Investigating the passage of tetramethylpyrazine-loaded liposomes across blood-brain barrier models in vitro and ex vivo.

Abstract Tetramethylpyrazine (TMP) is a natural product extracted from Rhizoma Chuanxiong . Liposomes are an excellent delivery method that is suitable for the penetration of the blood-brain barrier (BBB). TMP-loaded liposomes are suitable for the treatment of cerebral ischemic diseases. We measured the morphology, particle size, zeta-potential, entrapment efficiency, and content of TMP-loaded liposome. The electrochemical method was adopted to determine entrapment efficiency for the first time. In addition, their diffusion through BBB models, which were built not only by in vitro cell culture but also by the ex vivo mouse subcutaneous-mucous-membrane (mSMM) method, was explored. The results showed that TMP and TMP-loaded liposomes could effectively permeate both BBB models. Therefore, the study indicated that liposomes were a novel carrier that could deliver TMP across the body barrier models and then release TMP slowly.