Tese
Desenvolvimento e avaliação biológica de preparações nanoestruturadas de desonida para uso tópico
Fecha
2018-08-27Autor
Rosa, Priscila
Institución
Resumen
Topical corticosteroid are widely used in dermatology. However, the therapy with these drugs
has some limitations related to the treatment duration and to drug potency, that may cause
undesirable effects. Nanoparticulate systems have been considered alternatives for the drug
control release, targeting to the specific site of action and reducing the adverse effects. In this
context, the objective of this study was to prepare nanotechnologic-based semisolid
formulations containing desonide, aiming to obtain applicable formulations for the treatment
of dermatological diseases. Polymeric nanocapsule suspensions were prepared, employing the
polymer Eudragit® RL 100, açai oil (AO) or medium chain triglycerides (MCT) as oily core
and the drug at 0.25 mg mL-1
. Formulations containing AO presented mean particle size of
165 nm, and those prepared with MCT mean particle size around 131 nm. Both showed
polidispersity index (PDI) < 0.2, acid pH, drug content near to the theoretical value,
encapsulation efficiency of 81% and positive zeta potential. Direct exposure of the
nanocapsule suspensions to UVA and UVC radiations showed that the colloidal systems were
effective in protecting desonide from photodegradation and that the formulations containing
açai oil presented greater photostability. In vitro phototoxicity study indicated that at
concentration of 0.5 mg mL-1
, formulations did not present phototoxic potential in 3T3
murine fibroblasts and human keratinocytes using MTT and NRU cell viability assays. The
nanostructured hydrogels were prepared by dispersing the Amigel®
polymer (sclerotium gum)
directly into the colloidal suspensions. Semisolids presented pH compatible with topical
application, drug content around 0.25 mg mL-1
, and maintained the nanostructures. Regarding
the flow properties, hydrogels presented non-Newtonian pseudoplastic flow, according to
Ostwald model. The skin permeation/penetration study with the nanostructured hydrogels
showed the drug reached the site of action of topical corticosteroids. Biological activity of the
preparations was evaluated using a croton oil-induced dermatitis model and indicated that the
nanostructured hydrogels had comparable effect to the commercially available formulation of
desonide.