Pharmacokinetic and biodistribution of hyaluronic acid (HA)-modified hybrid membrane (M)-camouflaged poly lactic-co-glycolic acid (PLGA) loaded halofuginone hydrobromide (HF) nanoparticles (NPs) (HA-M@P@HF NPs) in adjuvant-induced arthritis (AIA) rats. (A) The fluorescence images of chlorin e6 (Ce6), P@Ce6, and HA-M@P@Ce6 NPs in the blood of rats at different time points. (B) Pharmacokinetic curves of HF, P@HF, and HA-M@P@HF NPs over time determined by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). (C, D) Fluorescent distribution (C) and quantification (D) in affected joints. (E) Determination of drug concentration in major organs after 48 h post-injection by UPLC-MS/MS. Data are presented as mean ± standard deviation (n = 3). ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P < 0.001. t1/2: half-life; MFI: mean fluorescence intensity.