Abstract
The delivery of nanoparticulate medicines to the lungs via the pulmonary route presents many challenges. Nanoparticles tend to lack sufficient mass and are principally exhaled and not deposited in the lungs. However, they also tend to form aggregates or agglomerates to reduce the free energy of the system due to the large surface. Optimal deposition in the deep lungs tends to occur when inhaled particles have a 1-5 µm Mass Median Aerodynamic Diameter (MMAD). This project prepared agglomerated nanoparticles having modified drug release properties with an aerodynamic particle size suitable for delivery to the lungs.|First, a water-soluble model drug was formulated as microencapsulated dry powders using aqueous spray drying with a fluid nozzle. The spray dried particles had an aerodynamic and geometric particle size distributions was in the 1-5 µm range. Drug release was evaluated using USP- II apparatus and showed all formulations had accelerated drug release with no significant differences between formulations. All the formulations showed almost 80% drug release within 10 min.|Second, nanoparticles were prepared using Tolnaftate as a water-insoluble model drug. Nanoparticles where spray dried using a two-fluid nozzle to prepare agglomerated nanoparticles. Microencapsulated formulations were manufactured with excipients along with the agglomerated nanoparticles with the help of three- fluid nozzled spray drier. Formulations had aerodynamic and geometric particle size distributions in the 1-5 µm range. Drug release from agglomerated nanoparticles was evaluated using a USP- II apparatus and confirmed burst drug release. All the formulations showed approximately 80% drug release within 10 min. However, agglomerated nanoparticles showed significant differences based on formulation properties. The difference in the release profile was achieved because of the increment of disintegrant and reduction of the pore-forming agent's amounts in the formulation.|In conclusion, it can be said that agglomerated nanoparticles can be prepared that are suitable for pulmonary drug delivery as they release nanoparticles rapidly in the deep lung.