The Delivery of Platinum Drugs from Thermosensitive Hydrogels Containing Different Ratios of Chitosan

Abstract

New thermosensitive hydrogels of poly(N-isopropylacrylamide) (PNIPAAm) with chitosan (CPN) were prepared and evaluated for use in the delivery of the platinum drugs, cisplatin and carboplatin. The effects of polymers containing different ratios of chitosan on the physicochemical and drug release characteristics were examined. The sol-gel transition temperature of the hydrogels was determined by differential scanning calorimetry (DSC) and viscometry. Discrepancies in the transition temperature among the various polymer systems were more pronounced when determined by viscosity compared by DSC, with the CPN showing a higher transition temperature than PNIPAAm. The cross-sectional structure and surface topography of the hydrogels were examined by scanning electronic microscopy (SEM) and atomic force microscopy (AFM), respectively. The incorporation of chitosan further increased the entanglement of the hydrogel network. An increase in the chitosan ratio in the polymers (CPN-H) also increased the cross-linking structure. A smoother surface of hydrogel matrices was observed for CPN compared with PNIPAAm. All hydrogels tested significantly reduced drug release compared with an aqueous solution. The release rate of platinum drugs from PNIPAAm was retarded at the late stage. CPN matrices could continuously deliver platinum drugs during the experiment. The rate of release from CPN-H was generally slower than that from hydrogels and had a lower chitosan ratio (CPN-L), presumably due to the more-tortuous pathways in the hydrogels. Thermosensitive hydrogels like those prepared in

Controlled Release Characteristics of Aqueous PEO‐PPO‐PEO Micelles With Added Malachite Green, Erythrosin, and Cisplatin Determined by UV–Visible Spectroscopy

“…. The cumulative release results in general compares well to previous cisplatin encapsulated drug delivery systems (Cheng et al, ; Czarnobaj & Lukasiak, ; Fang, Chen, Leu, & J‐W, ; Guven et al, ; Reardon et al, ). Guven et al () reported less than 25% total released cisplatin from their Pluronic ® F108‐wrapped, W‐CDDP@US‐tubes after 200 h. Cheng et al () reported less than 10% total cisplatin release from their Fe‐cisplatin loaded nanoparticles, Pt‐PHNPs, at pH 7.4, 6, and 5 after 70 h. Reardon et al () reported less than 20% cumulative release of cisplatin after 10 h from their core‐shell poly(lactic‐ co ‐glycolic acid) (PLGA) nanoparticles.…”

Preparation and evaluation of thermo-reversible copolymer hydrogels containing chitosan and hyaluronic acid as injectable cell carriers

“…Our present report aims at the synthesis of CPN and HA-CPN copolymers based on the combination of PNIPAM-COOH, chitosan and HA in the presence of water-soluble EDC/NHS. CPN is a comb-like copolymer with PNIPAM side chain extending from the chitosan backbone [22,23]. The double grafted HA-CPN was synthesized by grafting CPN onto the HA molecules [24,25].…”

“…Previously, we reported the synthesis of chitosan-g-poly(Nisopropylacrylamide) (CPN), a thermo-responsive comb-like polymer with chitosan as the backbone and pendant PNIPAM groups, by grafting PNIPAM-COOH with a single carboxyl end group onto chitosan through amide bond linkages [22,23]. In vitro cell culture experiments demonstrated usefulness of this hydrogel as an injectable cell carrier [22].…”

Thermally and magnetically dual‐responsive mesoporous silica nanospheres: preparation, characterization, and properties for the controlled release of sophoridine

“…PNIPAAm has the property of having a soluble (hydrophilic)–insoluble (hydrophobic) transition at a lower critical solution temperature (LCST) of about 32°C in water; it exhibits a coil (soluble) state when the temperature is below the LCST and a collapsed (insoluble) state when the temperature is above the LCST . Moreover, PNIPAAm is also among the smart polymers most commonly used to modify nanoparticles in drug‐delivery systems . The thermally responsive behavior of PNIPAAm can be used to design a smart nanoshell on the exterior surface of MSNs; this may be the ideal way to take up and control the release of drugs based on temperature changes.…”