Upper critical solution temperature polymeric drug carriers

Stimuli-responsive polymers are widely used as drug carriers in therapeutic applications. Upper critical solution temperature (UCST) polymeric carriers undergo a phase transition from hydrophobic to hydrophilic under the stimuli of temperature, near-infrared light, microwave, etc., thereby achieving a much more complete drug release. UCST polymeric carriers have recently emerged great potentials for controlled drug release, such as UCST polymeric micelles and hydrogels for cancer treatments and UCST polymeric surfaces for wound treatments, etc.. In this review, we mainly focus on UCST polymeric drug carriers based on different forms in recent five years. Various UCST polymers are first summarized based on their different structures. Drug-loaded UCST polymeric micelles with different stimuli, including with or without photothermal agents, pH-responsive and self-monitoring polymeric micelles, and representative drug-loaded UCST polymeric surfaces, including UCST polymeric coatings and mesoporous silica with UCST polymeric “gate”, are introduced. Finally, drug-loaded UCST polymeric hydrogels are also discussed. This review aims to draw attention to the advantages of UCST polymeric drug carriers and promote their clinical practice.