Lozenges as delivery system for upper respiratory catarrh medication

Lozenges, the small medicated candies that dissolve slowly in the mouth have always been a favoured delivery system, particularly for drugs meant for relieving sore throats and cold symptoms. This predilection can be attributed mainly to their ability to keep the naso-pharyngeal mucosa moist, enhance the swallowing reflex and provide longer contact time of the drug with the naso-pharyngeal mucosa. A number of innovative technologies have been developed to improve the conventional forms of lozenges i.e. hard candies and compressed tablets. These include the use of novel ingredients/ techniques to enhance taste, reduce calorie content, facilitate quick manufacture and modify the drug release characteristics. Though used extensively for delivery of all kinds of medications for upper respiratory tract disorders, lozenges remain one of the least researched delivery systems. This article reviews various aspects of lozenges as a delivery system. The rationale behind the use of lozenges as the most favoured dosage form for delivery of anti-tussive substances is presented. Delving deeper, various anti-tussive substances that have been delivered as the lozenges including the patents thereof, are also discussed briefly along with the innovative approaches that have been utilised for their formulation improvements.