To remove uremic octapeptide from the blood stream of uremic patients, various modified polyacylamide crosslinked absorbents were prepared. Adsorption experiments showed these absorbents have significant differences in adsorption capacity to the target peptide. In this paper, two-dimension proton nuclear magnetic resonance (2D 1H NMR) spectroscopy was used to investigate the interaction mechanism between the peptide and the adsorbents. Because of the insolubility of the absorbent, some soluble linear polymers with the same functional groups as the absorbents were employed as the model adsorbents in 2D 1H NMR. The preferred binding site for the peptide and polymers was identified to be at the C-terminal carboxyl group of the octapeptide via chemical shift perturbation effects. In this study, we found that hydrogen bonding, electrostatic, and hydrophobic interactions all play a role in the interaction force but had different contributions. Especially, the great chemical shift changes of the aromatic amino acid residues (Trp) during the interaction between butyl-modified polyacrylamide and octapeptide suggested the hydrophobic interaction, incorporated with the electrostatic force, played an important role in the binding reaction in aqueous solutions. This information not only rationally explained the results of the adsorption experiments, but also identified the effective binding site and mechanism, and shall provide a structural basis for designing better affinity-type adsorbents for the target peptide.

A class of polyesters have been synthesized by the ring-opening copolymerization of DL-lactide (DLLA) and RS-benzyloxyethyl-b-malolactonate (MABE) using different monomer feeding doses. The compositions and structures of poly(DL-lactide-co-RS-benzyloxyethyl-b-malolactonate) (poly(DLLA-co-MABE)) were determined by 1H and 13C NMR measurements. GPC measurement showed that the molecular weight of the copolymers decreased as the MABE content increases. After catalytic hydrogenation of the benzyl ether functions, the desired copolymers with pendent hydroxyl arms, poly(DL-lactide-co-RS-hydroxyethyl-b-malolactonate) (poly(DLLA-co-MAHE)), were recovered. Thermal properties of poly(DLLA-co-MABE) and poly(DLLA-co-MAHE) copolymers were examined by differential scanning calorimetry (DSC) measurement. Single glass transition temperature appeared in the DSC spectra, which confirmed that the copolymers were true copolymers and not blends. The hydrophilicity of poly(DLLA-co-MAHE) copolymer was tunable, which increased with the increase in MAHE content. Furthermore, the hydrolytic degradation of poly(DLLA-co-MAHE) material was investigated and the results showed that faster degradation was observed in the copolymer film containing more MAHE content.

In this paper, a series of adsorbents with different amino acid ligands for endotoxin removal were prepared and endotoxin adsorption capacities (EAC) in aqueous solution were studied using an affinity column. The results showed that the property and structure of amino acid ligands have great influence on EAC. As the increasing of isoelectric point and polarity of amino acids ligands, EACs of the adsorbents increased. In addition, computer simulation method was employed to a further investigation on the interaction between endotoxins and ligands. Based on the results, some adsorbents were applied to remove endotoxin from endotoxemia rabbit’s serum. Similar adsorption results were observed and the removal efficiency of adsorbents with Arg, Ser ligands is up to 78%.

Disclosed are a hepatic targeted drug delivery system and a process for preparing the same. Also disclosed is a method for treating liver cancer.