文献：a novel local anesthetic system: transcriptional transactivator peptide-decorated nanocarriers for skin delivery of ropivacaine

文献链接：https://www.dovepress.com/a-novel-local-anesthetic-system-transcriptional-transactivator-peptide-peer-reviewed-fulltext-article-DDDT

作者：chuanyu chen，Peijun You

相关产品：PLGA-PEG-Mal（聚乳酸-羟基乙酸共聚物-聚乙二醇-马来酰亚胺）

原文摘要：

Purpose: Barrier properties of the skin and physicochemical properties of drugs are the main

factors for the delivery of local anesthetic molecules. The present work evaluates the anesthetic efficacy of drug-loaded nanocarrier (NC) systems for the delivery of local anesthetic drug, ropivacaine (RVC).

Methods: In this study, transcriptional transactivator peptide (TAT)-decorated RVC-loaded NCs (TAT-RVC/NCs) were successfully fabricated. Physicochemical properties of NCs were determined in terms of particle size, zeta potential, drug encapsulation efficiency, drug-loading capacity, stability, and in vitro drug release. The skin permeation of NCs was examined using a Franz diffusion cell mounted with depilated mouse skin in vitro, and in vivo anesthetic effect was evaluated in mice.

Results: The results showed that TAT-RVC/NCs have a mean diameter of 133.2 nm and high drug-loading capacity of 81.7%. From the in vitro skin permeation results, it was observed that transdermal flux of TAT-RVC/NCs was higher than that of RVC-loaded NCs (RVC/NCs) and RVC injection. The evaluation of in vivo anesthetic effect illustrated that TAT-RVC/NCs can enhance the transdermal delivery of RVC by reducing the pain threshold in mice.

Conclusion: These results indicate that TAT-decorated NCs systems are useful for overcoming the barrier function of the skin, decreasing the dosage of RVC and enhancing the anesthetic effect. Therefore, TAT-decorated NCs can be used as an effective transdermal delivery system for local anesthesia.   

PLGA-PEG-Mal：PLGA 是聚乳酸 - 羟基乙酸共聚物（Poly (lactic - co - glycolic acid)），它由乳酸和羟基乙酸聚合而成，乳酸有不同的旋光异构体，如 L - 乳酸和 D - 乳酸。PEG 是聚乙二醇（Polyethylene glycol），具有良好的水溶性和生物相容性，能够改善材料的亲水性和在生物体内的稳定性。Mal 是马来酰亚胺（Maleimide）基团，它含有碳 - 碳双键，能与含有巯基（- SH）的化合物发生特异性的迈克尔加成反应。PLGA - PEG - Mal 是一种三嵌段共聚物，PLGA 和 PEG 通过化学键连接，马来酰亚胺基团位于分子链的一端。这种结构使得它兼具了 PLGA 的可生物降解性、PEG 的良好亲水性和生物相容性以及 Mal 基团的化学反应活性。基于PLGA-PEG-Mal的性能特点，TAT-RVC/NCs的合成如下：

图：PLGA-PEG-Mal结构式

TAT-PEG-PLGA的合成：

将 PLGA-PEG-Mal， Cys-TAT和三乙胺在氯仿中反应，室温下温和搅拌。然后用一定截止量（MWCO）膜对妖魔化水透析溶剂。然后将该产品冻干以使用。采用薄层色谱（TLC）检测反应过程。薄层色谱证实PLGA-PEG-Mal点消失，TAT-PEG-PLGA的形成。

TAT-RVC/NCs的合成：

在制备NCs之前，将盐酸RVC一水合物与摩尔量的三乙胺在二甲基亚砜（DMSO）中搅拌，得到亲脂性RVC碱。将 TAT-PEG-PLGA和 RVC溶解在丙酮中。将有机相滴加到所需的稳定水中，在实验室用磁力搅拌器在室温下搅拌使有机溶剂完全蒸发。然后，通过超离心收集TAT-RVC/ nc，并在超纯水中重悬。然后，收集上清并用超纯水洗，在磷酸盐缓冲盐水（PBS）中，通过膜过滤，并使用甘露醇作为冷冻保护剂进行冻干。采用相同的方法，用PLGA-PEG代替TAT-PEG-PLGA制备非tat修饰的RVC- NCs。同样方法制备空白nc细胞，不加RVC。

图：产品结构示意

结论：

该文献成功制备出基于PLGA-PEG-Mal合成的TAT-RVC/NCs。实验证明，TAT-RVC/NCs具有高载药能力，其经皮通量高于RVC负载的NCs（RVC/NCs）和RVC注射液，并且可以通过降低疼痛阈值来增强RVC的经皮传递。结果表明，TAT修饰的NCs可以作为一种局部透皮作用系统。