Development, Characterization, And In Vitro Evaluation Of Phospholipid-Based Liposomes Encapsulating Linezolid For Targeted Therapeutic Management Of Gram-Positive Bacterial Infections

Abstract

The present study aimed to design, optimize, and evaluate liposomal formulations of Linezolid for improved antibacterial efficacy and targeted drug delivery. Linezolid, a potent oxazolidinone-class antibiotic, was encapsulated in liposomes using the thin-film hydration technique followed by sonication. A series of five formulations (LZL1–LZL5) were prepared by varying the ratios of phosphatidylcholine and cholesterol to optimize particle size, polydispersity index (PDI), zeta potential, entrapment efficiency, and drug release profile. Among the developed formulations, LZL3 demonstrated optimal characteristics with a particle size of 164.3 ± 2.3 nm, PDI of 0.247, zeta potential of –27.6 ± 0.9 mV, and entrapment efficiency of 81.56 ± 2.5%. Transmission Electron Microscopy confirmed spherical and uniform vesicle morphology. In vitro release studies revealed a sustained drug release from LZL3 (88.56 ± 1.89% at 12 h), while antibacterial activity assays showed significant zones of inhibition against Staphylococcus aureus and Escherichia coli, comparable to the free drug. These findings suggest that liposomal encapsulation of Linezolid enhances its delivery and therapeutic potential while offering controlled release and improved stability. The study supports the use of liposomes as an effective platform for targeted antibiotic therapy, potentially reducing dosing frequency and systemic side effects.