Effects of silibinin hemisuccinate on the intraocular pressure in normotensive rabbits

Objective: To evaluate the effects of silibinin hemisuccinate on the normal intraocular pressure (IOP) in rabbits. Methods: This study took place in the Department of Pharmacology and Toxicology, College of Pharmacy, University of Baghdad, during the period from January to June 2005. Twenty-five New Zealand white rabbits weighing 1.5-2.5 kg were used in this study. The effects of corneal instillation of various concentrations of silibinin hemisuccinate (0.5%, 0.75% and 1%) dissolved in arachis oil, on the normal intraocular pressure in rabbits were evaluated using indentation tonometry, in addition to the possible modulation of normal IOP-recovery time after intravenous infusion of a 20% sodium chloride solution. Results: The results showed that within 30 minutes of application, silibinin in various concentrations significantly reduced IOP in comparison to baseline values (p<0.05), with greater reduction being achieved with 0.75%. The effect of IOP reduction lasts 2–3 hours and is proportionate to the concentration used. Moreover, a remarkable delay in IOP recovery was observed after instillation of silibinin compared with the vehicle-treated (arachis oil) animals, indicating interference with aqueous humor formation. Conclusion: The results obtained in this study provide experimental evidence for the effectiveness of silibinin in the reduction of IOP and possible modulation of its regulatory mechanisms.

https://pubmed.ncbi.nlm.nih.gov/17768468/