Liposomal remdesivir inhalation solution for targeted lung delivery as a novel therapeutic approach for COVID-19

Strong infectivity enables coronavirus disease 2019(COVID-19)to rage throughout the world.Moreover,the lack of drugs with definite therapeutic effects further aggravates the spread of the pandemic.Remdesivir is one of the most promising anti-severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)drugs.However,the limited clinical effects make its therapeutic effect controversial,which may result from the poor accumulation and activation of remdesivir in the lung.Therefore,we developed lyophilized remdesivir liposomes(Rdv-lips)which can be reconstituted as liposomal aerosol for pulmonary delivery to improve the in vivo behavior of existing remdesivir cyclodextrin conclusion compound(Rdv-cyc)injections.Liposome encapsulation endowed remdesivir with much higher solubility and better biocompatibility.The in vitro liposomal aerosol characterization demonstrated that Rdv-lips possessed a mass median aerodynamic diameter of 4.118μm and fine particle fraction(<5μm)higher than 50%,indicating good pulmonary delivery properties.Compared to the Rdv-cyc intravenous injection group,the Rdv-lips inhalation group displayed a nearly 100-fold increase in the remdesivir-active metabolite nucleotide triphosphate(NTP)concentration and better NTP accumulation in the lung than the Rdv-cyc inhalation group.A faster transition from remdesivir to NTP of Rdv-lips(inhalation)could also be observed due to better cell uptake.Compared to other preparations,the superiority of Rdv-lips was further evidenced by the results of an in vivo safety study,with little possibility of inducing inflammation.In conclusion,Rdv-lips for pulmonary delivery will be a potent formulation to improve the in vivo behavior of remdesivir and exert better therapeutic effects in COVID-19 treatment.