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Thymopentin-loaded phospholipid-based phase separation gel with long-lasting immunomodulatory effects: in vitro and in vivo studies


Thymopentin (TP5) is an effective immunomodulatory agent for autoimmune disease that has been used clinically for decades. However, its application is greatly limited by its extremely short half-life in vivo, poor membrane permeability and extensive metabolism in gastrointestinal tract, resulting in repeated injection and poor patient compliance. In the present study, we developed a TP5-loaded, phospholipid-based phase separation gel (PPSG) to achieve sustained drug release profile and long-lasting therapeutic effects. We firstly demonstrated the physiochemical characteristics of PPSG before and after phase transition by examining the viscosity and morphology change caused by the phase transition. Moreover, the PPSG exerted a low cytotoxicity in L929 cells and HUVECs, suggesting the biocompatibility of PPSG. A month-long drug release profile of TP5 PPSG was observed both in vitro and in vivo, revealing its sustained and controlled drug release property. Most importantly, in cyclophosphamide-induced immunosuppressive rats, a single dose of TP5 PPSG (15 mg/kg, sc) injected could normalize their T-SOD levels and CD4+/CD8+ ratio; such an immunoregulatory effect was comparable to that produced by repeated injection of TP5 solution (0.6 mg/kg per day, sc) for 14 consecutive days. Thus, TP5 PPSG has a great potential for sustained delivery of TP5 in clinical use because of its simple manufacture process, good biocompatibility and long-lasting immunomodulatory efficacy, which could greatly improve patient compliance.

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  1. 1.

    Goldstein G, Audhya TK. Thymopoietin to thymopentin: experimental studies. Surv Immunol Res. 1985;4(Suppl 1):1–10.

  2. 2.

    Colle R, Ceschia T, Colatutto A, Biffoni F. Use of thymopentin in autoimmune hemolytic anemia due to chronic lymphocytic leukemia. Curr Ther Res. 1988;44:1045–9.

  3. 3.

    Sundal E, Bertelletti D. Thymopentin treatment of rheumatoid arthritis. Arzneim-Forsch. 1994;44:1145–9.

  4. 4.

    Bodey B, Bodey B, Siegel SE, Kaiser HE. Review of thymic hormones in cancer diagnosis and treatment. Int J Immunopharmacol. 2000;22:261–73.

  5. 5.

    Coppola S, Buccoliero G, Laddago V, Monno L, Perrone A, Guida G, et al. Topical thymopentin therapy in HIV positive patients with recurrent oral candidiasis: a pilot study. New Microbiol. 1996;19:351–5.

  6. 6.

    Xiaojing C, Yanfang L, Yanqing G, Fangfang C. Thymopentin improves cardiac function in older patients with chronic heart failure. Anatol J Cardiol. 2017;17:24–30.

  7. 7.

    Singh VK, Biswas S, Mathur KB, Haq W, Garg SK, Agarwal SS. Thymopentin and splenopentin as immunomodulators. Curr Status Immunol Res. 1998;17:345–68.

  8. 8.

    Kondratyev MS, Lunin SM, Kabanov AV, Samchenko AA, Komarov VM, Fesenko EE, et al. Structural and dynamic properties of thymopoietin mimetics. J Biomol Struct Dyn. 2014;32:1793–801.

  9. 9.

    Gonser S, Weber E, Folkers G. Peptides and polypeptides as modulators of the immune response: thymopentin--an example with unknown mode of action. Pharm Acta Helv. 1999;73:265–73.

  10. 10.

    Audhya TK, Goldstein G. Thymopentin: stability considerations and potency by various routes of administration. Surv Immunol Res. 1985;4(Suppl 1):17–23.

  11. 11.

    Li YZ, Sun X, Gong T, Liu J, Zuo J, Zhang ZR. Inhalable microparticles as carriers for pulmonary delivery of thymopentin-loaded solid lipid nanoparticles. Pharm Res. 2010;27:1977–86.

  12. 12.

    Audhya T, Goldstein G. Thymopentin (TP-5) potency in vivo is enhanced by slow infusion. Int J Pept Protein Res. 1983;22:568–72.

  13. 13.

    Yin Y, Chen D, Qiao M, Lu Z, Hu H. Preparation and evaluation of lectin-conjugated PLGA nanoparticles for oral delivery of thymopentin. J Control Release. 2006;116:337–45.

  14. 14.

    Yin Y, Chen D, Qiao M, Wei X, Hu H. Lectin-conjugated PLGA nanoparticles loaded with thymopentin: ex vivo bioadhesion and in vivo biodistribution. J Control Release. 2007;123:27–38.

  15. 15.

    Wu C, Zhang M, Zhang Z, Wan KW, Ahmed W, Phoenix DA, et al. Thymopentin nanoparticles engineered with high loading efficiency, improved pharmacokinetic properties, and enhanced immunostimulating effect using soybean phospholipid and PHBHHx polymer. Mol Pharm. 2014;11:3371–7.

  16. 16.

    Wei G, Jin L, Xu L, Liu Y, Lu W. Preparation, characterization and in vivo pharmacodynamic evaluation of thymopentin loaded poly(lactide acid)/poly(lactide-co-glycolide acid) implants. Int J Pharm. 2010;398:123–9.

  17. 17.

    Zhang Y, Wu X, Han Y, Mo F, Duan Y, Li S. Novel thymopentin release systems prepared from bioresorbable PLA-PEG-PLA hydrogels. nt J Pharm. 2010;386:15–22.

  18. 18.

    Lin S, Cai B, Quan G, Peng T, Yao G, Zhu C, et al. Novel strategy for immunomodulation: dissolving microneedle array encapsulating thymopentin fabricated by modified two-step molding technology. Eur J Pharm Biopharm. 2018;122:104–12.

  19. 19.

    Zhong Y, Chen L, Zhang Y, Li W, Sun X, Gong T, et al. Vesicular phospholipid gels using low concentrations of phospholipids for the sustained release of thymopentin: pharmacokinetics and pharmacodynamics. Pharmazie. 2013;68:811–5.

  20. 20.

    Zhang T, Peng Q, San FY, Luo JW, Wang MX, Wu WQ, et al. A high-efficiency, low-toxicity, phospholipids-based phase separation gel for long-term delivery of peptides. Biomaterials. 2015;45:1–9.

  21. 21.

    Simmons BA, Taylor CE, Landis FA, John VT, McPherson GL, Schwartz DK, et al. Microstructure determination of AOT+ phenol organogels utilizing small-angle X-ray scattering and atomic force microscopy. J Am Chem Soc. 2001;123:2414–21.

  22. 22.

    Ki MH, Lim JL, Ko JY, Park SH, Kim JE, Cho HJ, et al. A new injectable liquid crystal system for one month delivery of leuprolide. J Control Release. 2014;185:62–70.

  23. 23.

    Sauerbrey A, McPherson JP, Zhao SC, Banerjee D, Bertino JR. Expression of a novel double-mutant dihydrofolate reductase-cytidine deaminase fusion gene confers resistance to both methotrexate and cytosine arabinoside. Hum Gene Ther. 1999;10:2495–504.

  24. 24.

    Ravar F, Saadat E, Gholami M, Dehghankelishadi P, Mahdavi M, Azami S, et al. Hyaluronic acid-coated liposomes for targeted delivery of paclitaxel, in-vitro characterization and in-vivo evaluation. J Control Release. 2016;229:10–22.

  25. 25.

    Peng Q, Zhang ZR, Gong T, Chen GQ, Sun X. A rapid-acting, long-acting insulin formulation based on a phospholipid complex loaded PHBHHx nanoparticles. Biomaterials. 2012;33:1583–8.

  26. 26.

    Wang M, Shan F, Zou Y, Sun X, Zhang ZR, Fu Y, et al. Pharmacokinetic and pharmacodynamic study of a phospholipid-based phase separation gel for once a month administration of octreotide. J J Control Release. 2016;230:45–56.

  27. 27.

    Gurfinkel J, Aserin A, Garti N. Interactions of surfactants in nonionic/anionic reverse hexagonal mesophases and solubilization of α-chymotrypsinogen A. Colloids Surf A. 2011;392:322–8.

  28. 28.

    Tischio JP, Patrick JE, Weintraub HS, Chasin M, Goldstein G. Short in vitro half-life of thymopoietin32--36 pentapeptide in human plasma. Int J Pept Protein Res. 1979;14:479–84.

  29. 29.

    Zhu MX, Wan WL, Li HS, Wang J, Chen GA, Ke XY. Thymopentin enhances the generation of T-cell lineage derived from human embryonic stem cells in vitro. Exp Cell Res. 2015;331:387–98.

  30. 30.

    Wang J, Lu WL, Liang GW, Wu KC, Zhang CG, Zhang X, et al. Pharmacokinetics, toxicity of nasal cilia and immunomodulating effects in Sprague-Dawley rats following intranasal delivery of thymopentin with or without absorption enhancers. Peptides. 2006;27:826–35.

  31. 31.

    Tang X, Yin C, Zhang F, Fu Y, Chen W, Chen Y, et al. Measurement of subgroups of peripheral blood T lymphocytes in patients with severe acute respiratory syndrome and its clinical significance. Chin Med J. 2003;116:827–30.

  32. 32.

    Treitinger A, Spada C, Verdi JC, Miranda AF, Oliveira OV, Silveira MV, et al. Decreased antioxidant defence in individuals infected by the human immunodeficiency virus. Eur J Clin Invest. 2000;30:454–9.

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This work was supported by grants from the National Natural Science Foundation of China (81690261 and 81673359).

Author contribution

T.G., T.Z. and Z.-r.Z. conceived the ideas and designed the experiments; T.Z., X.Q., X.C. and W.-h.L. conducted the experiments; T.Z. and T.G. interpreted the data and wrote the manuscript. All authors agree to be accountable for all aspects of the work.

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Correspondence to Tao Gong.

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The authors declare no competing interests.

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  • thymopentin
  • phospholipid-based phase separation gel (PPSG)
  • phase transition
  • sustained drug release
  • pharmacokinetics
  • immunoregulatory effect
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