scholarly journals Temperature and pH Responsive Microfibers for Controllable and Variable Ibuprofen Delivery

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Toan Tran ◽  
Mariana Hernandez ◽  
Dhruvil Patel ◽  
Ji Wu
Keyword(s):  
Drug Delivery ◽  
Solution Temperature ◽  
Pharmaceutical Sciences ◽  
Electrospinning Technique ◽  
Critical Solution Temperature ◽  
Practical Applications ◽  
Responsive Polymers ◽  
Ph Values ◽  
Higher Temperature ◽  
Diffusion Rates

Electrospun microfibers (MFs) composed of pH and temperature responsive polymers can be used for controllable and variable delivery of ibuprofen. First, electrospinning technique was employed to prepare poly(ε-caprolactone) (PCL) and poly(N-isopropylacrylamide-co-methacrylic acid) (pNIPAM-co-MAA) MFs containing ibuprofen. It was found that drug release rates from PCL MFs cannot be significantly varied by either temperature (22–40°C) or pH values (1.7–7.4). In contrast, the ibuprofen (IP) diffusion rates from pNIPAM-co-MAA MFs were very sensitive to changes in both temperature and pH. The IP release from pNIPAM-co-MAA MFs was highly linear and controllable when the temperature was above the lower critical solution temperature (LCST) of pNIPAM-co-MAA (33°C) and the pH was lower than thepKaof carboxylic acids (pH 2). At room temperature, however, the release rate was dramatically increased by nearly ten times compared to that at higher temperature and lower pH. Such a unique and controllable drug delivery system could be naturally envisioned to find many practical applications in biomedical and pharmaceutical sciences such as programmable transdermal drug delivery.

scholarly journals Thermo- and Photoresponsive Behaviors of Dual-Stimuli-Responsive Organogels Consisting of Homopolymers of Coumarin-Containing Methacrylate

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 329
Author(s):  
Seidai Okada ◽  
Eriko Sato
Keyword(s):  
Functional Group ◽  
Solution Temperature ◽  
Stimuli Responsive ◽  
Critical Solution Temperature ◽  
Equilibrium Degree ◽  
Stimuli Responsive Polymers ◽  
Responsive Polymers ◽  
Dual Functional ◽  
Wide Range ◽  
Increasing Temperature

Coumarin-containing vinyl homopolymers, such as poly(7-methacryloyloxycoumarin) (P1a) and poly(7-(2′-methacryloyloxyethoxy)coumarin) (P1b), show a lower critical solution temperature (LCST) in chloroform, which can be controlled by the [2 + 2] photochemical cycloaddition of the coumarin moiety, and they are recognized as monofunctional dual-stimuli-responsive polymers. A single functional group of monofunctional dual-stimuli-responsive polymers responds to dual stimuli and can be introduced more uniformly and densely than those of dual-functional dual-stimuli-responsive polymers. In this study, considering a wide range of applications, organogels consisting of P1a and P1b, i.e., P1a-gel and P1b-gel, respectively, were synthesized, and their thermo- and photoresponsive behaviors in chloroform were investigated in detail. P1a-gel and P1b-gel in a swollen state (transparent) exhibited phase separation (turbid) through a temperature jump and reached a shrunken state (transparent), i.e., an equilibrium state, over time. Moreover, the equilibrium degree of swelling decreased non-linearly with increasing temperature. Furthermore, different thermoresponsive sites were photopatterned on the organogel through the photodimerization of the coumarin unit. The organogels consisting of homopolymers of coumarin-containing methacrylate exhibited unique thermo- and photoresponsivities and behaved as monofunctional dual-stimuli-responsive organogels.

scholarly journals Synthesis and characterization of PIL/pNIPAAm hybrid hydrogels

2016 ◽  
Vol 2 (1) ◽  
pp. 1-4
Author(s):  
Sylvia Pfensig ◽  
Daniela Arbeiter ◽  
Klaus-Peter Schmitz ◽  
Niels Grabow ◽  
Thomas Eickner ◽  
...  
Keyword(s):  
Mechanical Characterization ◽  
Heating Temperature ◽  
Controlled Drug Release ◽  
Solution Temperature ◽  
Scanning Calorimetry ◽  
Critical Solution Temperature ◽  
Temperature Range ◽  
Hybrid Hydrogels ◽  
Higher Temperature

AbstractIn this study, varying amounts of NIPAAm and an ionic liquid (IL), namely 1-vinyl-3-isopropylimidazolium bromide ([ViPrIm]+[Br]−), have been used to synthesize hybrid hydrogels by radical emulsion polymerization. Amounts of 70/30%, 50/50%, 30/70%, 15/85% and 5/95% (wt/wt) of PIL/pNIPAAm were used to produce hybrid hydrogels as well as the parental hydrogels. The adhesive strength was investigated and evaluated for mechanical characterization. Thermal properties of resulting hydrogels have been investigated using differential scanning calorimetry (DSC) in a default heating temperature range (heating rate 10 K min−1). The presence of poly ionic liquids (PIL) in the polymer matrix leads to a moved LCST (lower critical solution temperature) to a higher temperature range for certain hybrid hydrogels PIL/pNIPAAm. While pNIPAAm exhibits an LCST at 33.9 ± 0.3°C, PIL/pNIPAAm 5/95% and PIL/pNIPAAm 15/85% were found to have LCSTs at 37.6 ± 0.9°C and 52 ± 2°C, respectively. This could be used for controlled drug release that goes along with increasing body temperature in response to an implantation caused infection.

scholarly journals Modulating the Thermoresponse of Polymer-Protein Conjugates with Hydrogels for Controlled Release

Polymers ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2772
Author(s):  
Vincent Huynh ◽  
Natalie Ifraimov ◽  
Ryan G. Wylie
Keyword(s):  
Drug Delivery ◽  
Controlled Release ◽  
Ethylene Glycol ◽  
Solution Temperature ◽  
Residence Times ◽  
Release Rates ◽  
Critical Solution Temperature ◽  
Protein Conjugates ◽  
Particle Encapsulation ◽  
Glycol Methyl Ether

Sustained release is being explored to increase plasma and tissue residence times of polymer-protein therapeutics for improved efficacy. Recently, poly(oligo(ethylene glycol) methyl ether methacrylate) (PEGMA) polymers have been established as potential PEG alternatives to further decrease immunogenicity and introduce responsive or sieving properties. We developed a drug delivery system that locally depresses the lower critical solution temperature (LCST) of PEGMA-protein conjugates within zwitterionic hydrogels for controlled release. Inside the hydrogel the conjugates partially aggregate through PEGMA-PEGMA chain interactions to limit their release rates, whereas conjugates outside of the hydrogel are completely solubilized. Release can therefore be tuned by altering hydrogel components and the PEGMA’s temperature sensitivity without the need for traditional controlled release mechanisms such as particle encapsulation or affinity interactions. Combining local LCST depression technology and degradable zwitterionic hydrogels, complete release of the conjugate was achieved over 13 days.

scholarly journals Bioengineered Scaffolds for Thermo-responsive Drug Delivery in Wound Healing

2020 ◽  
Author(s):  
Luis Castillo-Henríquez ◽  
Jose Castro-Alpízar ◽  
Mary Lopretti-Correa ◽  
José Vega-Baudrit
Keyword(s):  
Drug Delivery ◽  
Wound Healing ◽  
Chronic Wounds ◽  
Clinical Symptoms ◽  
Solution Temperature ◽  
Thermal Stimulus ◽  
The Novel ◽  
Responsive Polymers ◽  
Biodegradable Scaffolds ◽  
Manufacturing Techniques

innate and adaptive immune responses lead to wound healing by regulating a complex series of events promoting cellular cross-talk. An inflammatory response is presented with its characteristic clinical symptoms: heat, pain, redness, and swelling. Some smart thermo-responsive polymers like chitosan can be used to create biocompatible and biodegradable scaffolds with 3D architectures similar to human structures, allowing their efficient and safe use as tissue engineering and drug delivery systems in chronic wounds. Locally heated tumors above polymer lower critical solution temperature can induce its conversion into a hydrophobic form, enhancing drug release until the thermal stimulus is gone, where a lower release is due to the swelling of the material. This paper integrates the relevant reported contributions of bioengineered scaffolds for thermo-responsive drug delivery in wound healing. Therefore, we present a comprehensive review that aims to demonstrate the capacity of these systems to provide spatially and temporally controlled release strategies for one or more drugs used in wound healing. In this sense, the novel manufacturing techniques of 3D-printing and electrospinning are explored for the tuning of their physicochemical properties to adjust therapies according to the patient’s convenience, as well as reduce drug toxicity and side effects.

Upper critical solution temperature polymer-grafted hollow mesoporous silica nanoparticles for near-infrared-irradiated drug release

2019 ◽  
Vol 7 (38) ◽  
pp. 5789-5796 ◽  
Author(s):  
Wei Hu ◽  
Xiaowen Bai ◽  
Yaping Wang ◽  
Zhentao Lei ◽  
Haipeng Luo ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Near Infrared ◽  
Mesoporous Silica Nanoparticles ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Promising Strategy ◽  
Upper Critical Solution Temperature ◽  
Hollow Mesoporous Silica

A near-infrared (NIR)-responsive drug delivery system was established by grafting UCST polymers on the surfaces of hollow mesoporous silica nanoparticles (HMSNs) using the photothermal agent indocyanine green (ICG), which provided a new and promising strategy for drug delivery.

Aqueous Stability of Cross-Linked Thermal Responsive Tissue Engineering Scaffold Produced by Electrospinning Technique

2021 ◽  
Vol 897 ◽  
pp. 39-44
Author(s):  
Hsin Nam Ernest Yong ◽  
Kim Yeow Tshai ◽  
Siew Shee Lim
Keyword(s):  
Tissue Engineering ◽  
Culture Media ◽  
Total Porosity ◽  
Solution Temperature ◽  
Electrospinning Technique ◽  
Cell Culture Media ◽  
Critical Solution Temperature ◽  
Nanofibrous Scaffolds ◽  
Electrospun Nanofibres ◽  
Oligomeric Silsesquioxane

Poly (N-isopropylacrylamide) (PNIPAm) has been one of the most widely studied thermal responsive polymer in tissue engineering owing to its reversible hydrophilic-hydrophobic phase transition across its lower critical solution temperature (~32°C) that is close to human physiological temperatures. Among tissue engineering constructs, nanofibrous scaffolds offer an added advantage in mimicking the morphology of the native extracellular matrix (ECM). Electrospinning has been reported as one of the most facile method to produce PNIPAm nanofibres and neat electrospun nanofibres scaffold is known to possess poor aqueous stability, limiting its use in tissue engineering applications. In contrast, numerous studies on PNIPAm hydrogels have shown relatively good aqueous stability owing to the hydrophilic 3D crosslinked structure of the hydrogel which resist instant dissolution but rather swell to a greater or lesser extent. However, the presence of crosslinkages in PNIPAm hydrogels causes it to be hardly electrospinnable into nanofibres. In the present work, crosslinker free PNIPAm was radical polymerized to a high molecular weight of 385 kDa. To produce nanofibers, electrospinning was carried out on a dedicated %wt of PNIPAm solution containing octaglycidyl polyhedral oligomeric silsesquioxane (OpePOSS) and 2-ethyl-4-methylimidazole (EMI). Resulting PNIPAm nanofibrous network was found to strongly resemble the ECM morphology with fiber diameter of 436.35 ± 187.04 nm, pore size 1.24 ± 1.27 μm and 63.6% total porosity. Aqueous stability was studied in cell culture media over the course of 28 days. The current result shows significant improvement with a gradual mass loss up to a maximum of 35% instead of the near immediate dissolution observed in the case of electrospun neat PNIPAm scaffold without crosslinks.

Synthesis of Gold Nanoflowers Encapsulated with Poly(N-isopropylacrylamide-co-acrylic acid) Hydrogels

2015 ◽  
Vol 15 (10) ◽  
pp. 7962-7965 ◽  
Author(s):  
Saet-Byeol Bae ◽  
Sang-Wh Lee
Keyword(s):  
Drug Delivery ◽  
Particle Size ◽  
Ascorbic Acid ◽  
Oleic Acid ◽  
Polymerization Reaction ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Monomer Ratio ◽  
Carboxylate Groups ◽  
Gold Nanoflowers

In this work, hydrogel-coated gold nanoflowers (AuNFs@hydrogel) were facilely prepared. First, gold nanoflowers (AuNFs) were synthesized by reducing gold acid with ascorbic acid in the presence of chitosan biopolymers, and the chitosan-mediated AuNFs were subsequently conjugated with oleic acid with carboxylate groups. Finally, the olefin-conjugated AuNFs were encapsulated with P(NIPAM-co-AAC) hydrogels via a radical polymerization reaction with co-monomer ratio of [NIPAM:AAc = 91:9 wt%]. The encapsulated hydrogels had a lower critical solution temperature (LCST) slightly above the physiological temperature and demonstrated a thermo-sensitive variation of particle size. The hydrogel-coated AuNFs can be utilized as a promising thermo-responsive drug delivery system with a unique optical property. As-prepared samples were characterized by DLS, SEM, TEM, UV-vis and Zeta potential meter.

scholarly journals Temperature Driven Transformation in Dextran-Graft-PNIPAM/Embedded Silver Nanoparticle Hybrid System

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
V. Chumachenko ◽  
N. Kutsevol ◽  
Iu Harahuts ◽  
D. Soloviov ◽  
L. Bulavin ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Silver Nanoparticles ◽  
Conformational Transition ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Thermally Induced ◽  
X Ray ◽  
X Ray Scattering ◽  
The Comparative Study ◽  
Novel Drug

During the last decade, stimuli-responsible polymers based on poly(N-isopropylacrylamide) having conformational transition in the range of physiological temperature have been discussed as novel drug delivery nanosystems. A star-like copolymer with a dextran core and grafted poly(N-isopropylacrylamide) arms (D-g-PNIPAM) was synthesized, characterized, and used as a matrix for silver sol preparation. The comparative study of the behavior of individual D-g-PNIPAM and the nanohybrid system D-g-PNIPAM/silver nanoparticles has been done in the temperature range near the lower critical solution temperature (LCST). The methods of Dynamic Light Scattering, small angle X-ray scattering, and UV-VIS absorption spectroscopy have been used. The existence of single nanoparticles and aggregated nanoparticles located in a limited polymer macromolecular volume was established. The increase of the temperature leads to slight aggregation of the silver nanoparticles at the LCST transition. Single nanoparticles do not aggregate with the temperature increase. The thermally induced collapse of end-grafted poly(N-isopropylacrylamide) chains above the LCST do not affect significantly the size characteristics of silver nanoparticles incorporated into the polymer matrix.

Antitumor Drug Delivery Modulated by A Polymeric Micelle with an Upper Critical Solution Temperature

2015 ◽  
Vol 127 (10) ◽  
pp. 3169-3174 ◽  
Author(s):  
Weishuo Li ◽  
Liwen Huang ◽  
Xiaoying Ying ◽  
You Jian ◽  
Yuan Hong ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Polymeric Micelle ◽  
Antitumor Drug ◽  
Solution Temperature ◽  
Critical Solution Temperature ◽  
Upper Critical Solution Temperature

scholarly journals How to manipulate the upper critical solution temperature (UCST)?

2017 ◽  
Vol 8 (1) ◽  
pp. 220-232 ◽  
Author(s):  
Jukka Niskanen ◽  
Heikki Tenhu
Keyword(s):  
Aqueous Solutions ◽  
Solution Temperature ◽  
Stimuli Responsive ◽  
Critical Solution Temperature ◽  
Stimuli Responsive Polymers ◽  
Responsive Polymers ◽  
Ph Influence ◽  
Counter Ions ◽  
Upper Critical Solution Temperature

In this mini-review, we discuss multi-stimuli-responsive polymers, which exhibit upper critical solution temperature (UCST) behavior mainly in aqueous solutions, and focus on examples where counter ions, electricity, light, or pH influence the thermoresponsiveness of these polymers.

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