Purchase this article with an account.
F. M. Penha, E. B. Rodrigues, E. P. F. Costa, E. Dib, M. Maia, A. A. Lima Filho, Sr., M. E. Farah; Biochemical Analysis of Indocyanine Green Ph, Anions, Osmolarity, Preciptation and Decomposition Products: In Relation to Solvents, Dye Concentration and Light Exposure. Invest. Ophthalmol. Vis. Sci. 2010;51(13):3598.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To investigate pH, ions, osmolarity, precipitation and decomposition products of indocyanine green (ICG) related to solvents, dye concentration and light exposure.
ICG was first diluted in water, than diluted with 5% glucose (GL) or balanced salt solution (BSS) to achieve: 2.5, 1, 0.25 and 0.1 mg/mL.Osmolarity, pH and precipitation were analyzed immediately and after 24h. Precipitation analyzes was done weighting the precipitates after PVDF 0.45 µm millipore filtration and scanning electron microscope (SEM) for morphology documentation. Anions and iodates analyzes was done by capillary zone electrophoresis.The same dilution method was assessed for decomposition products (DP) with high-performance liquid chromatography (HPLC). This analyzis was done immediately and 24 hours with daylight exposure to evaluate light induced decomposition of ICG.
BSS promotes iso-osmotic ICG solutions 208 mOsm (147 - 266), compared to GL 177 mOsm (130 - 229). BSS solutions had more physiologic pH 7,2 (7,08 - 7,33), than GL 6,55 (6,17 - 7,56). ICG precipitated more when diluted with GL 4,23 mg (3,3 - 5,5), BSS has 3,81 mg (1,3 - 12,2). SEM showed numerous and more spiculated precipitates when diluted in BSS. Anions analyzes showed that infracyanine has no iodate and other ICG’s have average 4,6% of iodate derivates (range from 4,2 to 5,4). From HPLC analyzes, five decomposition products were founded. The number of DP was greater in more diluted solutions, when BSS was used as solvent, and after light exposition.
Solvents are important issue for ICG preparation. BSS showed greater biochemical profile as ICG solvent, with more physiologic pH and osmolarity over GL. However, BSS promotes more precipitates and ICG decomposition products. Iodine is implicated in retina toxicity, infracyanine has no iodine, so in theory is safer than other ICG’s. Other in vitro and in vivo studies should be performed in order to evaluate the importance of this findings.
This PDF is available to Subscribers Only