Effect of cross-linked biodegradable polymers on sustained release of sodium diclofenac-loaded microspheres

The objective of this study was to formulate an oral sustained release delivery system of sodium diclofenac(DS) based on sodium alginate (SA) as a hydrophilic carrier in combination with chitosan (CH) and sodium carboxymethyl cellulose (SCMC) as drug release modifiers to overcome the drug-related adverse effects and to improve bioavailability. Microspheres of DS were prepared using an easy method of ionotropic gelation. The prepared beads were evaluated for mean particle size, entrapment efficiency, swelling capacity, erosion and in-vitro drug release. They were also subjected to various studies such as Fourier Transform Infra-Red Spectroscopy (FTIR) for drug polymer compatibility, Scanning Electron Microscopy for surface morphology, X-ray Powder Diffraction Analysis (XRD) and Differential Scanning Calorimetric Analysis (DSC) to determine the physical state of the drug in the beads. The addition of SCMC during the preparation of polymeric beads resulted in lower drug loading and prolonged release of the DS. The release profile of batches F5 and F6 showed a maximum drug release of 96.97 ± 0.356% after 8 h, in which drug polymer ratio was decreased. The microspheres of sodium diclofenac with the polymers were formulated successfully. Analysis of the release profiles showed that the data corresponds to the diffusion-controlled mechanism as suggested by Higuchi

Rhéologie des billes de gel d'alginate et étude de l'effet de la déshydratation/rehydratation sur la structure

Rhéologie des matériaux pour les industries agro-alimentaires, cosmétiques et pharmaceutiquesNational audienc

Physico-chemical properties and rheology of alginate gel beads formed with various divalent cations

The physico-chemical parameters influencing the behaviour of alginate beads have not been deeply studied in the literature. In this communication, the formation and the mechanical and structural properties of alginates with different molecular weights and M/G ratio were investigated. The results obtained showed that (1) to produce spherical beads, the product of alginate concentration and intrinsic viscosity C[eta] must be higher than a threshold value and the accurate value is a function of the gelling cation type; (2) the nature of the cation, the polymer and cation concentration, and the ionic strength influence the mechanical properties of alginate beads; (3) critical point drying and cryogenic preparation are equivalent and less disturbing methods than lyophilization for studying the structural properties of alginate beads in SEM; and (4) calcium-alginate beads are smooth and uniform whereas copper-alginate beads are rough and seem to be formed of associations of independent microgels. (C) 1999 Elsevier Science Ltd. All rights reserved

Rhéologie des billes de gel d'alginate et étude de l'effet de la déshydratation/rehydratation sur la structure

National audienc

Bekuse

Traditional dance song accompanied by a dru

Sorption of benzene in cation-exchanged zeolite X, as measured by muon spin relaxation (LF-μSR)

Proton NMR relaxation, diffusion and microimaging techniques were used to investigate the internal structure of calcium alginate gel beads formed by dripping a sodium alginate solution into a calcium chloride solution. It is shown that many of the pore structures previously reported are probably artefacts of sample preparation. Evidence is presented for a non-uniform calcium alginate concentration profile even in beads that have been 'equilibrated' in calcium chloride solution for over 24 h. It is found that the internal structure depends on the ratio of calcium and alginate concentrations and a microstructural phase diagram can be constructed. Copyright (C) 2000 John Wiley & Sons, Ltd

Ilongo manga

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Baningi bayni ngai

Fox-trot dance song accompanied by various instrument