Industrial Crops and Products 41 (2013) 324–330 Contents lists available at SciVerse ScienceDirect Industrial Crops and Products journa l h o me pag e: www.elsevier.com/locate/indcrop Characterization of sodium starch glycolate prepared using reactive extrusion and its comparisons with a commercial brand VIVASTAR ® P Pratik N. Bhandari a , David D. Jones b , Milford A. Hanna c,∗ a University of Nebraska-Lincoln, Department of Biological Systems Engineering, 156 L.W. Chase Hall, Lincoln, NE 68583-0730, United States b University of Nebraska-Lincoln, College of Engineering, 114F Othmer Hall, Lincoln, NE 68588-0642, United States c University of Nebraska-Lincoln, Industrial Agriculture Product Center, 211 L.W. Chase Hall, Lincoln, NE 68583-0730, United States a r t i c l e i n f o Article history: Received 14 February 2012 Received in revised form 23 April 2012 Accepted 29 April 2012 Keywords: Sodium starch glycolate Reactive extrusion Super-disintegrants VIVASTARP Pharmaceutical excipients a b s t r a c t Reactive extrusion is a popular technique for chemical modification of starches. In this study, the physical, chemical and morphological properties of sodium starch glycolate, prepared using reactive extrusion (SSG), were compared with those of VIVASTAR ® P. As measured by sieve analysis, VIVASTAR ® P had a larger weight fraction in the particle size range of 0–38 m compared to SSG. The sodium assays of VIVASTAR ® P and its particle size fractions (0–38 m and 38–75 m) were found to be significantly lower than those of SSG and its particle size fractions (0–38 m, 38–75 m and 75–106 m). The NaCl content, pH, settling volume, bulk density, tap density and Carr index for VIVASTAR ® P and SSG were measured. X-ray diffraction patterns indicated substantial loss of crystallinity of starch in both VIVASTAR ® P and SSG. The water uptakes of the 0–38 m and 38–75 m fractions of VIVASTAR ® P, measured at 20 and 180 s, were significantly higher than those for the 0–38 m and 38–75 m fractions of SSG. However, no differences were found between the water uptakes of both the VIVASTAR ® P fractions and the 75–106 m fraction of SSG at 20 s. However, the water uptake of the SSG 75–106 m fraction leveled off as time progressed. When, 0.1 N HCl was used, at an interval of 20 s, the SSG 75–106 m and 38–75 m fractions had significantly higher liquid uptake than VIVASTAR ® P and its 0–38 m fraction. However, no significant differences were found between the liquid uptakes of the SSG 75–106 m and 38–75 m fractions and the VIVASTAR ® P 38–75 m fraction. After a time interval of 180 s, the liquid uptakes of the SSG 75–106 m and 38–75 m fractions were significantly lower than those for VIVASTAR ® P and its 0–38 m fraction. The liquid uptake of the VIVASTAR ® P 38–75 m fraction was higher than that of the SSG 38–75 m fraction but not significantly different from the SSG 75–106 m fraction. The microstructure of VIVASTAR ® P revealed the presence of spherical and ovoid shaped particles with smooth surfaces. This was in contrast with the irregular shaped particles of SSG with jagged surfaces. © 2012 Elsevier B.V. All rights reserved. 1. Introduction Disintegrants are substances present in tablet formulations that promote their dispersion and result in the release of the drug. Native starch has historically been used in disintegrant applica- tions in oral solid dosage forms (Shah and Augsburger, 2002). However, at the required amounts, native starch does not achieve required tablet compactibility (Augsburger et al., 2007; Bolhuis et al., 1984). To improve the efficiency of disintegration, a new class of ‘superdisintegrants’ was developed. These superdisinte- grants include products like sodium starch glycolate, crospovidone and croscarmellose sodium. ∗ Corresponding author. Tel.: +1 402 472 1634; fax: +1 402 472 6338. E-mail addresses: pbhandari2@unl.edu (P.N. Bhandari), djones1@unl.edu (D.D. Jones), mhanna@unlnotes.unl.edu, mhanna1@unl.edu (M.A. Hanna). Sodium starch glycolate is a popular disintegrant, prepared by cross-linking sodium carboxymethyl starch. Sodium car- boxymethyl starch is prepared by substituting the hydroxyl groups in the anhydroglucose units of starch molecules with sodium car- boxymethyl groups. The sodium carboxymethyl substitution is obtained by reacting starch with sodium mono chloro acetate in the presence of NaOH. Impurities formed during the reaction, like sodium glycolate, sodium chloride and sodium citrate, are partially removed from the product after the reaction. Disintegration of orally administered solid dosage forms gen- erally takes place in the gastro-intestinal tract. There is no single mechanism which can explain the disintegration behavior of sodium starch glycolate. The important proposed mechanisms of disintegration include liquid wicking, swelling and deformation recovery. Liquid wicking is considered to be a crucial first step for tablet disintegration. For sodium starch glycolate, a larger rate and extent of water uptake has been observed to have resulted in faster disintegration (Augsburger et al., 2007). Swelling is the most 0926-6690/$ – see front matter © 2012 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.indcrop.2012.04.050