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The burst release of drugs limited the development of the thermo-responsive hydrogels based on poly N-isopropylacrylamide (NIPAAm) for application in drug delivery systems. To overcome this problem, the drug sulfadimethoxine (SDMO) was conjugated via amide bond to the PNIPAAm hydrogel instead of loaded into the system. Therefore, SDMO was modified using maleic anhydride to get N-maleyl sulfadimethoxine (NMSDMO) and then utilized that to synthesize the sulfadimethoxineconjugated PNIPAAm hydrogel (P[NIPAAm-co-NMSDMO]). The resultant monomer was then grafted into the hydrogel network at different weight percentage through radical polymerization. The NMSDMO monomer and the P[NIPAAm-co-NMSDMO] hydrogels were fully investigated. The in vitro drug released displayed sustained release in pH 5 and 7.4 for 24 h. Hydrolysis of the amide bond causes the release rate and total amount of drug to be greatest at pH 5, as compared to pH 7.4. As a result, the P[NIPAAm-co-NMSDMO] hydrogel was an effective sustained drug delivery system.

Water‐soluble phthalocyanine has been considered as a potential photosensitizer for photodynamic therapy (PDT) applications. To achieve the best efficiency of phthalocyanine in PDT, amphiphilic zinc phthalocyanine was purposely designed and synthesized by conjugation with β‐cyclodextrin. Herein, we synthesized two novel zinc phthalocyanine derivatives connected to β‐cyclodextrin moieties through covalent Schiff base linkage (TFP‐ZnPc/AβCD). In this procedure, aldehyde substituted phthalocyanine and amino‐appended β‐cyclodextrins with different length amino side chains were used. The compounds were characterized using FT‐IR, 1H NMR, MALDI‐TOF, and UV‐vis. The newly designed photosensitizers did not self‐assemble in water and generated significant singlet oxygen via 1,3‐DPBF (1,3‐diphenylisobenzofuran) bleaching. Simultaneously, longer amino side chains increase 1O2 production efficiency. The PDT activity of the new TFP‐ZnPc/AβCD complexes was then examined on human breast cancer (MDA‐MB‐231) and fibroblast cells. In vitro results show that PDT is more effective against cancer cells than normal cells. The new TFP‐ZnPc/AβCD could be an effective PDT drug.

New thermoresponsive poly(N-isopropyl acrylamide-co-phthalocyanine) magnetic nanocomposites were prepared by in situ dispersion polymerization. 4-Nitrophthalic acid and CoCl2 were employed to synthesize tetranitrophthalocyanine and then it was converted to tetraaminophthalocyanine by sodium sulfide. The cobalt tetra(N-carbonylacrylic)aminophthalocyanine monomer was obtained by reaction of tetraaminophthalocyanine with maleic anhydrid. N-isopropylacrylamide as the main monomers, N,N′-methylenebisacrylamide as the cross-linker, poly(N-vinylpyrrolidone) as the steric stabilizer, potassium persulfate as the initiator, and new Fe-phthalocyanine oligomer/Fe3O4 nanohybrid particles (FePc/Fe3O4) as nanoparticles were used. The magnetite nanocomposites were characterized by Fourier-transform infrared spectrum, X-ray diffraction spectroscopy, scanning electron microscopy, thermogravimetric analysis, vibrating sample magnetometer, and differential scanning calorimetry. The results showed that the lower critical solution temperatures of the hydrogel nanocomposits were influenced by the content of FePc/Fe3O4 hybrid nanoparticles. The lower critical solution temperatures of the magnetic hydrogel nanocomposites F3 and F4 were at about 34 and 40 °C. The results show that the increase of FePc/Fe3O4 nanoparticle content caused the LCSTs of the hydrogels to increase. FePc/Fe3O4 nanoparticles were prepared from 4,4′-isopropyliden-bis-dioxydiphthalonitrile and FeCl3·6H2O via the solvothermal route. The sizes of nanoparticles were determined by scanning electron microscopy. They are spherical in shape and the average size of them is between 30 and 70 nm.