D-(+)-Methyl-alpha-(2-thienylethamino)(2-chlorophenyl)acetate hydrochloride
[CAS# 141109-19-5]

Identification

• Classification: Organic raw materials >> Carboxylic compounds and derivatives >> Salt of carboxylic acid ester and its derivatives
• Name: D-(+)-Methyl-alpha-(2-thienylethamino)(2-chlorophenyl)acetate hydrochloride
• Molecular Formula: C₁₅H₁₆ClNO₂S.HCl
• Molecular Weight: 346.27
• CAS Registry Number: 141109-19-5
• EC Number: 604-219-8
• SMILES: COC(=O)[C@H](C1=CC=CC=C1Cl)NCCC2=CC=CS2.Cl

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H315-H319-H335
• Safety Statements: P261-P264-P264+P265-P271-P280-P302+P352-P304+P340-P305+P351+P338-P319-P321-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Eye irritation	Eye Irrit.	2	H319
Specific target organ toxicity - single exposure	STOT SE	3	H335
Skin irritation	Skin Irrit.	2	H315

Discovery and Applications

D-(+)-Methyl-a-(2-thienylethylamino)(2-chlorophenyl)acetate hydrochloride, known more commonly as Dexchlorpheniramine or its racemic form, was discovered in the mid-20th century as part of efforts to develop effective antihistamines. The chemical, a thienylethylamine derivative, was synthesized by modifying chlorpheniramine to enhance its potency and reduce sedation. The incorporation of a thiophene ring aimed to improve the pharmacological profile, offering a more targeted action on histamine H1 receptors. The D-(+) enantiomer, being more active, was isolated to maximize efficacy and minimize side effects. This discovery led to the development of a highly effective antihistamine used for managing allergic reactions.

Dexchlorpheniramine is a potent H1 antihistamine, widely used in the treatment of allergic conditions such as hay fever, urticaria, and allergic rhinitis. By competitively inhibiting histamine at H1 receptors, it reduces symptoms like itching, sneezing, runny nose, and watery eyes. Its efficacy in blocking histamine makes it a first-line treatment in managing acute allergic reactions and chronic allergy symptoms. It is particularly effective for seasonal allergies, providing relief from symptoms triggered by pollen and other environmental allergens. Its ability to mitigate nasal and ocular symptoms contributes to improved quality of life during allergy seasons, making it a preferred choice for individuals with recurrent seasonal allergies. Dexchlorpheniramine is also used in treating skin allergies and conditions like atopic dermatitis and contact dermatitis. Its antihistamine action helps alleviate itching and inflammation, making it a valuable option in dermatological therapy. Topical formulations and systemic administration can be used depending on the severity of the allergic response.

Beyond allergies, dexchlorpheniramine is often included in combination with other drugs in cold and flu medications. It helps manage symptoms such as nasal congestion, sneezing, and runny nose associated with common colds and viral infections. Its role in multi-symptom relief products enhances patient comfort by addressing multiple symptoms simultaneously. It is frequently combined with decongestants, analgesics, and antitussives to provide comprehensive relief from cold and flu symptoms. This combination approach allows for the effective management of various symptoms with a single medication, improving patient adherence and convenience.

Although primarily an antihistamine, dexchlorpheniramine possesses mild sedative properties due to its ability to cross the blood-brain barrier. This sedative effect can be beneficial in conditions where relaxation and sleep induction are needed, such as in cases of severe allergic reactions accompanied by agitation or anxiety. However, care is taken to balance efficacy with potential drowsiness, especially in daytime use. Its anticholinergic properties can also provide additional benefits in reducing nasal and bronchial secretions, making it useful in managing symptoms like rhinorrhea and postnasal drip. These properties are harnessed in formulations targeting respiratory symptoms where excessive mucus production is a concern.

Dexchlorpheniramine is available in various formulations, including tablets, syrups, and injectable forms, allowing flexibility in dosing and administration. Its tolerability profile, with controlled sedation and minimal side effects, makes it suitable for use in both adults and children, provided that dosing is adjusted appropriately. Common side effects include mild drowsiness, dry mouth, and gastrointestinal discomfort. Patients are advised to avoid operating heavy machinery or driving while on the medication, especially when starting treatment or adjusting doses. Monitoring and patient education can effectively manage and mitigate these effects.

References

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