Novel biocompatible polymer-modified liposome nanoparticles for biomedical applications

The incidence of pulmonary arterial hypertension (PAH) has significantly increased in the past few decades and therefore requires immediate attention. The applications of drug-loaded nano-systems have shown considerable improvements in controlling PAH compared to plain drugs. The purpose of this current investigation was to prepare and characterize sildenafil-encapsulated polyethylene glycol (PEGylated) liposomes for effective treatment of pulmonary arterial hypertension. Liposomes were prepared using thin film hydration method by varying the concentrations of sildenafil, Phospholipon 90-G, cholesterol, mPEG-DSPE 2000 to optimize the formulation. The optimized liposomal formulation had mean hydrodynamic diameter, polydispersity index (PDI), zeta potential (ZP) and %EE of 155.3 ± 3.2 nm, 0.19 ± 0.1, − 42.2 ± 0.3 mV and 75.89 ± 0.5%. Transmission electron microscopy (TEM) revealed that liposomes were spherical and homogenously dispersed. FTIR (Fourier transform infrared spectroscopy) and DSC (Differential scanning calorimetry) confirmed that there was no covalent interaction between the drug and excipients. The release of sildenafil from PEGylated liposomes was found to be sustained compared to free drug. Ex vivo study in the rats showed improved vasorelaxant response for sildenafil loaded liposomes (132. 7 ± 0.7%) compared to pure sildenafil (108.2 ± 0.06%) and marketed Revatio® (113.2 ± 0.8%). In summary, sildenafil loaded PEGylated liposomes produced an impressive vasorelaxant response in rat aortic stip assay and require validation to bring the formulation available for clinical studies in the management of PAH.