A Review on Liposomal Nanocarriers for Improving Bioavailability of Poorly Soluble Drugs

Review Article

Abstract

Inadequate aqueous solubility severely hampers the therapeutic efficacy and clinical use of a substantial proportion of newly discovered chemical moieties and established active pharmaceutical ingredients. Encapsulation of hydrophobic molecules within liposomal nanocarriers provides a structurally flexible methodology to overcome dissolution-rate limited absorption, chemical degradation, and systemic toxicity. Phospholipid bilayers host lipophilic molecules within their acyl chains while aqueous cores accommodate hydrophilic moieties, forming biocompatible vesicular assemblies that mimic biological membranes. Enhanced oral and parenteral bioavailability stems from increased apparent solubility, augmented intestinal mucosal permeability, protection against enzymatic hydrolysis, and preferential uptake through the lymphatic vasculature. Selection of fabrication technology like thin-film hydration, reverse-phase evaporation, ethanol injection, and high-pressure microfluidization directly governs critical quality attributes such as hydrodynamic diameter, polydispersity index, surface charge, and entrapment efficiency. Physicochemical characterization utilizing dynamic light scattering, electron microscopy, and in vitro release kinetics establishes the structural integrity and stability profiles necessary for therapeutic performance. Advanced surface functionalization, including polyethylene glycol coating and target-specific ligand conjugation, extends circulation half-life and achieves preferential accumulation in diseased tissues. Clinical applications in oncology, infectious disease management, vaccine adjuvantation, and nucleic acid transport validate the capacity of liposomes to widen therapeutic windows and minimize systemic adverse effects