Tannic acid-based sustained-release system for protein drugs.

In recent years, protein drug development has gained momentum, and simple and facile controlled-release systems without loss of activity are required. Herein, we developed a sustained-release system for protein drugs by exploiting the "astringency" mechanism, namely insoluble precipitate formation by interacting with tannic acid. Tannic acid formed insoluble precipitates with various protein drugs, such as nisin, insulin, lysozyme, ovalbumin, hyaluronidase, and human immunoglobulin G, through hydrophobic interactions and hydrogen bonds.

Polyrotaxane-Based Supramolecular Material for Improvement of Pharmaceutical Properties of Protein Drugs.

Pharmaceutical excipients, such as surfactants, amino acids, and polymers, have often been used to improve the physicochemical properties of protein drugs. However, the effects of these additives are limited because of factors such as their weak interactions with protein drugs. In the present study, we evaluated the application of a supramolecular polymer, aminated polyrotaxane (NH-PRX), which can strongly interact with protein drugs via its dynamic and transformable properties, as a new pharmaceutical excipient for these agents.

Supramolecular polymer-based transformable material for reversible PEGylation of protein drugs.

We herein developed a transformable mixing-type material for reversible PEGylation of protein drugs using a supramolecular backbone polymer, that is, polyrotaxane possessing both amino groups and PEG chains (PEG-NH-PRX). We expected that PEG-NH-PRX provides amino groups to interact with protein drugs on demand because the mobility of amino groups in PEG-NH-PRX was high. In fact, PEG-NH-PRX formed complexes with protein drugs efficiently compared to PEGylated amino-dextran (PEG-NH-DEX), a control material fabricated with a macromolecular backbone polymer.