OBJECTIVE To screen a single matrix， prepare dissolving microneedles of Pterocarya hupehensis total flavonoids（PHTF-MN）， and characterize it while evaluating its analgesic effects.METHODS Using microneedle morphology and puncture rate as evaluation indicators， the matrix was screened from polyvinyl alcohol （PVA）， polyvinylpyrrolidone K30 （PVP K30）， PVP K90， and sodium hyaluronate with relative molecular weights of 15 000 and 60 000 （HA 1.5w and HA 6w ）. PHTF-MN was prepared by the layer-by-layer casting method with the selected matrix， and the appearance and morphology， total flavonoid content， mechanical properties， puncture performance， dissolution properties， and drug release behavior of the obtained PHTF-MN were characterized. Using male BALB/c mice as test subjects and aspirin （ASA） as a positive control， the analgesic effects of the microneedles were evaluated using a formalin-induced pain model.RESULTS Blank microneedles prepared with 30% HA 1.5w exhibited optimal surface flatness and the membrane puncture rate （through 4 layers of parafilm membrane） reaching 78%. The PHTF-MNs （with PHTF contents of 10， 20， 30， 40， and 50 mg/g in the matrix） exhibited uniform arrays and intact tips， with RSDs for total flavonoid contents all below 7% （ n ＝8）. The single-needle puncture forces were 1.46 and 1.07 N （with PHTF contents of 30 and 50 mg/g in the matrix， respectively）. The skin penetration rate approached 100%， with visible puncture marks in the stratum corneum and drug residue （with a PHTF content of 50 mg/g in the matrix）. After 30 min of fixation， the needles had almost completely dissolved， and the skin retention rates all exceeded 90% （with PHTF contents of 10， 30， and 50 mg/g in the matrix， respectively）. The cumulative release within 8 h was （134.64±2.03） μg/cm 2 ， and the fit to the first-order kinetic equation （ R 2 ＝0.950 1） was highest （with a PHTF content of 50 mg/g in the matrix）. Low- and high-dose PHTF-MN （containing 85.26 and 145.03 μg of total flavonoids per patch， respectively； 1 patch/day） significantly shortened the cumulative time of phase Ⅱ pain response in mice （ P ＜0.05）， with pain inhibition rates （43.67% and 59.78%） comparable to those of ASA （53.70%）.CONCLUSIONS PHTF-MN using HA 1.5w as a single matrix was successfully prepared. This formulation features a simplified preparation process， uniform drug loading， favorable mechanical properties， resistance to fracture， and rapid dissolution. Its drug release behavior conforms to a first-order kinetic model， and its analgesic effect is comparable to that of ASA.

Animals ; Antibodies, Neutralizing/biosynthesis* ; Antibodies, Viral/biosynthesis* ; Body Weight/immunology* ; COVID-19/virology* ; Disease Models, Animal ; Disease Progression ; Humans ; Immunohistochemistry ; Lung/virology* ; Male ; Mesocricetus ; Nasal Cavity/virology* ; RNA, Viral/immunology* ; SARS-CoV-2/pathogenicity* ; Severity of Illness Index ; Viral Load