An in vitro study for reducing the cytotoxicity and dose dumping risk of remdesivir via entrapment in nanostructured lipid carriers

The aim of this study was to synthesize and evaluate nanostructured lipid carriers (NLCs) loaded with Remdesivir (RDV) to control its side effects in COVID-19 patients. Due to the low solubility and short half-life of RDV in the blood, an injectable formulation was prepared using sulphobutylether-beta-cyclodextrin. However, it can accumulate in the kidney and cause renal impairment. NLCs improve the parenteral delivery of hydrophobic drugs such as RDV by increasing drug solubility and bioavailability. For the synthesis of RDV-NLCs, the aqueous phase containing Tween 80 was injected into the lipid phase under rapid stirring and was sonicated. The experimental conditions were optimized using Box-Behnken design and Design Expert software. The optimum formulation contained a total lipid of 2.13%, a total surfactant of 1%, and a hot bath time of 71 min. The optimum formulation showed particle size, polydispersity index, zeta potential, and entrapment efficiency values of 151.0 +/- 1.7 nm (from 149.1 to 152.1), 0.4 +/- 0.1 (from 0.3 to 0.5), -43.8 +/- 1.2 mV (from -42.4 to -44.7), and 81.34 +/- 1.57% (from 79.52 to 82.33%), respectively. RDV-NLCs showed acceptable stability for 30 days at 25 degree celsius and were compatible with commonly used intravenous infusion fluids for 48 h. FE-SEM images of RDV-NLC showed spherical particles with a mean diameter of 207 nm. The NLC-RDV formulation showed a sustained release of RDV with a low risk of dose-dumping, minimizing potential side effects. In addition, RDV in the form of RDV-NLC causes less cytotoxicity to healthy normal kidney cells, which is expected to reduce renal impairment in COVID-19 patients.