Eudragit S100 prepared pH-responsive liposomes-loaded betulinic acid against colorectal cancer in vitro and in vivo

This study aimed to develop polymer Eudragit S100 for preparing pH-responsive liposomes-loaded betulinic acid (pH-BA-LP) to improve the therapeutic index of chemotherapy for colorectal cancer. BA-loaded liposomes were coated with Eudragit S100 by a thin film dispersion and easily scalable pH-driven method. The prepared liposomes were evaluated for size, surface morphology, entrapment efficiency, stability, in vitro drug release, and antitumor activity. In particular, pH-BA-LP showed advantages such as lower size (<100 nm), encapsulation efficiency of 90%, high stability, and stably cumulative release.

By detecting the antitumor effects of pH-BA-LP in vivo, it showed that the tumor proliferation and cell migration were significantly inhibited in colorectal cancer. The pH-BA-LP also inhibited tumor growth via the regulation of Akt/TLR-mediated signalling and significantly down-regulated the expression of NFAT1 and NFAT4 proteins. It was found that pH-BA-LP can increase NK cells and CD3⁺ cells in tumor tissues, and the proportion of CD8⁺ cells in CD3⁺ cells was also increased, which proved that pH-BA-LP can play an antitumor effect by enhancing the autoimmunity level in tumor-bearing mice.

The positive infiltration rates of CD8 and CD68 were increased and CD163 was relatively decreased by using pH-BA-LP, which proved that pH-BA-LP can regulate the immune infiltration levels in tumor-bearing mice. Therefore, the present work provides an effective method to prepare pH-responsive polymer-coated liposomes for colonic delivery with biologically active compounds.

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Article information: Gang Wang, Yu Yang, Du Yi, Lu Yuan, Pei-Hao Yin, Xu Ke, Wang Jun-Jie & Min-Fang Tao (2021) Eudragit S100 prepared pH-responsive liposomes-loaded betulinic acid against colorectal cancer in vitro and in vivo, Journal of Liposome Research, DOI: 10.1080/08982104.2021.1999974