The stability of water-soluble modified starch iodophors

Abstract

Water-soluble starch derivatives were obtained by the oxidative destruction of native potato starch and cationic potato starch (DS = 0.06; 0.33; 0.66). High-performance liquid chromatography (HPLC) analysis revealed the molecular weight of such polysaccharides to decrease 30–500 times, and chemical analysis showed the appearance of new carbonyl and carboxyl groups up to 1.04 wt % and 0.2 wt %, respectively.

The UV-VIS spectrophotometric analysis proved soluble cationic starch derivatives to form non-stoichiometric polyelectrolite complexes with anionic iodine species and non-cationic soluble starch to form blue inclusion complexes with iodine.

Solutions of iodophor complexes having up to 10 wt % of iodine (according to the mass of iodophor) were formed. The stability of iodophors was compared with that of KI–I₂ and PVP–I₂ iodophors which are products widely used in medical applications. After 18 days of experiment, the highest stability was shown by soluble cationic starch (DS = 0.06) – iodine sample, where the loss of molecular iodine was up to 37 wt %. The loss of molecular iodine for soluble cationic starch (DS = 0.33) – iodine and PVP–I₂ samples was 80–85 wt %. The KI–I₂ solution showed the lowest stability, whereas no iodine was found after 7 days. The hydrolysis of iodine in the solutions of soluble cationic starch derivatives was 3–10 times faster as compared with that in KI–I₂ or PVP–I₂ solutions. The free iodine content was lowest in soluble cationic starch (DS = 0.06) and PVP–I₂ solutions; therefore, these two samples are considered to be most stable.

DOI: http://dx.doi.org/10.5755/j01.ct.63.1.4519