AAPS PharmSciTech

, Volume 10, Issue 1, pp 193–198 | Cite as

Preparation and Application of Carboxymethyl Yam (Dioscorea esculenta) Starch

  • Nattawat Nattapulwat
  • Narumol Purkkao
  • Ornamphai Suwithayapan
Research Article


Yam (Dioscorea esculenta) starch was modified by carboxymethylation. The effect of reaction parameters, amount of sodium hydroxide (NaOH), amount of sodium monochloroacetate (SMCA), and reaction time on the degree of substitution (DS) of carboxymethyl yam starch (CMS), was studied using the Box–Behnken experimental design. Physicochemical and potency to be a tablet disintegrant of CMS were evaluated. CMS with DS in the range of 0.08–0.19 were obtained. The results from regression analysis indicated that the most important factor in controlling DS was the amount of NaOH followed by SMCA content and reaction time. However, high concentration of NaOH and SMCA lowered the DS. The optimal conditions to achieve the highest DS (0.19) were found to be at molar ratios of NaOH and SMCA to anhydroglucose unit of 1.80 and 2.35, respectively, and with the reaction time of 4.8 h. The swelling power and viscosity of CMS increased with an increase in the degree of modification. CMS showed satisfying tablet disintegrant properties. The tablets containing 1.0–4.0 % CMS disintegrated faster than 5 min. Hence carboxymethyl yam starch can be used as an excellent tablet disintegrant in low concentration.

Key words

carboxymethyl yam starch Dioscorea esculenta disintegrant optimization yam starch 


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Copyright information

© American Association of Pharmaceutical Scientists 2009

Authors and Affiliations

  • Nattawat Nattapulwat
    • 1
  • Narumol Purkkao
    • 2
  • Ornamphai Suwithayapan
    • 1
  1. 1.Department of Pharmaceutical Technology, Faculty of PharmacySilpakorn UniversityNakhonpathomThailand
  2. 2.Department of Chemistry, Faculty of ScienceSilpakorn UniversityNakhonpathomThailand

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