Intratumoral Injection Administration of Irinotecan-Loaded Microspheres: In Vitro and In Vivo Evaluation


To reduce the toxic and side effects of intravenous chemotherapeutic drugs on the tumor-patients, the aims of this study were to design and study intratumor-administrated irinotecan-loaded PLGA microspheres (CPT-11-PLGA-MS) in vitro and in vivo according to the structure characteristics of CPT-11. PLGA microspheres containing irinotecan were prepared by emulsion solvent evaporation method and evaluated in terms of their morphology, particle size analysis, in vitro drug release, drug retention and leakage studies in vivo, and pharmacodynamics studies. The CPT-11-PLGA-MS were spherical with mean size of 9.29 ± 0.02 μm, and average encapsulation efficiency were measured of 77.97 ± 1.26% along with the average drug loading of 7.08 ± 0.11%. DSC results indicated that the drug existed in the phase of uncrystallization in the microspheres. The formulation of CPT-11-PLGA-MS could prolong the in vitro drug release to 16 days following Weibull equation. In CPT-11-PLGA-MS after intratumor injection administration was significantly improved. The results demonstrated that the slow-sustained release of CPT-11-PLGA-MS in tumor tissue after intratumor injection of microspheres can reduce the drug leakage to the circulation system, maintain the drug retention, and improve the therapeutic effect, which could become a promising drug delivery system for CPT-11 and could maintain the most effective concentration at the target site to maximum limit.

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The authors would like to express thanks to the School of Pharmaceutical Science, Shandong University for providing the required infrastructure to carry out the study.

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Correspondence to Mingjin Dou or Guihua Huang.

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The work described has not been submitted elsewhere for publication in whole or in part, and all the authors listed have approved the manuscript that is enclosed. The authors declare that they have no conflict of interest. The authors alone are responsible for the content and writing of this article.

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Zhu, S., Dou, M. & Huang, G. Intratumoral Injection Administration of Irinotecan-Loaded Microspheres: In Vitro and In Vivo Evaluation. AAPS PharmSciTech 19, 3829–3838 (2018).

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  • irinotecan
  • intratumor-administration
  • microspheres
  • 7-ethyl-10-hydroxycamptothecin
  • lactone ring structure