Smart microgels as drug delivery vehicles for the natural drug aescin: uptake, release and interactions

Abstract

In the present study, we show how acrylamide-based microgels can be employed for the uptake and release of the drug β-aescin, a widely used natural product with a variety of pharmacological effects. We show how aescin is incorporated into the microgel particles. It has an important influence on the structure of the microgels, by reducing their natural network-density gradient in the swollen state. Moreover, temperature-dependent measurements reveal how the incorporation of aescin stabilizes the microgel particles, while the volume phase transition temperature (VPTT) is almost constant, which is very important for the intended drug release. Finally, it is shown that upon increase of the temperature above the VPTT the particles are able to release aescin from their network, encouraging the use of this particular drug delivery system for hypothermia treatments.

Importance of pH in Synthesis of pH-Responsive Cationic Nano- and Microgels

“…Their increasing popularity can be attributed to their responsiveness towards external stimuli such as temperature or pH, which is achieved by polymerizing certain monomers such as acrylamides and weak acids or bases [ 9 , 10 , 11 , 12 , 13 , 14 ] and due to their tunability in size [ 15 ] and architecture [ 16 , 17 , 18 , 19 ]. A rapid change in size upon changing these stimuli enables a vast variety of possible applications in the fields of catalysis, sensing, drug targeting, surface-functionalization or bio-conjugation [ 7 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 ]. The latter is often mentioned together with cationic nano- and microgels that are far less studied than their anionic counterparts [ 25 ].…”

Temperature Controlled Loading and Release of the Anti-Inflammatory Drug Cannabidiol by Smart Microgels

“…Regarding the use of microgels as drug-delivery vehicles, many different studies have been performed with varying drugs, ranging from lysozyme [ 24 ] over the more hydrophilic drugs dopamine, naproxen, desipramine, dibucaine, acetaminophen [ 25 ], and -aescin [ 26 ] to the hydrophobic doxorubicin (DOX) [ 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. Just from these representative examples, it can be stated that the structure of microgels, which often exhibit a rather hydrophobic, cross-linker rich core region and a rather hydrophilic corona [ 34 ], enables these particles to act as carriers for a variety of hydrophilic and hydrophobic drugs.…”

“…In this context, a good loading is achieved, and the drug is released slowly from the carrier system without the active ingredient being adversely affected. Compared to Kataokas approach, microgels could potentially be advantageous for such an application, as their ability to react to external stimuli such as temperature [ 26 ] or pH [ 36 ] can be easily utilized to realize a targeted release of active ingredients with the highest possible precision. One of the most remarkable examples in this context is probably the novel drug cannabidiol (CBD) [ 37 ], which is often applied after being dissolved in olive oil.…”

Acrylamide precipitation polymerization in a continuous flow reactor: an in situ FTIR study reveals kinetics

“…of Chemistry, Physical and Biophysical Chemistry, Bielefeld University, Universitätsstr. 25, 33615Bielefeld, Germany which is of great interest in various fields, like controlled catalysis [11,12], biocatalysis [13,14], sensor design [15][16][17][18], drug delivery [19,20], microreactors [21], smart membrane fabrication [22,23], surface coating [24,25] and microfluidics [26][27][28]. The properties of microgels can be influenced by copolymerization [29] or by architecture [30][31][32][33].…”