Figure 3.

Pharmacokinetic distribution of N-retinylamides, the main metabolites of Ret-NH₂, in the liver (a) and eye (b) after oral administration of Ret-NH₂ and PEG-GFL-NH-Ret. The formulated conjugate, PEG-GFL-NH-Ret or Ret-NH₂ (1 mg equivalent of Ret-NH₂/mouse), was orally gavaged into dark-adapted 4-week-old C57BL wild-type female mice. Mice then were sacrificed at predetermined time points (4, 12, 24, 48, 72, 96, 120 h) after such treatment. N-Retinylamides were extracted from the eyes and liver and quantitatively determined by HPLC. Error bars indicate SD of the means (n = 6).