title: Novel pH- and temperature-responsive blend hydrogel microspheres of sodium alginate and PNIPAAm-g-GG for controlled release of isoniazid.
abstract: This paper reports the preparation and characterization of novel pH- and thermo-responsive blend hydrogel microspheres of sodium alginate (NaAlg) and poly(N-isopropylacrylamide)(PNIPAAm)-grafted-guar gum (GG) i.e., PNIPAAm-g-GG by emulsion cross-linking method using glutaraldehyde (GA) as a cross-linker. Isoniazid (INZ) was chosen as the model antituberculosis drug to achieve encapsulation up to 62%. INZ has a plasma half-life of 1.5 h, whose release was extended up to 12 h. Fourier transform infrared spectroscopy was used to confirm the grafting reaction and chemical stability of INZ during the encapsulation. Differential scanning calorimetry was used to investigate the drug's physical state, while powder X-ray diffraction confirmed the molecular level dispersion of INZ in the matrix. Scanning electron microscopy confirmed varying surface morphologies of the drug-loaded microspheres. Temperature- and pH-responsive nature of the blend hydrogel microspheres were investigated by equilibrium swelling, and in vitro release experiments were performed in pH 1.2 and pH 7.4 buffer media at 37°C as well as at 25°C. Kinetics of INZ release was analyzed by Ritger-Peppas empirical equation to compute the diffusional exponent parameter (n), whose value ranged between 0.27 and 0.58, indicating the release of INZ follows a diffusion swelling controlled release mechanism.
authors.affiliation: Department of Chemistry, Karnatak University, Dharwad, 580 003, India.
authors.forename: Praveen B
authors.initials: PB
authors.lastname: Kajjari
authors.forename: Lata S
authors.initials: LS
authors.lastname: Manjeshwar
authors.forename: Tejraj M
authors.initials: TM
authors.lastname: Aminabhavi
mesh_terms: D000178:Acrylamides / Q000737:chemistry*; D000180:Acrylic Resins; D000464:Alginates / Q000737:chemistry*; D000995:Antitubercular Agents / Q000008:administration & dosage / Q000737:chemistry; D002152:Calorimetry, Differential Scanning / Q000379:methods; D002626:Chemistry, Pharmaceutical / Q000379:methods; D003692:Delayed-Action Preparations; D004655:Emulsions / Q000737:chemistry; D005685:Galactans / Q000737:chemistry*; D020723:Glucuronic Acid / Q000737:chemistry; D005976:Glutaral / Q000737:chemistry; D006207:Half-Life; D006603:Hexuronic Acids / Q000737:chemistry; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007538:Isoniazid / Q000008:administration & dosage* / Q000737:chemistry*; D007700:Kinetics; D008351:Mannans / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008863:Microspheres; D053149:Plant Gums / Q000737:chemistry*; D011108:Polymers / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods; D013696:Temperature; D014961:X-Ray Diffraction / Q000379:methods
chemical_list: D000178:Acrylamides; D000180:Acrylic Resins; D000464:Alginates; D000995:Antitubercular Agents; D003692:Delayed-Action Preparations; D004655:Emulsions; D005685:Galactans; D006603:Hexuronic Acids; D008351:Mannans; D053149:Plant Gums; D011108:Polymers; C052970:poly-N-isopropylacrylamide; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D020723:Glucuronic Acid; C007894:guar gum; D005976:Glutaral; D007538:Isoniazid