Poly(N‐isopropylacrylamide)‐Based Polymers: Recent Overview for the Development of Temperature‐Responsive Drug Delivery and Biomedical Applications

Abstract

Temperature is a widely incorporated stimulus in pharmaceutical applications because of its efficiency as a therapeutic medium; thus, substantial evidence on temperature‐responsive polymer applications is reported. Poly(N‐isopropylacrylamide) (PNIPAAm) is a well‐established, temperature‐responsive polymer that exhibits a low critical solution temperature (LCST) at ≈ 32°C, which is close to physiological temperature. Hence, they are widely used in various pharmaceutical applications, such as drug delivery with nanocarriers and thermogels. Varying the LCST for different applications can be achieved by copolymerization with other hydrophobic or hydrophilic molecules, making it a favorable smart polymer. PNIPAAm is reported to enhance drug delivery by incorporation with nanocarriers and to facilitate prolonged drug delivery, thereby avoiding the burst release of drugs in temperature‐responsive hydrogels. The application of PNIPAAm is not limited to drug delivery, and it is also applied in biomedical applications such as chromatography systems and cell culture applications, where its incorporation in cell culture media enhances cell production. The unique and versatile properties of PNIPAAm render it a promising smart polymer for various functional applications. Hence, this review focuses on the diverse applications of PNIPAAm.This article is protected by copyright. All rights reserved

Hyaluronic Acid-Conjugated Thermoresponsive Polymer-Based Bioformulation Enhanced Wound Healing and Gut Barrier Repair of a TNBS-Induced Colitis Injury Ex Vivo Model in a Dynamic Perfusion Device

“…Furthermore, the ability to alter the physicochemical characteristics of PNIPAM through copolymerization provides a great scope for modifying the base polymer as per the required application. 19,20 In this work, we have developed a sprayable thermoresponsive (PNIPAM-based) formulation that upon administration inside the colon can instantly form a physical coating onto the colon wall to timely cover the wound openings, prevent bacterial translocation, provide optimum drug concentration at the diseased site, and promote mucosal self-repair and regeneration. To achieve such outcomes using our therapeutic formulation, we have incorporated hyaluronic acid into the PNIPAM chains.…”

“…Poly­( N -isopropylacrylamide) (PNIPAM) has been one of the most studied thermoresponsive polymers due to the ease of polymer synthesis and its physiological lower critical solution temperature (∼32 °C) in water. Furthermore, the ability to alter the physicochemical characteristics of PNIPAM through copolymerization provides a great scope for modifying the base polymer as per the required application. , …”

Preparation and characterization of temperature/pH/CO2-triple-responsive homopolymers and their substituent determined response

“…4,5 For example, temperature-responsive polymers, which have received more attention from researchers, show a phase transition at a specific temperature, resulting in a sudden change in the dissolved state. 6–13 The best known temperature-responsive polymer is poly( N -isopropylacrylamide) (PNIPAM), which has a lower critical solution temperature (LCST) and has become a major material in the versatile and dynamic area of polymer science. 8,9 Polymers with ionizable groups such as the amine group, the carboxyl group, etc ., whose degree of ionization varies with pH, often exhibit pH-response.…”

“…6–13 The best known temperature-responsive polymer is poly( N -isopropylacrylamide) (PNIPAM), which has a lower critical solution temperature (LCST) and has become a major material in the versatile and dynamic area of polymer science. 8,9 Polymers with ionizable groups such as the amine group, the carboxyl group, etc ., whose degree of ionization varies with pH, often exhibit pH-response. 14–18 There are many pH changes in biological systems; especially when the tissue is diseased, the pH will be mutated, so in the field of biological medicine, pH-responsive polymers as intelligent targeted drug carriers have broad application prospects.…”