Controlled release of theophylline through semi-interpenetrating network microspheres of chitosan-(dextran-g-acrylamide).

Semi-interpenetrating network microspheres of chitosan-(dextran-g-acrylamide) were prepared by emulsion-crosslinking method using glutaraldehyde (GA) as a crosslinking agent. Graft copolymerization of dextran with acrylamide (Dx-g-AAm) was carried out by aqueous free-radical polymerization using ceric ammonium nitrate (CAN) as initiator. The grafting efficiency was found to be 92%. Theophylline (TH), antiasthmatic drug, was successfully encapsulated into semi-INP microspheres by varying the ratio of Dx-g-AAm and amount of GA. The laser light scattering technique shows that the particles size increased with increasing amount of graft copolymer and decrease with increasing amount of GA. The % encapsulation efficiency was found to vary between 50 and 78. MPs were characterized by FTIR spectroscopy and differential scanning calorimetry (DSC) techniques to confirm the graft copolymer, formation of semi-IPN structure of MPs and molecular distribution of the drug molecules in the polymer matrix. In vitro release studies of TH from these matrices have been investigated at Ph 1.2 and 7.4 media and the slow release were extended up to 18 h at 37 degrees C. The release rates were fitted to an empirical equation to estimate the diffusion exponent n, which indicated that the release from the MPs follows non-Fickian type.

Semi-interpenetrating network of acrylamide-grafted-sodium alginate microspheres for controlled release of diclofenac sodium, preparation and characterization.

The semi-interpenetrating networks (semi-IPNs) of acrylamide grafted sodium alginate (AAm-g-NaAlg) microspheres (MPs) were prepared by emulsion-crosslinking method using glutaraldehyde (GA) as a crosslinking agent. The grafting of acrylamide onto sodium alginate was prepared by free-radical graft polymerization using ceric ammonium nitrate (CAN) as initiator at three acrylamide concentrations with monomer to polymer ratio of 1:1, 2:1 and 3:1, respectively. The grafting efficiency was found to be 91%. The produced MPs are almost spherical in nature with smooth surfaces. Diclofenac sodium (DS), an anti-inflammatory drug was successfully encapsulated into the MPs. The encapsulation efficiency was found to vary between 83% and 95%. The MPs were characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) spectroscopy. The diffusion coefficient (D) was dependent upon the amount of crosslinking agent (GA) and amount of grafting ratio in the matrix. The rate of release was found to be dependent on the amount of GA, AAm:NaAlg grafting ratio and % drug loading in the MPs. The release data have been fitted to an empirical equation to investigate the diffusional exponent (n), which indicated that the release mechanism from MPs follows the super Case II transport.

Controlled release of diclofenac sodium through acrylamide grafted hydroxyethyl cellulose and sodium alginate.

To reinforce the hydroxyethyl cellulose for using it in biomedical and pharmaceutical applications as a drug delivery systems, the grafting of acrylamide onto hydroxyethyl cellulose (AAm-g-HEC) was achieved by Ce(IV) induced free radical polymerization. The AAm-g-HEC was then blended with sodium alginate (NaAlg) to prepare pH-sensitive interpenetrating network (IPN) microspheres (MPs) by emulsion-crosslinking method using glutaraldehyde (GA) as a crosslinking agent. The produced MPs are almost spherical in nature with smooth surfaces. Diclofenac sodium (DS), an anti-inflammatory drug, was successfully encapsulated into the MPs. The % encapsulation efficiency was found to vary between 54 and 67. The MPs were characterized by DSC, SEM and FTIR spectroscopy. In vitro release studies were carried out in simulated gastric fluid of pH 1.2 for 2h followed by simulated intestinal fluid of pH 7.4 at 37°C. The release data have been fitted to an empirical equation to investigate the diffusional exponent (n), which indicated that the release mechanism shifted from anomalous to the super Case-II transport.

Synthesis and characterization of chitosan-based pH-sensitive semi-interpenetrating network microspheres for controlled release of diclofenac sodium.

pH-Sensitive semi-interpenetrating networks (IPNs) based on chitosan (Cs) and acrylamide-grafted hydroxyethylcellulose (AAm-g-HEC) were prepared in the form of microspheres (MPs) by emulsion-crosslinking technique using glutaraldehyde (GA) as a crosslinker. Diclofenac sodium (DS) drug was successfully encapsulated into IPN microspheres by varying the ratio of Cs and AAm-g-HEC, % drug loading, and amount of GA. DS encapsulation of up to 83% was obtained as measured by UV spectroscopy. MPs with average particle sizes in the range of 188-310microm were obtained. MPs were characterized by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Differential scanning calorimetry (DSC). Diffusion coefficients (D) of water transport through the microspheres were determined using an empirical equation. In vitro release of DS from these matrices has been investigated in pH 1.2 and 7.4 media.