Starch Derivatives of High Degree of Functionalization. 13. Novel Amphiphilic Starch Products

Abstract

Amphiphilic starch derivatives of high degree of substitution (DS) were prepared by benzylation of pea, potato and waxy maize starch followed by the introduction of hydroxypropyltrimethylammonium and carboxymethyl moieties. The conversions were carried out under heterogeneous conditions leading to products with a total DS of up to 1.8. The starch composition regarding amylose and amylopectin influences the DS value. The structure of the products was characterized by means of elemental analysis, FTIR and NMR spectroscopy, and, in case of benzyl carboxymethyl starch by means of HPLC after complete chain degradation. The tensioactive properties depend on the DS values of hydrophilic and lipophilic groups and can be adjusted by controlling the molar ratio anhydroglucose unit to reagent during the synthesis. Surface tensions as low as 48.6 mN/m were found for benzyl hydroxypropyltrimethylammonium starch and 38.6 mN/m for benzyl carboxymethyl starch. The lowest critical micelle concentration determined is 2.1 mmol/L.

Characterization of highly substituted, cationic amphiphilic starch derivatives: Dynamic surface tension and intrinsic viscosity

“…The MS value (the average number of moles of the substituent groups per repeating unit) of the HPMA groups was calculated from the nitrogen content obtained by elemental analysis according to Eq. and one obtained a total degree of substitution (MS N ) of up to 1.00. where M BnS is the molar mass of the modified repeating unit of benzyl starch and N (%) is the nitrogen content.…”

“…The MS value (the average number of moles of the substituent groups per repeating unit) of the HPMA groups was calculated from the nitrogen content obtained by elemental analysis according to Eq. (2) [29] and one obtained a total degree of substitution (MS N ) of up to 1.00.…”

Self-assembled micelles based on hydrophobically modified quaternized cellulose for drug delivery

“…In Table 1 Physiochemical properties of the hydrophobically modified quaternized celluloses (HMQCs) and theirs micelles. [32].…”

Carboxymethylation of kappa-carrageenan for intestinal-targeted delivery of bioactive macromolecules

“…Carboxymethylation of carbohydrates relies on maximizing the degree of substitution (Heinze, Rensing, & Koschella, 2007;Jin et al, 2006;Kooijman et al, 2003;Mohamadnia et al, 2007). However, water solubility of carboxymethylated carbohydrates increases with increasing substitution, and this increase in water solubility in turn reduces gelling properties (Kittipongpatana, Sirithunyalug, & Laenger, 2006;Lawal et al, 2007).…”