Dr. Hetal Thakkar and her students, Sunil Thakor and Dr. Praveen Srivastava have been granted Indian Patent for their invention on Liposomal Dry Powder Inhaler (LDPI) of Azithromycin for the treatment of respiratory infection. The title of the patent is “Liposomal Dry Powder Inhaler (LDPI) of Azithromycin” bearing the patent number 358732.
The research work was carried out at the Faculty of Pharmacy, The Maharaja Sayajirao University of Baroda by Sunil Thakor, supported by Dr. Praveen Srivastava under guidance of Dr. Hetal Thakkar. The project work was planned taking into consideration the need of a better formulation for treatment of lung infections, which are most prevalent and leading cause of death from infectious diseases in the world.
Azithromycin is the drug of choice for treatment of lung infections but this drug shows a number of side effects like stomach upset, diarrhea/loose stools, nausea, vomiting, abdominal pain when given as tablet.
Azithromycin also shows side effects like fast or pounding heartbeats, fluttering in chest, shortness of breath, and sudden dizziness. These side effects are majorly related to the presence of drug in stomach and blood. So, there always existed a demand of formulation capable of confining drug to its target organ where bacteria causing respiratory infection resides.
Liposomes are vesicles made up of non-toxic lipids and widely used as carrier to target drugs to specific organs. Despite of these advantages, liposomes suffer stability problems that severely hamper their commercialization.
With an aim to focus on utilizing the advantages of liposomes while countering its disadvantages, researchers designed new formulation to be inhaled to lungs via mouth. In this new formulation Azithromycin was encapsulated within liposomes, converted in to dry powder by freeze-drying and filled in capsules for administration to lungs using patient-friendly inhalation devices.
Short term stability studies revealed no change in inhalation properties of these liposomal dry powders when stored under refrigerated conditions. These liposomal dry powder was exhaustively evaluated using various in-vitro and animal studies to establish their potential for the purpose they intended to serve.
The in vivo studies conducted in rats showed prolonged retention of these liposomes (up to 12 hrs) in lungs with lesser appearance in blood. These liposomes slowly released the loaded Azithromycin in lungs and thus avoided the exposure of drug to stomach or blood. This helps in building local drug concentrations required for maximizing effectiveness and minimizing side effects.
Animal studies in rats showed promising results and the formulation is ready for clinical investigation in Human volunteers.