Performance of alginate films for retention of l-(+)-ascorbic acid

DE NOBILI MD; CURTO LM; DELFINO JM; SORIA M; FISSORE EM; ROJAS AM

INTERNATIONAL JOURNAL OF PHARMACEUTICS

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2013 vol. 450 p. 95 - 103

0378-5173

In view of acting as controlled delivery systems for nutritional supplementation, therapy or antioxidantactivity at interfaces, alginate films of different copolymer composition and glycerol plasticizer levelswere developed in the presence of Ca2+ for achieving higher stability of l-(+)-ascorbic acid (AA). Theability of the alginate network to preserve AA from hydrolysis, tested by storage under vacuum at 25 ◦C,only decreased with the relative humidity (RH) increase when alginates were mainly constituted byguluronic?guluronic acid blocks (GG), whereas also decreased with the glycerol level increase whenmannuronic?mannuronic acid (MM) and/or alternating guluronic?mannuronic (GM + MG) flexible blockswere present in higher proportions. This result could be probably related to the lower capability of thelatter alginate block compositions to immobilize water in the network as they are not able to constituteCa2+ mediated junction zones where water molecules are highly retained. Films also studied under airstorage showed that even at less favorable conditions of RH and glycerol levels, both GG and GM + MGenriched alginate networks in general preserved AA from oxidation. It also demonstrated that hydrolysisis the principal way by which AA is lost when supported in films.