Stimuli-responsive polymers and their applications in drug delivery

Abstract

Interest in stimuli-responsive polymers is steadily gaining increasing momentum especially in the fields of controlled and self-regulated drug delivery. Delivery systems based on these polymers are developed to closely resemble the normal physiological process of the diseased state ensuring optimum drug release according to the physiological need. Also termed 'environmental-sensitive' or 'smart', these polymers experience rapid changes in their microstructure from a hydrophilic to a hydrophobic state triggered by small changes in the environment. The changes are reversible; therefore, the polymer is capable of returning to its initial state as soon as the trigger is removed. Stimuli may occur internally (e.g. a change in pH in certain organs or diseased states, a change in temperature or the presence of specific enzymes or antigens). External stimuli include magnetic or electric fields, light, ultrasound, etc. This review will delve into the various internally and externally stimuli-responsive polymers and the drug delivery systems that exploit them.

Application of 3d Printing in Electro Induced Drug Delivery Based on Wound Temperature

“…This drug delivery system is applied by means of biomimetic actuators 10 . The magnetic responsive drug delivery system is based on magnet targeted to wound site that pulls the drug towards the magnet field and it can applied to the cancer treatment 11 .…”

“…The research on smart drug delivery system for the chronic wounds showed it by using stimulated responsive polymers 11 . The method can be stimulated by various environments alike; temperature, electric, magnetic fields.…”

Interactions in aromatic probe molecule loaded poly(N-isopropylacrylamide) hydrogels and implications for drug delivery

“…Since temperature is a highly important parameter in the mammalian body, temperaturesensitive hydrogels have become the most investigated smart polymers [2][3]. The majority of thermosensitive hydrogels investigated in the past decades are synthetic polymers based on poly(N-isopropylacrylamide) (PNIPA) [2][3][4].…”

“…The majority of thermosensitive hydrogels investigated in the past decades are synthetic polymers based on poly(N-isopropylacrylamide) (PNIPA) [2][3][4]. PNIPA hydrogels exhibit a non-linear volume phase transition (VPT) at a lower critical solution temperature (LCST) around 34 °C, which is close to the natural temperature of the human body [3,5]. On being triggered by stepwise temperature changes PNIPA can exhibit a pulsatile drug release profile [3,[6][7].…”

“…PNIPA hydrogels exhibit a non-linear volume phase transition (VPT) at a lower critical solution temperature (LCST) around 34 °C, which is close to the natural temperature of the human body [3,5]. On being triggered by stepwise temperature changes PNIPA can exhibit a pulsatile drug release profile [3,[6][7].…”