Improved Biopharmaceutical Performance of Coenzyme Q10 Through Solid Lipid Nanoparticles for Enhanced Brain Delivery

Coenzyme Q10 (CoQ) is a powerful antioxidant with neuroprotective characteristics; nevertheless, its clinical use is constrained by inadequate solubility, diminished bioavailability, and limited blood-brain barrier (BBB) penetration. Solid lipid nanoparticles (SLNs) offer a promising approach to improve the biopharmaceutical characteristics and targeted delivery of CoQ to the brain. This study focuses on the strategic formulation and optimization of SLN-CoQ to improve solubility, oral absorption, and BBB permeability. The SLNs with drug loading of 2.5% (w/w) were prepared using a solvent injection technique and physicochemically characterized employing encapsulation efficiency, drug loading, particle size, zeta potential, surface morphology, crystallinity, in vitro drug release behavior, and mucus penetrating behavior. Pharmacokinetic studies were conducted in rats (100 mg-CoQ/kg, p.o.) after oral administration to elucidate the possible enhancement in the oral absorption of CoQ. The SLN-CoQ (F2) exhibited favorable physicochemical characteristics, including optimal particle size (91.6 ± 8.2 nm), zeta potential (-41.7 ± 1.03 mV), high encapsulation efficiency (85.2 ± 5.0), distinct surface morphology, reduced crystallinity, enhanced drug release, and better mucus penetration than crystalline CoQ. In the dissolution test, SLN-CoQ demonstrated a significant enhancement in the dissolution profile of CoQ as exhibited by an 83.6-fold higher dissolved amount of CoQ in 120 min in water in the F2 formulation ratio. Moreover, in the artificial mucus test, a 42-fold increase in mucus permeation was observed for the F2 formulation compared to the crystalline drug. Orally administered CoQ exhibited a higher systemic exposure of CoQ (3.6-fold higher) in SLLN-CoQ compared to crystalline CoQ, with prolonged circulation time and improved tissue distribution (3-fold higher) in rats. The findings suggest that SLN-CoQ offers a feasible nanotechnological method for enhanced drug transport to the brain, potentially aiding therapeutic approaches for neurodegenerative diseases, including Parkinson's and Alzheimer's.