodium, disodium 1,3-bis(2-carboxychromon-5-yloxy)-2-hydroxypropane (Intal), isa hygroscopic, white, hydrated crystalline powder that is solublein water (1:10). It is tasteless at first but leaves a veryslightly bitter aftertaste. The pK of cromolyn is 2. It is availableas a solution for a nebulizer, an aerosol spray, a nasal solution,an ophthalmic solution, and an oral concentrate.
Nebulized and aerosol cromolyn has been used for prophylacticmanagement of bronchial asthma and prevention ofexercise-induced bronchospasm. Cromolyn nasal solution isused for the prevention and treatment of allergic rhinitis, andoral concentrate is used to treat the histaminic symptomsof mastocytosis (diarrhea, flushing, headaches, vomiting, urticaria,abdominal pain, nausea, and itching). Topical cromolyn(eye drops) is used to treat allergic conjunctivitis andkeratitis. In the treatment of asthma, cromolyn efficacy is manifestedby decreased severity of clinical symptoms, or need for concomitant therapy, or both. Long-term use is justified if thedrug significantly reduces the severity of asthma symptoms;permits a significant reduction in, or elimination of, steroiddosage; or improves management of those who have intolerableside effects to sympathomimetic agents or methylxanthines.For cromolyn to be effective, it must be administered atleast 30 minutes prior to antigen challenge and administered atregular intervals (see dosing information that follows). Wheninhaled, the powder does produce irritation in some patients.Also, overuse of cromolyn can result in tolerance.

Cromolyn blocks the release of histamine and other pro-inflammatory mediators from mast cells.

The precise mechanism or mechanisms whereby cromolyn sodium and nedocromil sodium exert their antiasthmatic activities is unknown. Early work suggested that these agents act by “stabilizing” mast cells, preventing mediator release. However, several other compounds exhibit greater potency for stabilization of mast cells yet possess no clinical efficacy in asthma.This suggests that the therapeutic activity of cromolyn sodium and nedocromil sodium in asthma is related to one or more other pharmacological mechanisms. Postulates include inhibitory effects on irritant receptors, nerves, plasma exudation, and inflammatory cells in general.

Cromolyn sodium is a bischromone that contains the fundamental benzopyrone moiety of khellin. The two chromone rings are necessary for activity and must be coplanar, with a linking chain of no longer than six carbons. If one changes the linking chain to positions 8 and 8′, coplanarity cannot be maintained, and the compound loses all activity. Cromolyn sodium is poorly absorbed from the lungs (~8%), insignificantly from the eye (~0.07%), and by approximately 1% from the GI tract. What little that finds its way into systemic circulation is eliminated intact in the urine and the bile. For the treatment of asthma, cromolyn sodium is available as a solution for both intranasal and inhalation administration. There also is an oral concentrate (100 mg/5 mL), which is administered as a 200-mg dose given four times a day.

Cromolyn sodium is used almost exclusively for the prophylactic treatment of mild to moderate asthma and should not be used for the control of acute bronchospasm. This agent is effective in about 60 to 70% of children and adolescents with asthma. Unfortunately, there is no reliable means to predict which patients will respond.It is less effective in older patients and in patients with severe asthma. It may take up to 4 to 6 weeks of treatment for cromolyn sodium to be effective in chronic asthma, but it is effective after a single dose in exercise-induced asthma. With respect to clinical efficacy, cromolyn sodium and nedocromil sodium do not differ in a substantial way.

Cromolyn sodium is the least toxic of available therapies for asthma. Adverse reactions are rare and generally minor. Those occurring in fewer than 1 in 10,000 patients include transient bronchospasm, cough or wheezing, dryness of throat, laryngeal edema, swollen parotid gland, angioedema, joint swelling and pain, dizziness, dysuria, nausea, headache, nasal congestion, rash, and urticaria.

4°C, protect from light, stored under nitrogen