Temperature-Sensitive Poly(vinyl alcohol)/Poly(methacrylate-co-N-isopropyl acrylamide) Microgels for Doxorubicin Delivery

Abstract

Microgels based on poly(vinyl alcohol), PVA, grafted with methacrylate side chains, MA, incorporating N-isopropylacrylamide, NiPAAm, monomer, were prepared by water-in-water emulsion polymerization method. These systems exhibit a spherical shape and a volume-phase transition, that is, shrinking, below physiological temperature. The behavior of these microgels were studied with respect to their average size and size distribution, swelling, and release properties. It was observed that the stirring speed is a key parameter for controlling the amount of incorporated NiPAAm, the particle size and the sharpness of the volume-phase transition. The volumephase transition temperature, VPPT, of the microgels was evaluated around 38 and 34°C for microgels with a NiPAAm/methacrylate molar ratio of 0.8 and 2.4, respectively. Water uptake increased with the amount of NiPAAm monomer present in the polymer network. In vitro biocompatibility of microgels was assessed with respect to NIH3T3 mouse fibroblasts. O-Succinoylated microgels were loaded with doxorubicin by exploiting the favorable electrostatic interaction between negatively charged microgel surface and positively charged doxorubicin. The drug release was influenced by the microgels surface/volume ratio. At physiological temperatures, above the VPTT exhibited by these systems, the release was enhanced by the specific area increase. This study provides the background for the design of an injectable device suitable for the controlled delivery of doxorubicin based on the volume-phase transition of microgels.

Hydrogels based on chemically modified poly(vinyl alcohol) (PVA-GMA) and PVA-GMA/chondroitin sulfate: Preparation and characterization

“…PVA and several polysaccharides have been modified with acrylates and methacrylates by different ways [17][18][19][20]. The addition of unsaturations to polymers allows the reticulation of modified polymers without the addition of cross-linking agents [21][22][23][24][25][26]. The reaction may be carried out through the radical initiator pathway or by UV-light [27].…”

Quantitative X-ray microscopic analysis of individual thermoresponsive microgel particles in aqueous solution

“…51,52 The effective amount of NIPAM incorporated in the network was 22% (w/w) and the average diameter of the particles was 1.8 mm according to scanning electron microscopy (dry state), DLS and confocal scanning laser microscopy (CLSM) in solution. The incorporation of NIPAM induces a thermoresponsive deswelling of the PVA-based microgel network above a VPTT of about 33 C to achieve a new type of switchable microgels for drug transport.…”

“…The incorporation of NIPAM induces a thermoresponsive deswelling of the PVA-based microgel network above a VPTT of about 33 C to achieve a new type of switchable microgels for drug transport. 51 Data on the effect of NIPAM content on the swelling degree of the particles are provided in the ESI (Table S1 †). An average chemical structure of the PMN-II network and a SEM micrograph of exemplary microgel particles in dry state are depicted in Fig.…”

Amin Grupları ile Fonksiyonelleştirilmiş Poli(vinil alkol) Aşı Kopolimerinin İlaç Salım Sistemlerinde Kullanımının İncelenmesi

“…İlaç salımının LCST'nin altında (25°C) fizyolojik sıcaklığa göre (LCST'nin üstünde, 37°C) daha yavaş olduğu bulunmuştur. Bu durumun, ilaç salımının ortam sıcaklığına, şişmeye ve yüklü ilaç ile mikrojel arasındaki etkileşime bağlı olduğu belirtilmiştir [12].…”