Stimuli-induced Pulsatile or Triggered Release Delivery Systems for Bioactive Compounds

Abstract

As is frequently found in the living body, many vital functions are regulated by pulsed or triggered release of bioactive substances at a specific site and time. Thus it is important to develop new drug delivery devices to achieve pulsed delivery of a certain amount of drugs in order to mimic the function of the living systems to minimize the undesired side effects. The pulsed or triggered delivery systems are designed to alter their rate of drug delivery in response to stimuli such as changes in a specific molecule, a magnetic or electric field, temperature, light or mechanical forces. Such systems are suitable for the release of therapeutics that benefit from non-constant plasma concentrations. In this article, several types of drug delivery systems which cause the pulsed or triggered release of bioactive compounds due to certain external stimuli, mostly focuses on thermally-, electrically-and magnetically-induced release are described in detail. The recent patents on various delivery systems which release the active compounds only with the external stimuli are described in detail.

Smart micro/nanoparticles in stimulus-responsive drug/gene delivery systems

“…The introduction of polyelectrolytes containing large numbers of ionizable groups confers responsiveness to an electrical stimulus through shrinking or swelling of the polymers. 144,145 For instance, Ying et al developed electro-responsive hydrogel NPs for targeted delivery of an antiepileptic drug (Phenytoin sodium, Fig. 8).…”

Stimuli-Responsive Polymers and Their Applications in Nanomedicine

“…Electrical and electrochemical stimuli are widely used in research and applications, due to their advantages of precise control via the magnitude of the current, the duration of an electrical pulse or the interval between pulses [21,22]. Typical electrically responsive polymers are conducting polymers, as for example polythiophene (PT) or sulphonated-polystyrene (PSS), which can show swelling, shrinking or bending in response to an external field [23,24].…”

Smart Polymers in Drug Delivery

“…The equipment employed to control the applied electric field allows precise regulation of the current, the time interval between electric pulses, and the duration of electrical pulses (Anal 2007). The polymers are typically polyelectrolytes consisting of large numbers of ionizable groups in the polymer chain (Qiu and Park 2001;Anal 2007).…”

“…The equipment employed to control the applied electric field allows precise regulation of the current, the time interval between electric pulses, and the duration of electrical pulses (Anal 2007). The polymers are typically polyelectrolytes consisting of large numbers of ionizable groups in the polymer chain (Qiu and Park 2001;Anal 2007). The mechanism involved in the release of drug moieties from such systems is similar to that of pH-sensitive polymers (Shiga 1998;Kim et al 1999;Kulkarni and Biswanath 2007;Ramanathan and Block 2001).…”