Abstract:In this article, Sodium alginate and Lignosulphonic acid blends were prepared in different weight ratios by solution casting method. Swelling experiments were conducted for Sodium alginate and its blends by adding calcium chloride for various intervals in a pH 7.4 medium. The strength of the films increases after their treatment with CaCl 2 at higher intervals forming an alginate network. The SA/LS blend (80/20) is subjected for sorption studies at variable pH 1.2 & 7.4, in order to test the suitability of the blends for controlled drug delivery. Further, experiments were conducted for de-crosslinking using 0.1M HCl. The solvent uptake for the blends decreased with increasing LS content in the blends. Blends were investigated by X-ray diffraction and Fourier Transform Infra-Red spectroscopy in order to study the crystallinity and molecular interactions. XRD confirms the reduction in cluster space in blends leading to lower uptake of solvent.

Blends of sodium alginate (SA) and lignosulphonic acid (LS) has been prepared in the ratio of 80/20. The prepared blends were crosslinked using chlorides of calcium, barium, strontium and aluminum. The crosslinking of blends was done for different time intervals and then these blends were subjected for swelling studies in aqueous medium of pH 7.4. The observations indicate that the crosslinking is diffusion controlled and is affected by the size of metal ion and the type of alginate used. The improved swelling time for crosslinked blends in aqueous medium supports the fact that the stability under physiological conditions of the blends is improved due to crosslinking with the metal ions. Calcium chloride and barium chloride forms strong crosslink with the blend. Calcium ion crosslinked blends can be considered suitable for biomedical drug applications. The investigations on crosslinked blends using FTIR, SEM, XRD and EDAX are in close agreement with swelling results.

The ciprofloxacin (CPX)-loaded blends made of sodium alginate and lignosulfonic acid (LS) were prepared by solution casting method in the ratio of 80/20. The blends were crosslinked for different intervals of time to control the drug release. The drug release was investigated for 24 hours in different pH medium (1, 4, 7, and 9). It was confirmed that drug release is controlled by diffusion through the polymer matrix followed by the erosion of the polymer. The pH of the surrounding medium influences the drug solubility, swelling, and degradation rate of the polymer and therefore the overall drug release process. The blend shows minimal drug release at pH 1 and 9, whereas moderate release at pH 4, but rapid release at pH 7. Further FTIR, XRD, and SEM characterization are carried, to confirm the chemical-interaction, crystallization effects, and compatibility between the blend matrixes. V C 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40442.

Sodium alginate and lignosulfonic acid blends were prepared in various ratios (100=0, 80=20, and 60=40), in order to test the suitability of these blends for controlled drug delivery in variable pH medium using barium chloride as crosslinking agent. The blends were characterized by TGA and DSC, in order to study thermal degradation properties and glass transition temperature. Thermal analyses of blends were found to be degrading in multiple steps compared to their pure polymers. Crystallization characteristics are investigated using the DSC curves. Further, miscibility of blends was investigated for morphological studies by SEM.

Diffusion and sorption of Biodegradable blends of sodium alginate (SA) and lignosulphonic acid (LS) has been studied at room temperature by conventional weight gain experiments. The sorption studies of SA/LS blends are carried in pH medium of 7.4. The sorption data are used to evaluate the mass transfer coefficients such as intrinsic diffusion coefficient and permeation coefficient. It was observed that the blends follow Fickian mode of transport where polymer chain relaxation is more than diffusion of solvent.