Novel pH- and Temperature-Responsive Blend Hydrogel Microspheres of Sodium Alginate and PNIPAAm-g-GG for Controlled Release of Isoniazid

Abstract

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 pH1.2 and pH7.4 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.

Sodium Alginate–locust Bean Gum Ipn Hydrogel Beads for the Controlled Delivery of Nimesulide-Anti-Inflammatory Drug

“…A similar observation was noted by Krishna Rao et al, [33] from the cefedroxil drug release studies through interpenetrating network microgels of chitosan/acrylamide grafted PVA. …”

Chitosan nanoparticles as carrier systems for the plant growth hormone gibberellic acid

“…It has been found previously that a higher temperature alters the viscosity and hydrophilicity of polymers such as ALG and CS, which can be used to improve control of the release of an active agent [26,50]. This was not observed here for the carrier systems containing GA 3 .…”

The design of pH-sensitive chitosan-based formulations for gastrointestinal delivery

“…In this section, we will review the two types of cross-linking preparations according to the development of cross-linkers. Many bifunctional small molecules such as glutaraldehyde, urea formaldehyde and pyromellitic dianhydride have been successfully applied to cross-link to chitosan-based polymers for intestinal drug delivery, as shown in Table 1 [41][42][43][44][45]. These molecules could take advantage of the available -NH 2 and -OH chemical handles on the chitosan backbone to form linkage chemistries, including Schiff base and amide formation.…”