4. Conclusions
Curcumin was formulated into microemulsions to improve its
oral bioavailability. The physical nature of these systems, mechanism
of drug entrapment, as well as the physicoechemical interactions
of constituents determined drug solubilization capacity
and physical stability during storage and upon dilution.
The optimized formulation was obtained with vitamin E (3.3 g/
100 g), Tween 20 (53.8 g/100 g), ethanol (6.6 g/100 g) and water
(36.3 g/100 g). It resulted the best in terms of size, polidispersity,
encapsulation efficiency and positive influence on the solubility of
curcumin, that was increased approximately 10,000 fold compared
to its water solution. The microemulsion can be diluted with
aqueous buffer and it was stable for at least two months. The
optimized microemulsion showed a maximum solubility of curcumin
of 14.57 mg/ml and a percentage of permeation through the
artificial membrane of about 10% of curcumin after 6 h and about
70% after 24 h.
The results have significant and potential relevance for future
pharmacological applications, in particular for the preparation of a
possible dietary supplement for pediatric administration. In fact,
the developed formulation allows to obtain a very high solubility of
curcumin, able to meet the ADI of this molecule fixed by EFSA in
0e3 mg/kg by/day