Toxicity and in vivo release profile of sirolimus from implants into the vitreous of rabbits’ eyes
- 28 Downloads
To assess the in vivo release profile and the retinal toxicity of a poly (lactic-co-glycolic acid) (PLGA) sustained-release sirolimus (SRL) intravitreal implant in normal rabbit eyes.
PLGA intravitreal implants containing or not SRL were prepared, and the viability of ARPE-19 and hES-RPE human retinal cell lines was examined after 24 and 72 h of exposure to implants. New Zealand rabbits were randomly divided into two groups that received intravitreal implants containing or not SRL. At each time point (1–8 weeks), four animals from the SRL group were euthanized, the vitreous was collected, and drug concentration was calculated. Clinical evaluation of the eyes was performed weekly for 8 weeks after administration. Electroretinography (ERG) was recorded in other eight animals, four for each group, at baseline and at 24 h, 1, 4, 6, and 8 weeks after the injection. ERG was carried out using scotopic and photopic protocols. The safety of the implants was assessed using statistical analysis of the ERG parameters (a and b waves, a and b implicit time, B/A ratio, oscillatory potential, and Naka–Rushton analysis) comparing the functional integrity of the retina between the PLGA and SRL-PLGA groups. After the last electrophysiological assessment, the rabbits were euthanized and retinal histopathology was realized.
After 24 and 72 h of incubation with PLGA or SRL-PLGA implants, ARPE-19 and hES-RPE cells showed viability over 70%. The maximum concentration of SRL (199.8 ng/mL) released from the device occurred within 4 weeks. No toxic effects of the implants or increase in the intraocular pressure was observed through clinical evaluation of the eye. ERG responses showed no significant difference between the eyes that received PLGA or SRL-PLGA implants at baseline and throughout the 8 weeks of follow-up. No remarkable difference in retinal histopathology was detected in rabbit eyes treated with PLGA or SRL-PLGA implants.
Intravitreal PLGA or SRL-PLGA implants caused no significant reduction in cell viability and showed no evident toxic effect on the function or structure of the retina of the animals. SRL was released from PLGA implant after application in the vitreous of rabbits during 8 weeks.
KeywordsCell viability Electroretinography Intravitreal drug delivery Sirolimus Biodegradable implant Toxicity
The authors thank CNPq/MCT (Brazil), Fapemig (Brazil), and CAPES/MEC (Brazil) for the financial support.
Compliance with ethical standards
Conflicts of interest
The authors declare that they have no conflict of interest.
The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.
Informed consent was not applicable.
Statement of human rights
This article does not contain any studies with human participants performed by any of the authors.
Statement on the welfare of animals
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted.
- 13.Dejneka NS, Kuroki AM, Fosnot J, Tang W, Tolentino MJ, Bennett J (2004) Systemic rapamycin inhibits retinal and choroidal neovascularization in mice. Mol Vis 10:964–972. http://www.molvis.org/molvis/v10/a115/
- 29.Nguyen QD, Ibrahim MA, Watters A et al (2013) Ocular tolerability and efficacy of intravitreal and subconjunctival injections of sirolimus in patients with non-infectious uveitis: primary 6-month results of the SAVE Study. J Ophthalmic Inflamm Infect 3:32. https://doi.org/10.1186/1869-5760-3-32 CrossRefPubMedPubMedCentralGoogle Scholar
- 42.ISO 10993-5. (2009) Biological evaluation of medical devices—Part 5: tests for in vitro cytotoxicityGoogle Scholar
- 45.Li G, Cao L, Zhou Z et al (2015) Rapamycin loaded magnetic Fe3O4/carboxymethylchitosan nanoparticles as tumor-targeted drug delivery system: synthesis and in vitro characterization. Colloids Surf B Biointerfaces 128:379–388. https://doi.org/10.1016/j.colsurfb.2015.02.035 CrossRefPubMedGoogle Scholar
- 48.Fernandes-Cunha GM, Gouvea DR, de Oliveira Fulgêncio G et al (2015) Development of a method to quantify clindamycin in vitreous humor of rabbits’ eyes by UPLC-MS/MS: application to a comparative pharmacokinetic study and in vivo ocular biocompatibility evaluation. J Pharm Biomed Anal 102:346–352. https://doi.org/10.1016/j.jpba.2014.08.023 CrossRefPubMedGoogle Scholar
- 49.Fialho SL, Souza PAF, de Oliveira Fulgêncio G et al (2013) In vivo release and retinal safety of intravitreal implants of thalidomide in rabbit eyes and antiangiogenic effect on the chorioallantoic membrane. J Drug Target 21:837–845. https://doi.org/10.3109/1061186X.2013.829074 CrossRefPubMedGoogle Scholar
- 54.Peters T, Kim S-W, Castro V et al (2017) Evaluation of polyesteramide (PEA) and polyester (PLGA) microspheres as intravitreal drug delivery systems in albino rats. Biomaterials. https://doi.org/10.1016/j.biomaterials.2017.02.006 CrossRefPubMedGoogle Scholar