Development and characterization of spray dried microparticles for pulmonary delivery of antifungal drug.

Invasive pulmonary aspergillosis is a life threatening fungal infection mainly caused by Aspergillus species. Available treatment strategy against pulmonary aspergillosis is having very limited applicability, due to its toxicity and low circulation half-life. Pulmonary drug delivery is one of the strategies that can minimize these pitfalls. In the present study, polymeric and lipidic nanoparticles of amphotericin B were prepared by spray drying technique using hydroxypropylmethylcellulose (HPMC) and stearylamine with oleic acid respectively. Formulations were characterized for particle size, zeta potential, entrapment efficiency, in-vitro release studies, uptake analysis and in-vivo bio distribution studies. Developed polymeric and nanostructured lipid carriers (NLCs) were found in submicron size (600-700nm) and spherical in shape. Studies suggested that NLCs have better entrapment efficiency (77.1±5.5 %) as compared to HPMC carrier (71.28±5.22 %). Both formulations provided sustained drug release (HPMC, 82.05% releases up to 32 hrs and NLC, 88.2 % up to 40 hrs) and reduced dose dumping that may be helpful to reduce the toxicity and improve patient compliance. In-vitro antifungal studies suggested that stearylamine formulations exhibited better antifungal activity over control and HPMC formulations. Pharmacokinetic and organ distribution studies also support our hypothesis i.e. localized drug delivery for prolong period, improving the therapeutic effectiveness of the encapsulated drug against pulmonary aspergillosis. Studies suggested that drug delivery by pulmonary route is beneficial for local action in lungs.