چکیده (انگلیسی):

This investigation was undertaken to evaluate practical feasibility of site specific pulmonary
delivery of liposomal encapsulated Dapsone (DS) dry powder inhaler for prolonged drug retention in
lungs as an effective alternative in prevention of Pneumocystis carinii pneumonia (PCP) associated with
immunocompromised patients. DS encapsulated liposomes were prepared by thin film evaporation
technique and resultant liposomal dispersion was passed through high pressure homogenizer. DS nanoliposomes
(NLs) were separated by ultra centrifugation and characterized. NLs were dispersed in
phosphate buffer saline (PBS) pH 7.4 containing different carriers like lactose, sucrose, and hydrolyzed
gelatin, and 15% L-leucine as antiadherent. The resultant dispersion was spray dried and spray dried
formulation were characterized to ascertain its performance. In vitro pulmonary deposition was assessed
using Andersen Cascade Impactor as per USP. NLs were found to have average size of 137±15 nm, 95.17±
3.43% drug entrapment, and zeta potential of 0.8314±0.0827 mV. Hydrolyzed gelatin based formulation
was found to have low density, good flowability, particle size of 7.9±1.1 μm, maximum fine particle fraction
(FPF) of 75.6±1.6%, mean mass aerodynamic diameter (MMAD) 2.2±0.1 μm, and geometric standard
deviation (GSD) 2.3±0.1. Developed formulations were found to have in vitro prolonged drug release up
to 16 h, and obeys Higuchi's Controlled Release model. The investigation provides a practical approach
for direct delivery of DS encapsulated in NLs for site specific controlled and prolonged release behavior
at the site of action and hence, may play a promising role in prevention of PCP.