Investigating Hybrid PLGA-Lipid Nanoparticles as an Innovative Delivery Tool for Palmitoylethanolamide to Muscle Cells

Background/Objectives: Palmitoylethanolamide (PEA) is an endogenous lipid mediator with endocannabinoid-like activity. Despite its therapeutic potential in muscle-related in- flammatory disorders, including sarcopenia, its clinical use is limited by poor solubility and bioavailability. To overcome these issues, we developed hybrid nanoparticles com- bining poly(lactic-co-glycolic acid) (PLGA) and lipids to enhance PEA encapsulation and ok delivery. Methods: PEA-loaded hybrid nanoparticles (PEA-Hyb-np) were produced via a modified single-emulsion solvent evaporation method using stearic acid and Ge- lucire® 50/13 as lipid components. Characterization included particle size, morphology, PDI, and zeta potential, as well as DSC, FT-IR, and XRD analyses. For the biological eval- uation in a C2C12 myoblasts cell culture, coumarin-6-labeled nanoparticles were em- ployed. Results: PEA-Hyb-np showed mean particle sizes of ~150 nm, with internal lipid– polymer phase separation. This structure enabled high encapsulation efficiency (79%) and drug loading (44.2 mg/g). Drug release in physiological and non-physiological media was enhanced due to drug amorphization, confirmed by DSC, FT-IR, and XRD analyses. Cy- tocompatibility studies showed no toxicity and improved cell viability compared to un- loaded nanoparticles. Cellular uptake studies by confocal microscopy and flow cytometry demonstrated efficient and time-dependent internalization. Conclusions: PEA-Hyb-np represent a promising delivery platform to improve the solubility, bioavailability, and therapeutic efficacy of PEA for muscle-targeted applications.