POLYMORPHISM, CRYSTALLINITY AND HYDROPHILIC-LIPOPHILIC BALANCE (HLB) OF CETEARYL ALCOHOL AND CETYL ALCOHOL AS RAW MATERIALS FOR SOLID LIPID NANOPARTICLES (SLN)
Thallysson Carvalho Barbosa, Conrado Marques, Daniele Martins, Luciana Nalone, Salvana Costa, Kahynna Loureiro, Marco V. Chaud, Classius F. da Silva, Eliana B. Souto,*, Raquel de Melo Barbosa and Patrícia Severino*
ABSTRACT
The use of Solid Lipid Nanoparticles (SLN) has become a very popular approach in the development of innovative pharmaceutical drug delivery systems. The first step is the assessment the lipids’ suitability. This paper is focused on the physicochemical characterization of lipids, namely cetyl alcohol and cetearyl alcohol, for the production of SLN. The bulk lipids were analyzed by Differential Scanning Calorimetry (DSC) and Wide Angle X-ray Diffraction (WAXD) without any treatment, after tempering the raw materials (bulk lipid) for 1 hour at 80ºC, and after their spray-drying process. Hydrophilic Lipophilic Balance (HLB) values were determined using a combination of surfactants (polysorbate 20 and trioleate sorbitan) for the production of the hot o/w emulsion. Results of DSC and WAXD showed that after the thermal stress applied to the bulk lipids, both the melting point and the intensity of the refractogram peaks have decreased. Cetyl alcohol and cetearyl alcohol crystallized in more unstable polymorphic forms, which anticipate the suitability of these lipids for the production of SLN. The best HLB values obtained for the produced emulsions were 15.5, 16.0, and 16.7, combining accepted surfactants. The results showed that both cetearyl alcohol and cetyl alcohol are adequate lipids for the development of stable SLN.
Keywords: Cetearyl alcohol; cetyl alcohol; lipid polymorphism; hydrophilic lipophilic balance; solid lipid nanoparticles.
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