Tofacitinib-Loaded Nanostructured Lipid Carriers: Formulation, Characterization and In Vitro Release

Tofacitinib is an orally administered Janus kinase inhibitor. Nanostructured lipid carriers (NLCs) combine solid and liquid lipids and may alter drug dispersion, association and release in the gastrointestinal environment. This study examined a tofacitinib-loaded NLC system. Candidate lipids and surfactants were screened, and five batches (F1–F5) containing glyceryl monostearate (solid lipid) and oleic acid (liquid lipid) were compared. Dispersions were prepared by high-pressure homogenization and/or ultrasonication. Particle size, polydispersity index (PDI), zeta potential and entrapment efficiency were measured; compatibility and solid-state behavior were examined by FTIR, DSC and XRD. In vitro release, three-month colloidal stability and a summarized oral pharmacokinetic comparison were evaluated. Batch F5 showed a mean particle size of 118.5 nm, PDI of 0.198, zeta potential of −32.1 mV and entrapment efficiency of 88.9%. Cumulative release at 24 h was 96.5% for F5 and 82.1% for pure drug, with the Higuchi model giving the best fit (R² = 0.987). After three months, particle size, entrapment efficiency and zeta potential changed from 118.5 to 125.2 nm, from 88.9% to 86.7% and from −32.1 to −30.4 mV, respectively. Reported Cmax values were 3.9 µg/mL (NLC) and 1.8 µg/mL (pure drug), and AUC values were 29.8 and 12.4 (units not stated). A tofacitinib-containing NLC dispersion with favorable colloidal properties and greater in vitro release than pure drug was prepared. The pharmacokinetic difference is preliminary and requires confirmation with complete, dose-normalized data.