RESUMO
We reported the physical chemical characterization of a new series of native dextran (B110-1-2). The chemical structure of the polymer was characterized by IR, (1)H and (13)C NMR spectroscopy and compared with that of a commercial native dextran B512-F obtained from Sigma Company. Molecular weights of the product and different commercial dextran fractions of Leuconostoc mesenteroides from 43000 to 170000 average molecular weight (M(w)) were established by the analysis of intrinsic viscosity in aqueous solutions and compared with those obtained by gel permeation chromatography (GPC). The critical overlap concentration around 9g/L was obtained. No interactions of powder mixtures with different commercial excipients (lactose, cetyl alcohol, HPMC) and drugs (propranolol hydrochloride, acetyl salicyclic acid, isosorbide dinitrate, lobenzarit disodium, and nifedipine) were demonstrated by differential scanning calorimetry (DSC) analysis. Tablets obtained by direct compression showed good physical-mechanical and technological properties. Dextran B110-1-2 has similar physical chemical properties as commercial Sigma B512-F. Water uptake, erosion and dissolution profile studies for dextran tablets established that glucose polymer with molecular weight M(w) > or = 2x10(6) is suitable for the development of controlled release solid dosage forms (soluble drugs). Fraction of dextran (M(w) 40000-170000) could be more useful for immediate release tablets.