Intranasal Liposomal Trimetazidine Nanocarriers Modulate Neuroinflammation and Neurotransmission via the HMGB1/TLR4/NF-κB Pathway in an Experimental Epilepsy Model.

Frequent convulsions are a hallmark of the neurological disorder "epilepsy," which calls for long-term anticonvulsant medication treatment. Traditional antiseizure medications primarily modulate neurotransmitter systems or ion channels but do not address the underlying neuroinflammation and metabolic dysfunctions that contribute to epileptogenesis. Trimetazidine (TMZ), a cytoprotective agent, has shown potential in reducing seizures at higher doses, but its bioavailability and therapeutic efficacy can be enhanced through intranasal nanoliposomal delivery. This study investigates the formulation, optimization, and evaluation of TMZ-loaded Liposomal Nanocarriers (NTMZ) for enhanced anticonvulsant, antioxidant, and anti-inflammatory effects. NTMZ was designed and optimized using a Box-Behnken design to evaluate the effects of phospholipid concentration, surfactant percentage, and sonication time on particle size, polydispersity index (PDI), and encapsulation efficiency (EE%). The formulations were characterized by dynamic light scattering, transmission electron microscopy (TEM), differential scanning calorimetry (DSC), and Fourier transform infrared (FTIR) spectroscopy. In vitro release, ex vivo permeation studies, and antioxidant activity assays were conducted. Pharmacological efficacy was evaluated through pentylenetetrazol (PTZ)-induced kindling and increasing current electroshock seizure (ICES) models in Swiss Albino mice. Biochemical analysis of inflammatory markers (IL-1β, IL-6, TNF-α), neurotransmitter levels (GABA, glutamate), and neuroinflammatory signaling (NF-κB, HMGB1-TLR4) was also performed. NTMZ displayed a particle size of 241.9 nm, a PDI of 0.465, and an entrapment efficiency of 87%. In vitro release showed an initial burst release of 62% in 8 h, followed by sustained release over 24 h. TEM analysis confirmed uniform spherical morphology, and stability tests indicated robust formulations. In vivo studies revealed that 5 mg NTMZ significantly outperformed standard TMZ in PTZ and ICES models, reducing seizure severity and cognitive deficits. NTMZ also suppressed neuroinflammatory markers (IL-1β, IL-6, TNF-α, HMGB1, TLR4, and NF-κB), enhanced GABAergic neurotransmission, and lowered glutamate levels. These findings demonstrate the potential of intranasal delivery of NTMZ as a novel formulation for managing epilepsy through its improved bioavailability, reduced dose, sustained release, and potent neuroprotective properties. Simultaneously, pharmacological modulation of neuroinflammation and neurotransmitters were observed.