The aim of the study was to prepare enrofloxacin nanosuspension injection and evaluate its pharmacokinetics after giving a single intramuscular injection.The high pressure homogeneous technique was used to prepare enrofloxacin nanosuspension injection and preliminary evaluation of the quality was done.The high performance liquid chromatography (HPLC) method was used to determinate content of enrofloxacin in pig plasma.And the pharmacokinetic characteristics of enrofloxacin nanosuspension injection were compared with Baytril injection.The content of enrofloxacin in this preparation is 97.9％.The average particle size of enrofloxacin nanosuspension injection was (613.21±5.78) nm,PDI was (0.22±0.02) and the potential was-2.02 mV.Maximal plasma concentrations were (0.32±0.12) and (0.67 ± 0.09) mg/L after i.m administration with enrofloxacin nanosuspension injection and Baytril injection.The peak times were (2.88 ±0.96) and (0.79±0.26) hours,respectively.Mean elimination half-lifes were (5.99± 1.37) and (4.49 ± 1.25) hours,respectively.Areas under concentration-time curve were (4.63±1.30) and (4.40±0.45) mg/L · h,respectively.Mean residence times were (9.59±2.34) and (5.41±1.10) hours,respectively.The relative bioavailability of enrofloxacin nanosuspension injection was 105.2％.The preparation method of high pressure homogeneous was simple and good reproducibility.Enrofloxacin nanosuspension injection was characterized by non-sedimentation,easy-redispersion,relatively stable.Comparing with Baytril injection,enrofloxacin nanosuspension injection had a certain slowrelease effect,showing slower elimination than enrofloxacin injeetion.

In recent years,studies have shown that inflammation is an important factor in secondaryischemic injury.The exploration of the related mechanisms of the occurrence of inflammation has become ahot spot in the field of cerebral ischemia.Toll-like receptor 4 (TLR4) signaling pathway is one of theclassical inflammatory pathways.Studies have shown that TLR4 is involved in the early inflammatoryresponse after cerebral ischemic injury and the late nerve repair.This article reviews the research progress ofthis signaling pathway in cerebral ischemia injury,so as to seek a therapeutic target against inflammatoryinjury caused by cerebral ischemia through the analysis of its potential research direction.