目的　研究盐酸美普他酚制剂中pH和鼻腔吸收之间的关系。方法　通过鼻腔在体循环试验考察不同pH环境对盐酸美普他酚鼻腔吸收的影响 ,并利用体内试验考察模型药物经鼻入脑的情况。结果　鼻腔在体循环试验发现盐酸美普他酚在碱性条件下吸收显著优于酸性条件 ,但是在体内试验中发现不同pH环境对药物吸收入脑并没有显著性差异。结论　制剂中的pH环境对盐酸美普他酚鼻腔吸收和入脑无显著影响 Objective To study the relationship between pH and nasal absorption in meptazin hydrochloride preparations. Methods Nasal cavity was used to study the influence of pH environment on nasal absorption of meptazinol hydrochloride in systemic circulation test. Results In the systemic circulation, the nasal cavity was found to have significantly better absorption of meptazinol in alkaline conditions than in acidic conditions, but no significant difference in absorption of drug into the brain at different pH conditions was found in in vivo studies. Conclusion The pH environment in the formulation had no significant effect on intranasal absorption and inclusion into the brain of meptazin hydrochloride