Description
Sodium cromoglycate is the sodium salt and common market from of cromoglicic acid, which is a synthetic compound, and as a mast cell stabilizer. It is capable of inhibiting the antigen-induced bronchospasms, and thus being used to treat the asthma and allergic rhinitis. It can also be applied as an ophthalmic solution for the treatment of conjunctivitis and systemic mastocytosis and ulcerative colitis. It is capable of inhibiting the degranulation of mast cells, further preventing the release of histamine and slow-reacting substance of anaphylaxis (SRS-A), the mediators of type I allergic reaction. It is also capable of inhibiting the release of inflammatory leukotrienes and inhibiting calcium influx.
References
https://www.drugbank.ca/drugs/DB01003
https://en.wikipedia.org/wiki/Cromoglicic_acid
Description
Disodium cromoglycateis a relatively nontoxic agent used
for the long-term prevention of many types of
asthma. It has no bronchodilator properties
and is used in the prophylaxis of asthma.
It does not play a role in the treatment of acute
asthmatic attacks including severe asthma.
Chemical Properties
White Crystalline Powder
Originator
Intal,Fisons,UK,1969
Uses
antiasthmatic, antiallergy
Uses
Chromone complex which blocks mast cell degranulation
Definition
ChEBI: An organic sodium salt that is the disodium salt of cromoglycic acid.
Indications
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.
Manufacturing Process
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.
Therapeutic Function
Bronchodilator
General Description
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.
Biochem/physiol Actions
Cromolyn blocks the release of histamine and other pro-inflammatory mediators from mast cells.
Mechanism of action
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.
Pharmacokinetics
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.
Clinical Use
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.
Side effects
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.
