Development and characterization of pH-sensitive zerumbone-encapsulated liposomes for lung fibrosis via inhalation Route

Zerumbone (ZER), a compound derived from the rhizome of Zingiber Zerumbet (L.) Smith, has demonstrated anti-inflammatory properties but suffers from poor water solubility, limiting its clinical application. While ZER's effects on lung inflammation are known, its role in lung fibrosis remains unexplored. Herein, ZER was encapsulated in pH-sensitive liposomes formulated with oleic acid, dipalmitoylphosphatidylcholine, and cholesterol to enhance ZER solubility and delivery to the acidic environment of lung fibrosis. The liposomes were optimized using Box-Behnken design, resulting in an average diameter of 87.8 ± 3.5 nm, a polydispersity index of 0.16 ± 0.2, and a zeta potential of -24 ± 0.32 mV. ZER release from the carrier followed zero-order kinetics and showed higher release in acidic settings. Cascade impactor and HPLC analyses confirmed that ZER liposome powder produced by freeze-drying reached stage 7, indicating effective delivery to deep lung regions. The uptake of ZER liposomes was concentration and pH-dependent, being higher in acidic conditions and greater in MRC-5 cells compared to A549 cells. Notably, ZER liposomes reduced cell migration and downregulated fibrotic markers such as fibronectin, MMP-2, and α-SMA in MRC-5 and A549 cells. This study suggests that ZER liposomes hold promise for treating lung fibrosis and merit further investigation.