Balance of drug residence and diffusion in lacrimal fluid determine ocular bioavailability in in situ gels incorporating tranilast nanoparticles

Misa Minami, Hiroko Otake, Yosuke Nakazawa, Norio Okamoto, Naoki Yamamoto, Hiroshi Sasaki, Noriaki Nagai

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)


We previously designed ophthalmic formulations (nTRA) containing tranilast nanoparti-cles (Tra-NPs) with high uptake into ocular tissues. In this study, we used in situ gel (ISG) bases comprising combinations of pluronic F127 (F127) and methylcellulose (MC/F127), pluronic F68 (F68/F127), and Carbopol (Car/F127), and we developed in situ gels incorporating Tra-NPs (Tra-NP-incorporated ISNGs) such as nTRA-F127, nTRA-MC/F127, nTRA-F68/F127, and nTRA-Car/F127. Moreover, we demonstrated the therapeutic effect on conjunctival inflammation using lipopolysaccharide-induced rats. Each Tra-NP-incorporated ISNG was prepared by the bead mill method, the particle size was 40–190 nm, and the tranilast release and diffusion from formulation were nTRA > nTRA-F127 > nTRA-F68/F127 > nTRA-Car/F127 > nTRA-MC/F127. In the Tra-NP-in-corporated ISNGs, the tranilast residence time in the lacrimal fluid, cornea, and conjunctiva was prolonged, although the Cmax was attenuated in comparison with nTRA. On the other hand, no significant difference in conjunctival inflammation between non-and nTRA-F127-instilled rats was found; however, the nTRA-F68/F127, nTRA-Car/F127, and nTRA-MC/F127 (combination-ISG) attenuated the vessel leakage, nitric oxide, and tumor necrosis factor-α expression. In particular, nTRA-F68/F127 was significant in preventing the conjunctival inflammation. In conclusion, we found that the combination-ISG base prolonged the residence time of Tra-NPs; however, Tra-NP release from the formulation was attenuated, and the Tmax was delayed longer than that in nTRA. The balance of drug residence and diffusion in lacrimal fluid may be important in providing high ocular bioavailability in formulations containing solid nanoparticles.

Original languageEnglish
Article number1425
Issue number9
Publication statusPublished - 2021 Sept


  • In situ gelling system
  • Nanoparticles
  • Ophthalmic delivery
  • Pluronic F-127
  • Tranilast

ASJC Scopus subject areas

  • Pharmaceutical Science


Dive into the research topics of 'Balance of drug residence and diffusion in lacrimal fluid determine ocular bioavailability in in situ gels incorporating tranilast nanoparticles'. Together they form a unique fingerprint.

Cite this