Next, further investigations of the

Next, further investigations of the in vivo efficacy of compound 15a and valnemulin wereconducted in another panel mice infected by MRSA. As shown in Fig. 3, once daily intragastric (i.g.)administration with 40mg/kg of 15a and valnemulin for consecutive 3 days proffered notableprotection against lethal challenge caused by clinical isolate S.aureus resistant strain. During thetreatment period, the survival percentage of both 15a and valnemulin kept higher than 90% and thefigure experienced a slight decrease between the fifth and sixth days, standing at 70% and 80% at last,respectively. However, when the treatment dose reduced to 20 mg/kg, the survival percent of both 15aand valnemulin slumped to 30%. The rapid decrease in the survival rate intrigued by the half reductionof dose may attribute to the apparent first-pass effect of 15a and valnemulin, which lowered theeffective plasma concentration. The outcome indicates that the survival percent of infected mice issignificantly dose-dependent with the dose of both valnemulin and 15a via i.g. administration in thisexperiment model.