Ambroxol Lozenges: Introduction and Recent Advances

Dr. Shoaib Ahmad

University School of Pharmaceutical Sciences, Rayat-Bahra University, Mohali 140104 India

*Corresponding Author E-mail: shoaibahmad1999@gmail.com

ABSTRACT:

Ambroxol hydrochloride (trans-4-[(2-amino-3,5-dibrom-benzyl)amino]cyclohexano hydrochloride; CAS 18683-91-5) is a mucolytic agent. It is an ingredient of several cough and cold formulations – particularly syrups and tablets. The pharmacological properties (i.e. anesthetic, analgesic and anti-inflammatory) have aroused the interest of the scientific community in this molecule. As a result, many studies have focused on the formulation of the lozenges of ambroxol hydrochloride. The commercial marketing of these lozenges started in the year 2002. The reported strengths of these lozenges are 15, 20, and 30 mg. The studies have indicated that bioavailability of the drug from lozenges is better than the tablets. It is so apparently because dissolution of the lozenges in the mouth itself adds to the systemic circulation. Hence, the lozenges can be better candidate for treating respiratory tract problems and associated symptoms. The lozenges are usually well tolerated. The present communication is an attempt to present an overview of the recent developments concerning ambroxol hydrochloride lozenges.

KEYWORDS: Ambroxol hydrochloride, Lozenges, Pharmacokinetics, Mucolytic, Anti-Inflammatory, Safety.

INTRODUCTION:

Ambroxol hydrochloride is a well known mucolytic agent. Its chemical name is trans-4-[(2-amino-3,5-dibrom-benzyl)amino]cyclohexano hydrochloride. CAS identification number of this substance is 18683-91-5.

Ambroxol hydrochloride is commonly used an ingredient of several cough and cold formulations – particularly syrups and tablets. The anesthetic, analgesic and anti-inflammatory properties have aroused the interest of the scientific community in this molecule. As a result, many studies have focused on the development of ambroxol hydrochloride lozenges. The lozenges are into commercial market since the year 2002. The reported strengths of these lozenges are 15, 20, and 30 mg. Several scientific studies have indicated that bioavailability of the drug from lozenges is better than the tablets because dissolution of the lozenges in the mouth itself adds to the systemic bioavailability.

Properties of Ambroxol Hydrochloride

Ambroxol hydrochloride has several medicinal properties some of which are as follows:

a. Ambroxol is acts as mucolytic agent in respiratory diseases e.g. bronchitis.

b. It also has local anesthetic effects.

c. It also has anti-inflammatory effects.

Mechanism of Action of Ambroxol Hydrochloride

1. Ambroxol is acts as mucolytic agent.

2. Ambroxol produces analgesia by blockade of ion channels in peripheral neurons¹.

3. Ambroxol exerts anti-inflammatory action by a number of mechanisms²:

a. Inhibition of oxidative stress.

b. Increase in local defense molecules during virus replication.

c. Reduction of pro-inflammatory cytokines and arachidonic acid metabolites.

d. Decrease in inflammatory cell chemotaxis.

e. Reduced lipid peroxidation of tissues.

Recent Developments in Pharmaceutical Aspects of Ambroxol Lozenges :

A randomised, double-blind, placebo-controlled trial was conducted to evaluate use of ambroxol hydrochloride lozenges in sore throat. The lozenges contained 20 mg or 30 mg ambroxol hydrochloride. They were found to have pain-relieving effect in patients suffering from acute sore throat. Though well tolerated, the 30 mg lozenges were as effective as 20 mg ones. This study proved the beneficial effect of local anesthetic properties of ambroxol hydrochloride³.

Utility of ambroxol hydrochloride lozenges in acute oro-pharyngeal catarrh was also proved⁴. An open-label, two-way crossover trial was conducted in Thai volunteers to compare the bioavailability ambroxol lozenges with ambroxol tablet. Pharmacokinetics data was evaluated using a non-compartmental model. The trial postulated that bioavailability of ambroxol from the lozenge might be better⁵. Comparative bioavailability of ambroxol lozenges and tablets has also been studied⁶.

A questionnaire-based survey was conducted to find use of ambroxol-containing lozenges in sore throat⁷. Efficacy and safety of ambroxol lozenges was again evaluated in adult patients of acute uncomplicated sore throat and 20 mg ambroxol lozenges were considered a safe and efficacious treatment⁸.

20 mg ambroxol lozenges were determined to be a safe for patients having mainly local symptoms of pharyngitis⁹. 20 mg ambroxol lozenges were well tolerated by adolescent and adult patients and determined safe and effective for treating acute uncomplicated sore throat¹⁰. A report in 2009 said ambroxol lozenges have the potential to provoke some adverse effects¹¹.

Current and Potential uses of Ambroxol lozenges

Ambroxol lozenges have a number of possibilities for use in treatment of the following conditions:

1. Acute oro-pharyngeal catarrh⁴.

2. Sore throat³

3. Sore throat and pharyngitis associated with common cold².

4. Chronic bronchitis, chronic obstructive pulmonary disease².

5. Pharyngitis⁹.

CONCLUSIONS:

Ambroxol hydrochloride possesses several pharmaco-logical properties i.e. anesthetic, analgesic and anti-inflammatory etc. Lozenges of ambroxol hydrochloride are available as 15, 20, and 30 mg strength lozenges. Bioavailability of the drug from lozenges is better than the tablets because of dissolution of the lozenges in the mouth itself. Hence, the lozenges can be better candidate for treating respiratory tract problems and associated symptoms. The lozenges are usually well tolerated. Elaborate studies are required for the proper assessment of safety profile of the lozenges and to address the issue of adverse effects. Also, there is a need for understanding the exact reason behind the pain relief in sore throat by ambroxol hydrochloride.

ACKNOWLEDGEMENTS:

Author acknowledges the support from Rayat-Bahra University, Mohali.

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Received on 13.07.2016 Modified on 17.07.2016

Res. J. Pharm. Dosage Form. & Tech. 2016; 8(4): 296-297.

DOI: 10.5958/0975-4377.2016.00041.0