Pharmacokinetics and antimalarial activities of reduction-responsive releasing dihydroartemisinin prodrug self-assembled nanoparticles in rodents

Design of red blood cell membrane-cloaked dihydroartemisinin nanoparticles with enhanced antimalarial efficacy

Targeting delivery and prolonging action duration of artemisinin drugs are effective strategies for improving antimalarial treatment outcomes. Here, dihydroartemisinin (DHA) loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (PDNs) were prepared and further cloaked with red blood cell (RBC) membranes via electrostatic interactions to yield RBC membrane-cloaked PDNs (RPDNs). The prepared RPDNs displayed a notable "core-shell" structure, with a negative surface charge of -29.2 ± 4.19 mV, a relatively uniform size distribution (86.4 ± 2.54 nm, polydispersity index of 0.179 ± 0.011), an average encapsulation efficiency (70.1 ± 0.79%), and a 24-h sustained-release behavior in vitro. Compared with PDNs, RPDNs showed markedly decreased phagocytic activity by RAW 264.7 cells and had prolonged blood circulation duration. The Pearson correlation coefficient of RPDNs distribution in infected red blood cells (iRBCs) was 0.7173, suggesting that RPDNs could effectively target Plasmodium-iRBCs. In PyBy265-infected mice, RPDNs showed a higher inhibition ratio (88.39 ± 2.69%) than PDNs (83.13 ± 2.12%) or DHA (58.74 ± 3.78%), at the same dose of 8.8 μmol/kg. The ED₉₀ of RPDNs (8.13 ± 0.18 μmol/kg) was substantially lower than that of PDNs (14.48 ± 0.23 μmol/kg) and DHA (17.67 ± 3.38 μmol/kg). Furthermore, no apparent abnormalities were detected in routine blood examination, liver function indexes, and pathological analysis of tissue sections of PyBy265-infected mice following RPDNs treatment. In conclusion, the prepared RPDNs exhibited enhanced antimalarial efficacy, prolonged circulation, targeted delivery to Plasmodium-iRBCs, and satisfactory biocompatibility.

Murine pharmacokinetics and antimalarial pharmacodynamics of dihydroartemisinin trimer self-assembled nanoparticles

Currently, conjugation of artemisinin-derived dimers, trimers, and tetramers is a viable strategy for developing new effective antimalarial candidates. Furthermore, nanotechnology is an effective means to achieve intravenous administration of hydrophobic drugs. In this paper, an ester-linked dihydroartemisinin trimer (DHA₃) was synthesized and further prepared as self-assembled nanoparticles (DHA₃NPs) by a one-step nanoprecipitation method. The pharmacokinetics and antimalarial pharmacodynamics of DHA₃NPs were studied in rats and mice infected with Plasmodium yoelii BY265 (PyBY265). DHA₃NPs had a regular spherical shape with a uniform size distribution of 140.27 ± 3.59 nm, entrapment efficiency (EE) of 99.63 ± 0.17%, and drug loading efficiency (DL) of 79.62 ± 0.11%. The in vitro release characterization revealed that DHA₃NPs were easily hydrolysed into DHA in an esterase environment. The pharmacokinetics study demonstrated that the area under the concentration-time curve (AUC_0-t) of DHA in DHA₃NPs group was 2070.52 ± 578.76 h×ng×mL^-1, which was higher than that of DHA and artesunate (AS) control groups (AUC_0-t values of 724.18 ± 94.32 and 448.40 ± 94.45 h×ng×mL^-1, respectively) (P < 0.05). The antimalarial pharmacodynamics in vivo suggested that DHA₃NP_S (ED₉₀ 7.82 ± 1.16 μmol×(kg×day)^-1) had a superior antimalarial effect compared with that of control groups (ED₉₀ values of 14.68 ± 0.98 (DHA) and 14.34 ± 1.96 (AS) μmol×(kg×day)^-1) (P < 0.05). In addition, DHA₃NP_S reduced the recurrence ratio and improved the cure ratio and survival time. In summary, DHA₃NPs exhibited promising pharmacokinetic characteristics and antimalarial pharmacodynamics in vivo.