Ocular distribution of sodium pentobarbital after injection of lethal and anesthetic doses and after transfer via corneal grafting.

The distribution of sodium pentobarbital in the eye after lethal and anesthetic doses and the possibility of the drug's transfer via corneal grafting were studied in rabbits. The drug was found in all the ocular tissues and humours following the intravenous injection of a single lethal (60 mg/kg) or anesthetic (30 mg/kg) dose, and it was still present 24 hours after the anesthetic injection. In both instances the largest quantity was found in the cornea. After grafting of corneal tissue containing pentobarbital the drug dispersed into the recipients' corneas and other ocular tissues. In-vitro studies showed that 250 micrograms of the drug per millilitre of incubation medium reduced the rate of growth of the corneal fibroblasts to 50%, and 300 micrograms/mL reduced their protein synthesis to 66%. Calculations showed that these concentrations could be reached in the cornea or the aqueous humour in vivo following either the lethal or the anesthetic injection of the drug.