590 and 1.330, respectively. The data were analysed by Mastersizer 2000 5.54 software programme. The span values were determined by dividing the difference between D0,1 and D0,9 by D0,5, as provided by the software. The use of DLS and LD was applied as a good means to evaluate changes during this website storage because Zetasizer nano ZS® and
Mastersizer 2000® are able to determine particle sizes ranging from 0.003 to 10 μm and from 0.02 to 2000 μm, respectively. The results were evaluated by a one-way analysis of variance (ANOVA) and the mean values analysed by Tukey’s test using the STATISTICA® 8.0 software programme. The purity of the bixin standard was 98.7 ± 0.20%. This value is similar to the values reported by Rios and Mercadante, 2004 and Rios et al., 2009 and Barbosa et al. (2005) who observed purity levels of 98%, 96% and 94%, respectively. These values indicate that the type of solvent and the characteristics of extraction, such as crystallisation and temperature,
Everolimus affect the final purity in terms of bixin. The bixin standard was produced with a yield of 0.86 ± 0.03% as a result of the washing procedures performed to increase the purity. The standard formulation of nanocapsules applied in this study was chosen because as the polymer PCL is biocompatible, biodegradable, and does not generate toxic compounds; moreover, it is approved by FDA (Food and Drugs Administration) for specific studies and has similar costs compared to other Fludarabine order synthetic polymers. Moreover, this formulation was studied in various pharmaceutical experiments of drug delivery (Jäger et al., 2009, Paese et al., 2009 and Pohlmann et al., 2002). This formulation was optimised by Venturini et al. (2011) in a study in which aqueous suspensions composed exclusively of lipid-core nanocapsules were formulated, and allows the controlled release of its core content in the gastrointestinal tract (Frozza et al., 2010). Preliminary
tests were conducted to produce suspensions composed only of bixin nanocapsules with diameters smaller than 1 μm and exhibiting a monomodal size distribution. The formulations were analysed by laser diffraction over a period of 3 weeks. In the study, five formulations denoted 1–5 and containing bixin concentrations of 100, 58, 37, 16 and 11 μg/mL, respectively, were produced. Immediately after the preparation, formulation 1 (100 μg/mL) showed bixin crystals in suspension. The crystallisation process was induced by high-purity bixin, which resulted from the high concentration of the bixin standard. Formulation 2 (58 μg/mL) showed a bimodal size distribution, with particle sizes ranging from the nanometre to the micrometre scale (Fig. 2a). Differently, formulation 3 (37 μg/mL) showed a good monomodal distribution profile, a volume-weighted mean diameter (D4,3) of 151 nm and a span value of 1.284; moreover, 90% of the nanocapsules had diameters (D0,9) smaller than 115 nm.