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Studies on double emulsion (W/O/W) of iron aminoacid chelate.
Rubén Jiménez Alvarado, Gerardo Valerio Alfaro, José Alberto Monroy Rivera*
jamonroy@itver.edu.mx. UNIDA, Instituto Tecnológico de Veracruz
Double emulsions are meta-stable dispersions of water/oil/water type (W/O/W) or
oil/water/oil type (O/W/O). They are widely used in pharmaceutical applications. In
this work, the preparation conditions of a double emulsion W/O/W-type containing
water soluble iron aminoacid chelate were studied. The primary emulsion was
obtained at 25 000 rpm after 30 min of agitation. Three span 80 concentrations
were tested as W/O emulsifying agent (2, 17 and 32%). The secondary emulsion
was prepared at 600 rpm during 15 min. The hydroxipropilcellulose (5%) and
Sodium Lauryl Sulfate –SLS- (0.1, 1 and 10 the Critical Micelle Concentration,
CMC) were the emulsifiers for the secondary emulsion O/W. The double emulsion
was steady when span 80 concentration in the primary emulsion was 17% and the
SLS concentration in secondary emulsion was 10 CMC. The inner droplets mean
diameter was in the 0.25-0.47 µm range and the diameter of the external droplet
were between 15 and 30 µm. The water concentration was 90% in the W/O
primary emulsion and 10% in the secondary emulsion.
KEY WORDS. Double emulsion, iron aminoacid chelate, span 80, Sodium Lauryl
Sulfate
INTRODUCTION
Emulsions contain two immiscible
fluids like water and oil. The oil in
water dispersions are called direct
emulsions. The double emulsions can
be of type W/O/W or O/W/O 3,5,6,7 .
This structure of double compartment
has created great interest toward
multiple systems since his first
description in 1925 12 . At this time,
they were considered as a depot of
encapsulated substances that could
be released under different
conditions 8 . A more important number
of applications is encountered in
human pharmaceutics 2,11,12 . The
W/O/W emulsions have been tested
as a potential carrier of several
hydrophilic drugs (vaccines, vitamins,
enzymes, hormones) progressively
released 1 . Considering the
importance of iron in the biosynthesis
of vital molecules (hemoglobin,
miohemoglobin, metabolic enzymes,
etc.), there is a tendency to fortify
foods with iron, in some cases in
mixture with microelements and
vitamins. Iron is better absorbed as
chelate iron than the sulfate form 9 .
Besides, the biglicined iron has a high
potential as a food fortifier because
its absorption isn’t diminished by
precipitation, or by its linkage with
other molecules, like phytates.
However, biglicined iron increases
the oxidation of unsaturated fatty
acids more strongly than other
fortifiers and it has an unpleasant
flavour. The stability of the biglicined
iron is other disadvantage; it is easily
oxidized to its ferric form. These