Aim To investigate the relationship between pH environment of meptazinolhydrochloride (MEP) and its nasal absorption. Methods In situ nasal peifusion was performed to studythe effect of pH environment on the nasal absorption. Its effect on the transport from nose tobrain was further researched by in vivo experiment. Results In in situ perfusion experiment, thenasal absorption of MEP in basic environment was significantly higher than that in acid condition,but the difference was not observed in in vivo experiment. Conclusion The pH environment ofmeptazinol hydrocloride in formulation cannot be regarded as an important factor influencing nasalabsorption and transport from nose to brain.
