Stimuli sensitive polymers and self regulated drug delivery systems: A very partial review

Abstract

Since the early days of the Journal of Controlled Release, there has been considerable interest in materials that can release drug on an “on-demand” basis. So called “stimuli-responsive” and “intelligent” systems have been designed to deliver drug at various times or at various sites in the body, according to a stimulus that is either endogenous or externally applied. In the past three decades, research along these lines has taken numerous directions, and each new generation of investigators has discovered new physicochemical principles and chemical schemes by which the release properties of materials can be altered. No single review could possibly do justice to all of these approaches. In this article, some general observations are made, and a partial history of the field is presented. Both open loop and closed loop systems are discussed. Special emphasis is placed on stimuli-responsive hydrogels, and on systems that can respond repeatedly. It is argued that the most success at present and in the foreseeable future is with systems in which biosensing and actuation (i.e. drug delivery) are separated, with a human and/or cybernetic operator linking the two.

Preparation of thermo and pH-responsive polymer@Au/Fe3O4 core/shell nanoparticles as a carrier for delivery of anticancer agent

“…Polymeric nanoparticles (NPs) have shown promising applications as nano-carriers of drugs and contrast agents due to their unique properties (Sahoo et al 2013;Siegel 2014). Among the polymeric NPs, the nanomaterials with stimuli-responsive structure and function have attracted impressive interest among researchers in respect of delivery of various drugs, especially anticancer agents (Bawa et al 2009;Salehi and Hamishehkar 2014;Sundaresan et al 2014).…”

Controlled Drug Release Systems: Mechanisms and Kinetics

“…Depending upon the polymer, the system can either shrink or swell upon a change in any of these environmental factors. For most of these polymers, which are also called responsive or "smart", the structural changes are reversible and repeatable upon additional changes in the external environment [Siegel, 2014]. One of the most famous and studied responsive polymers that finds applications in drug delivery has been poly(N-isopropyl acrylamide) due to its low critical solution temperature in water at 32°C, close to body temperature.…”

Dispositivo implantável de EUDRAGIR/PCL-T/ Diclofenaco de sódio: caracterização mecânica, liberação do fármaco e atividade anti-inflamatóriain vivo

“…Many of these systems are in early stages of development, and a number of questions are yet to be answered. [1][2][3][4][5][6][7] The non-steroidal anti-inflammatory drugs (NSAIDs) are among the most commonly consumed medications in the world. They are used to decrease pain and inflammation caused by various diseases, such as in the treatment of arthritis.…”