Cyclosporine-Loaded Microspheres for Treatment of Uveitis: In Vitro Characterization and In Vivo Pharmacokinetic Study

The 3H-CyS-poly(lactic-co-glycolic acid) -MS suspension was injected into the vitreous body of healthy rabbits, and the concentration of cyclosporine in various ocular tissues and blood at predetermined intervals was measured by a scintillation counting technique and the pharmacokinetic parameters were calculated

Yuan He

2006

Scholarcy highlights

  • The 3H-CyS-poly(lactic-co-glycolic acid)-MS suspension was injected into the vitreous body of healthy rabbits, and the concentration of cyclosporine in various ocular tissues and blood at predetermined intervals was measured by a scintillation counting technique and the pharmacokinetic parameters were calculated
  • Intravitreous injection of CyS solution has been performed in the rat model with experimental autoimmune uveitis by Nussenblatt et al.,10who found that intravitreous CyS therapy protects eyes from EAU without producing significant circulating CyS levels, which is consistent with our results
  • Many sustained-release systems have been proposed for CyS intravitreous delivery, including biodegradable implants and nonbiodegradable implants.11121314151617All implants described previously had a common disadvantage, in that these implants had to be placed by surgery which made the administration risky and inconvenient
  • The microsphere system which could pass through 20- to 23-gauge needles and be readily injected has been investigated for ophthalmologic application.1819As shown in our studies, the maximum concentration of CyS in most ocular tissues in the microsphere group was approximately 35 days, and the concentration of CyS in most ocular tissues was relatively steady over the whole period of 65 days compared with solution group
  • Japanese White rabbits weighing between 2 and 3 kg were acclimated for at least 1 week under standardized temperature, humidity, and light conditions before experiment
  • PLGA microspheres showed the potential for intraocular sustained-release of CyS, because the mean residence time was increased about 10 times compared with the CyS solution, and a therapeutic drug level was maintained for 65 days, especially in disorder-related tissues such as the choroid-retina, vitreous body, and iris-ciliary body, which are the primary target of uveitis
  • Data show the correlation between the in vitro cumulative CyS released and the AUCt/AUC65 values in various ocular tissues and blood after injection of 3H-CyS-poly(lactic-co-glycolic acid)-MS into the vitreous body of rabbits

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