Investigation of Mildronat$^{\mathrm{\circledR}}$ diffusion in human eye sclera

Background and Objectives: Diseases of retina and optic nerve are the major causes of vision loss. The use of new drugs in the treatment of these diseases can reduce the decline of visual function due to the involvement of additional mechanisms of cell metabolism compensation. Thus, investigation of the drug diffusion in sclera is an important task at estimation of dose necessary for achievement of enough drug concentration in internal eye tissues. Since Mildronat$^{\mathrm{\circledR}}$ facilitates restoration of ATP transport and can improve metabolic processes, purpose of this study is to investigate the permeability of sclera for Mildronat$^{\mathrm{\circledR}}$. Material and Methods: The method of determination of diffusion coefficient was based on registration of time dependence changing of scattering characteristics of sclera due to partial replacement of interstitial fluid by Mildronat$^{\mathrm{\circledR}}$ what produced sclera reflectance decreasing. The reflectance measurements were carried out on ten samples of human sclera with fiber-optic spectrometer in the spectral range 450–1000 nm during 5–10 min. Processing and analysis of the experimental data were performed in the framework of free diffusion model on the base of inverse Monte Carlo simulation. Results: The measured value of Mildronat$^{\mathrm{\circledR}}$ diffusion coefficient in human sclera is $(1.31 \pm 0.66) \times 10^{-6}$ cm$^2$/sec. Conclusion: The value of Mildronat$^{\text{\circledR}}$ diffusion coefficient in the human sclera in vitro is important for determining dose of administered drug sufficient to achieve the internal parts of eye, time required for effective drug impact, etc., which is of great importance for the treatment of partial optic nerve atrophy and several other ophthalmic diseases.