Thermo- and pH-responsive polymers in drug delivery.

Thermosensitive sol-gel reversible hydrogels.

A concentrated fish soup could be gelled in the winter and re-solled upon heating. In contrast, some synthetic copolymers exhibit an inverse sol–gel transition with spontaneous physical gelation upon heating instead of cooling. If the transition in water takes place below the body temperature and the chemicals are biocompatible and biodegradable, such gelling behavior makes the associated physical gels injectable biomaterials with unique applications in drug delivery and tissue engineering etc. Various therapeutic agents or cells can be entrapped in situ and form a depot merely by a syringe injection of their aqueous solutions at target sites with minimal invasiveness and pain. This tutorial review summarizes and comments on this soft matter, especially thermogelling poly(ethylene glycol)–(biodegradable polyester) block copolymers. The main types of injectable hydrogels are also briefly introduced, including both physical gels and chemical gels.

Injectable hydrogels as unique biomedical materials

The formulation and delivery of biopharmaceutical drugs, such as monoclonal antibodies and recombinant proteins, poses substantial challenges owing to their large size and susceptibility to degradation. In this Review we highlight recent advances in formulation and delivery strategies — such as the use of microsphere-based controlled-release technologies, protein modification methods that make use of polyethylene glycol and other polymers, and genetic manipulation of biopharmaceutical drugs — and discuss their advantages and limitations. We also highlight current and emerging delivery routes that provide an alternative to injection, including transdermal, oral and pulmonary delivery routes. In addition, the potential of targeted and intracellular protein delivery is discussed.

Overcoming the challenges in administering biopharmaceuticals: formulation and delivery strategies

In situ-forming hydrogels--review of temperature-sensitive systems.

Biodegradable block copolymers for delivery of proteins and water-insoluble drugs

18. Biodegradable block copolymers for delivery of proteins and water-insoluble drugs: reflections and commentary a decade later: Original research article: Biodegradable block copolymers for delivery and proteins water-insoluble drugs, 2001.

Min Hyo Seo

Papers

Biodegradable block copolymers for delivery of proteins and water-insoluble drugs

18. Biodegradable block copolymers for delivery of proteins and water-insoluble drugs: reflections and commentary a decade later: Original research article: Biodegradable block copolymers for delivery and proteins water-insoluble drugs, 2001.