Preparation of sodium alginate–methylcellulose blend microspheres for controlled release of nifedipine

Carbohydrate polymeric blend microspheres, consisting of sodium alginate (NaAlg) and methylcellulose (MC) were prepared by water-in-oil (W/O) emulsion method. These microspheres were cross-linked with glutaraldehyde and loaded with nifedipine (NFD), an anti-inflammatory drug. The microspheres were characterized by differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and laser particle size analyzer. DSC thermograms of NFD-loaded NaAlg–MC microspheres confirmed the molecular level distribution of NFD in the polymer matrix. SEM picture of the microspheres suggested the formation of spherical particles. Swelling experiments on the microspheres provided important information on drug diffusion properties. Release data have been analyzed using an empirical equation to understand the nature of transport of drug containing solution through the polymeric matrices. The controlled release characteristics of the matrices for NFD were investigated in pH 7.4 media. Particle size and size distribution of the microspheres was studied by laser light diffraction particle size analyzer. Drug was released in a controlled manner up to 12 h.