Smart Drug Delivery Systems

Abstract

In previous chapters, we identified the nature of the pharmacokinetic profile for a series of controlled-release systems. The zero-order release represented a simple, idealized, gradual release response, which allowed for a predicted dosage to be delivered over a predictable time regime. As we shifted our discussion to encapsulated and targeted systems, it became apparent that the zero-order release would be less relevant since the design strategy for these systems is to prevent interaction between the drug and physiological environment until the drug reaches the tissue target. Upon reaching the target, the system is either consumed or degraded in order to release the drug dosage form into the cellular environment. An important question that arises at this point in the discussion is What facilitates the release of drug into the cellular environment?In Chap. 5, we identified the targeting groups on the surface of self-emulsifying systems that contribute to their adhesion and consumption by cellular species through receptor-mediated endocytosis or macropinocytosis. In our previous discussion, we assumed that the vesicle or micelle was being either destabilized or degraded within the cell lysosomes to release the drug into the intracellular environment. This approach has some functional limitations since it consists of several factors that are dependent on cellular function and response. The analogy would be when you fly on a plane and arrive at a destination, one surefire way to know that you have arrived, aside from the landing, is that the doors open and people leave. Can you imagine an airline where the plane would have to erode completely, or worse crash, before you were permitted to leave? For this precise reason, it is often

Ultrasound-Triggered Amoxicillin Release from Chitosan/Ethylene Glycol Diglycidyl Ether/Amoxicillin Hydrogels Having a Covalently Bonded Network

“…Such DDS systems in combination with external stimulation have become popular because of their superior drug release efficiency and more precise control of their characteristics. 20,21 Among these stimulants, US retains the advantages of deep penetration, noninvasiveness, and nontoxicity 22 to the human body, as well as simple operation and low cost 21,23 compared to other DDSs. The efficient penetration from the outside to the inside of the body is a major feature not found in other external stimuli and the release of the drug toward the outside of the drug matrix can be controlled by changing the US intensity without loading the specimen.…”

“…Recently, to increase the efficiency of sustained drug release, smart DDSs that could be controlled sustainably by external stimuli have been reported, and the drug matrix responded to external stimuli such as light, thermal, , pH, , and ultrasound (US) , to enhance the drug efficiency of DDSs. Such DDS systems in combination with external stimulation have become popular because of their superior drug release efficiency and more precise control of their characteristics. , Among these stimulants, US retains the advantages of deep penetration, noninvasiveness, and nontoxicity to the human body, as well as simple operation and low cost , compared to other DDSs. The efficient penetration from the outside to the inside of the body is a major feature not found in other external stimuli and the release of the drug toward the outside of the drug matrix can be controlled by changing the US intensity without loading the specimen. , In fact, US waves can be transmitted through water and induce oscillatory motion of the surrounding fluid, acoustic streaming, cavitation, and thermal effect. , US treatment has been proven to be beneficial in a variety of cases, including treatment of diabetes, stroke, cancer, infections, skin dehydration, and bone fractures .…”

Layer-by-Layer Fabrication of Hydrogel Microsystems for Controlled Drug Delivery From Untethered Microrobots

“…In the last few decades, the medical approach toward the administration of drugs has been characterized by radical improvements. Together with the continuous development of new active principles, research has also been focused on the improvement of delivery techniques for already existing formulations ( Alvarez-Lorenzo and Concheiro, 2014 ; Holowka and Bhatia, 2014 ; Wang et al, 2016 ). Indeed, usage optimization is a matter of major relevance when considering the problems generally related to conventional drug administration: misuse (either self-conscious or related to difficult posology), presence of negative side effects and induced drug resistance for cancer ( Vasan et al, 2019) and microorganisms ( Sekyere and Asante, 2018 ).…”

Effect of Different Physical Cross-Linkers on Drug Release from Hydrogel Layers Coated on Magnetically Steerable 3D-Printed Microdevices

“…Starting from these premises, it is evident that targeting drug delivery is a matter of major importance in modern pharmacology [6,7]. In the last few decades, a wealth of smart delivery approaches has been proposed at the laboratory scale: liposomes [8,9], polymeric thin layers [10], DNA nanostructures [11], dendrimers [12], micelles [13] and biocompatible nanoparticles [14][15][16].…”