Development and pharmacokinetics of galactosylated poly-L-glutamic acid as a biodegradable carrier for liver-specific drug delivery

Purpose. A biodegradable carrier for the liver-specific delivery of drugs was developed using poly-l-glutamic acid (PLGA) modified with galactose (galactosylated PLGA or Gal-PLGA), and its feasibility was investigated in mice. Methods. In-111-PLGA and In-111-Gal-PLGAs were injected in mice and their distribution and biodegradation properties were studied. Results. After intravenous injection, In-111-PLGA was rapidly eliminated from the plasma and recovered mainly in the kidneys and urine. Approximately 15% of the dose was recovered in the liver, predominantly in the nonparenchymal cells. In-111-Gal-PLGAs were taken up by the liver parenchymal cells. Derivatives having 16 or more galactose residues were taken up by the liver to a higher extent ( > 60% of the dose). The hepatic clearance of In-111-Gal-PLGAs correlated with their number of galactose residues. In-111-Gal(18)-PLGA was degraded into low-molecular weight products in the liver. Conclusions. The advantageous in vivo properties of Gal-PLGA as a liver-specific biodegradable carrier of drugs were demonstrated in mice.