Electroactive polyacrylamide/chitosan/polypyrrole hydrogel for captopril release controlled by electricity

Abstract

The demand for the development of new therapies and devices for controlled drug release has been continuously increasing, especially those based on materials sensitives to external stimuli, such as electricity. Therefore, in this work, acrylamide was polymerized in the presence of chitosan (CS), using N,N 0methylenebisacrylamide as cross-linking, followed by immersion in pyrrole aqueous solution and chemical polymerization to obtain an electroactive hydrogel of polyacrylamide/CS/polypyrrole (PA/CS/PPy) (67.5/7.5/25% wt.); this electroactive hydrogel was later used in drug delivery controlled by electricity studies. The synthesized PA/CS/PPy hydrogel was characterized by scanning electron microscopy, FTIR spectroscopy, and thermogravimetric analysis. It was observed that the hydrogel presented pores in the range of 50-200 μm with CS and PPy well incorporated to the cross-linked PA. The hydrogel swelling percentage (S) was determined at different pHs. It was observed that S was independent of pH, with S = 700% and a swelling kinetics described by the Fickian diffusion mechanism at alkaline pH. PA/CS/PPy hydrogel was used to absorb captopril (a drug for hypertension control), and its kinetics release at different applied potentials and pH was studied. Release kinetics were described by the Korsmeyer-Peppas model, while release mechanism was a Case-II transport without current at alkaline pH; under electrical stimuli, the mechanism presented an anomalous transport with ON-OFF profile, increasing the release rate with the applied voltage showing its electroactivity in the captopril release.

The synthesis, mechanisms, and additives for bio‐compatible polyvinyl alcohol hydrogels: A review on current advances, trends, and future outlook

“…CS is the product of alkaline deacetylation of chitin in the walls of shrimps, crabs, insect exoskeletons and some fungi. [111,112] The properties of CS, such as biocompatibility, biodegradability, non-toxicity, antioxidizing behavior, antibacterial and anticancer properties have led to its use F I G U R E 3 Illustration of the formation process of the CS-PVA hybrid hydrogel and chemical bonds between CS, Cit 3À , and PVA in hydrogel (A-D); the stress-strain curves (E), tensile strength and breaking elongation (F), W ext and Young's modulus (G) of the CS-PVA hybrid hydrogel; 3D-printed lifelike hydrogel whale, octopus, and butterfly (H). Reproduced with permission from ref.…”

“…CS is the product of alkaline deacetylation of chitin in the walls of shrimps, crabs, insect exoskeletons and some fungi. [ 111,112 ] The properties of CS, such as biocompatibility, biodegradability, non‐toxicity, antioxidizing behavior, antibacterial and anticancer properties have led to its use in a wide range of applications in food, medicine and tissue engineering. [ 113–115 ] CS is able to enhance the mechanical properties of PVA hydrogels due to its ability to form thin films without the use of any additives, as well as its renewable, biodegradable and antibacterial properties.…”

Preparation of poly(acrylic acid)/linseed mucilage/chitosan hydrogel for ketorolac release

“…Therefore, they can be used for biomedical applications, especially due to their biocompatibility and soft texture; they are used in drug delivery devices. 3,4 Usually, hydrogels for drug delivery or controlled drug release consist of composites of interpenetrated polymeric networks, allowing the manipulation of their chemical composition and mechanical properties, that is, the combination of synthetic polymeric hydrogels with natural biopolymers, such as chitosan. After cellulose, chitosan is the second most abundant biopolymer on the surface of the Earth.…”

“…Charged hydrogels, usually change their swelling behavior when exposed to external stimuli such as pH or electricity. Therefore, they can be used for biomedical applications, especially due to their biocompatibility and soft texture; they are used in drug delivery devices 3,4 …”

Development of novel reversible thermometer from N‐isopropylacrylamide and dicyanodihydrofuran hydrazone probe

“…Color change is a reflection of structural shape changes of the polymer geometry induced by the temperature in the aqueous media. [24][25][26][27][28][29][30][31][32] Yoo et al embedded five different polydiacetylene polymers into polyvinyl alcohol by a mixing-drying method. [33] The resulting polymer strip sensor can gradually change from blue to red after passing purple as if smoothly moving across the colored spectrum in response to a temperature range from 50 to above 130 C. Of the five polymers, the aldehyde-based polymers showed the most thermal responsiveness but formed the least stable films due to their lack of hydrogen bonding capability.…”