Dual‑loaded nanoparticles targeting inflammation as multimodal strategy against sarcopenia

Sarcopenia is rapidly emerging as a major health and social challenge, highlighting the urgent need for innovative therapeutic strategies to complement nutritional interventions and physical exercise, or to replace them when ineffective or not feasible. In this context, we propose a multimodal approach based on the combined use of Palmitoylethanolamide (PEA) and Trimetazidine (TMZ), two compounds with distinct yet potentially synergistic mechanisms of action. Previous studies from our group demonstrated promising results using PEA-loaded solid lipid nanoparticles and hybrid PLGA nanoparticles [1, 2] in C2C12 muscle cells. PEA, an endogenous fatty acid amide with well-established anti-inflammatory properties and minimal side effects, acts through the activation of PPARα. This makes PEA a suitable candidate to counteract the chronic low-grade inflammation associated with aging and considered a key driver of sarcopenia. Conversely, TMZ is a metabolic modulator that partially inhibits mitochondrial β-oxidation, shifting energy production toward glucose oxidation and improving metabolic efficiency. TMZ has been shown to enhance muscle strength in aged mice and to promote myogenesis, mitochondrial biogenesis, and respiratory chain activity [3], supporting its role as an “exercise mimetic” for individuals unable to exercise or experiencing anabolic resistance. Given their complementary actions, the co-delivery of PEA and TMZ through a single nanoparticulate system may represent an innovative therapeutic strategy. In this work, we developed hybrid PLGA nanoparticles capable of encapsulating both drugs, despite their opposite physicochemical properties (hydrophilic TMZ and lipophilic PEA). Conversion of TMZ dihydrochloride into base form and in deep characterization of the base form was carried out. We investigated different formulation techniques, including single and double emulsions, for base and dihydrochloride form of TMZ, respectively, and we assessed the stability and loading capacity of nanoparticles. Calorimetric analyses were performed to evaluate drug–matrix interactions, while encapsulation efficiency and in vitro dual-drug release was quantified via HPLC. Future work will focus on functionalizing the co-loaded nanoparticles for selective targeting of skeletal muscle and evaluating their therapeutic efficacy in preventing muscle loss in aged mice.