STRUCTURAL PROPERTIES OF BENZNIDAZOLE LOADED O/W
NANOEMULSION
DA SILVA-JÚNIOR, Arnóbio Antônio1, STRECK, Letícia 1*, ARAÚJO, Margarete
Moreno1, SOUZA, Izadora2,
1. Programa de Pós-graduação em Ciências Farmacêuticas, Universidade Federal do Rio
Grande do Norte, UFRN, Natal, RN, Brazil
2. Curso de Farmácia, UFRN, Natal, RN, Brazil
*[email protected], [email protected]
Aim: Evaluating of the effect of surfactant/oil phase ratio in the benznidazole (BNZ)
loading and structural properties of the oil-in-water nanoemulsions (NE) using
rheological measurements. Methods: NE were prepared using medium chain
triglyceride (MCT) as oil phase (OP) and a surfactant mixture (SM) composed by soy
phosphatidylcholine and sodium oleate in a ratio of 1:7 (w/w) using ultrasound stirring.
SM/OP ratio was ranged from 0.5 to 2.5. Rheology trial included flow behavior which
was carried out in MCR302 Anton Paar rheometer equipped with cone-plate geometry,
with titanium cone geometry (cone angle 1°) had 5 cm of diameter and gap of 102 m.
The flow behavior of samples was identified in a shear rate range between 0.25 to 100 s1
to ascending curve and 100 to 0.25 s-1 to descending curve at 25 °C controlled by
Peltier cell with an analysis time of 5 minutes. The droplet size analysis was carried out
with Zeta Plus Particle Sizing on 660 nm wavelength at 25 °C and fixed angle 90 º.
Results: The OP rising in NE did not lead to structural changes. All NE studied
showed Newtonian flow behavior including the NE loaded with BNZ. The drug loading
has remained about 0.12% and displaying increase on BNZ-loaded compared with its
water solubility. The presence of drug showed that none change was observed in
structural properties. The BNZ-free NE presented droplet size which ranged between
110 to 130 nm and the for BNZ-loaded NE among 81 to 164 nm. Cross-polarized light
microscopy displaying isotropic behavior for all NE studied. NE based MCT increased
benznidazole soluble fraction about six times.
Key-words: nanoemulsions, medium chain triglyceride, benznidazole, rheology,
structural properties.
Financial support: CAPES (Streck, L., Araujo, M.M), CNPq (Number: 479195/2008-0
and 483073/2010-5), PPgCF-UFRN, UFRN.