Organelle-targeted nanostructured lipid carriers: Strategic design, analytical validation, and translational insights for precision intracellular drug delivery

Abstract

Precision intracellular drug delivery, enhanced payload capacity, physicochemical stability, and tunable release kinetics are the features offered by nanostructured lipid carriers (NLCs) as a next-generation drug delivery platform. Organelle-specific engineering and rational design of NLCs for targeted delivery to subcellular compartments, including the mitochondria, lysosomes, nucleus, endoplasmic reticulum (ER), and Golgi apparatus, are comprehensively discussed in this review. Strategic physicochemical modifications, such as particle size optimisation, surface functionalization with targeting ligands (e.g., TPP, TAT, NLS, KDEL), ceramide-mimetic components, and incorporation of pH or redox-responsive lipids, achieve organelle-specific localization, enabled by coupling chemistries like bio-orthogonal click reactions and EDC/NHS activation. High-resolution imaging modalities (CLSM, TEM, cryo-EM), co-localization quantification (Pearson's and Mander's coefficients), LC-MS/MS, FERT, FRAP, imaging flow cytometry, and differential scanning calorimetry (DSC) are used to validate targeting efficiency and formulation integrity analytically. Particle size, zeta potential, encapsulation efficiency, crystallinity, and release behavior are included in critical quality attributes (CQAs) that are optimised systematically using Design of Experiment (DoE) within a quality-by-design (QbD) framework. Physiologically based pharmacokinetics (PBPK) modelling and spatial lipidomics for assessing biodistribution and pharmacodynamic impact are used as preclinical translation, incorporating bioanalytical method validation. Endosomal entrapment, interspecies variability, and GMP-compliant challenges are the key translational and regulatory bottlenecks addressed in this review. Transformative potential for NLC-based precision medicine includes converging dual-organelle targeting, multi-stimuli responsiveness, emerging AI-guided design tools, and continuous manufacturing platforms. Redefining the landscape of intracellular therapeutics towards clinically viable organelle-targeted formulations through cutting-edge innovations is consolidated in this review.