Eicosapentaenoic Acid As a Bioactive Liquid Lipid in Methotrexate-Loaded Nanostructured Lipid Carriers Publisher



Moghimipour E ; Salimi A ; Handali S ; Dayer D ; Malayeri A ; Kaydan H H ; Javadiyeh A
Source: Jundishapur Journal of Natural Pharmaceutical Products Published:2026

Abstract

Background: Nanostructured lipid carriers (NLCs) are promising vehicles for the topical delivery of poorly permeable drugs such as methotrexate (MTX). In conventional NLCs, the liquid lipid serves primarily as a structural component, whereas incorporating a bioactive natural liquid lipid may provide additional formulation benefits for the resulting carrier. Objectives: This study aimed to design and physicochemically characterize MTX-loaded NLCs using eicosapentaenoic acid (EPA), a natural omega-3 fatty acid, as a bioactive liquid lipid, and to identify an optimal formulation through a systematic two-level formulation design. Methods: Eight formulations were prepared by hot emulsification followed by sonication, with varying amounts of solid lipid (stearic acid), liquid lipid (EPA), and surfactant (soya lecithin). The MTX assay was validated by reversed-phase high-performance liquid chromatography (HPLC) for linearity, limit of detection (LOD), limit of quantification (LOQ), precision, selectivity, and matrix-matched recovery. The formulations were characterized in terms of particle size, polydispersity index (PDI), zeta potential, entrapment efficiency (EE%), drug loading (DL%), and in vitro release. The release kinetics of the optimal formulation were evaluated using four models (zero-order, first-order, Higuchi, and Korsmeyer-Peppas), and physical stability was monitored for three months. Results: The HPLC method was linear over 1 - 20 µg/mL (R2 = 0.9981), with LOD and LOQ of 1.56 and 4.72 µg/mL, respectively, and precision of RSD ≤ 2%. Particle size ranged from 88.92 to 160.7 nm, and PDI ranged from 0.252 to 0.405. The optimal formulation (F5; stearic acid 200 mg, EPA 20 mg, lecithin 40 mg) showed a particle size of 88.92 nm, a PDI of 0.284, a zeta potential of ‒18.5 mV, an EE% of 88.40%, and a DL% of 7.89%. Its 24 h cumulative release reached 88.03%; among the tested models, the release best fit the Korsmeyer-Peppas (R2 = 0.987; n = 1.12) and first-order (R2 = 0.977) models, indicating a coupled diffusion–relaxation mechanism. All formulations remained physically stable over three months. Conclusions: EPA can serve as a bioactive liquid lipid in NLCs, producing nanoscale carriers with high entrapment, adequate drug loading, and sustained release. These findings provide a robust physicochemical basis for topical MTX carriers; however, biological and skin-delivery validation is required before any therapeutic benefit of EPA can be claimed. Copyright © 2026, Moghimipour et al.