Fail-safe nano-formulation of prodrug of sulfapyridine: Preparation and evaluation for treatment of rheumatoid arthritis.

Aim of the present study was to give a second life to the long-abandoned drug, sulfapyridine (SP) for its anti-arthritic potential by design of nano-vesicular delivery system. For this, intra-articular delivery of its liposomal formulation was tried. As the prepared formulation exhibited rapid drug leakage, an arthritis responsive prodrug of SP showing lability towards synovial enzymes was synthesized to exploit the over-expression of arthritis specific enzymes. Prodrug (SP-PD) exhibited better retention in liposomes as compared to the drug, preventing its escape from synovium. Hydrolysis of SP-PD in human plasma and synovial fluid indicated its high susceptibility to enzymes. The liposomes of SP-PD exhibited larger mean size, less PDI and higher zeta potential as compared to those for SP liposomes. In arthritic rats, prodrug liposomes were found to reverse the symptoms of inflammation, including the levels of biochemical markers. Liposomes of bio-responsive prodrug, therefore, offer a revolutionary approach in the treatment of rheumatoid arthritis.

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.