Over the past years, organoselenium compounds have been aimed as targets of interest in organic synthesis. Diphenyl diselenide [(PhSe)2] is an important example of this class showing several pharmacological properties. However, the poor water-solubility and its low oral bioavailability may be considered an obstruction for the clinical utility of this compound. For this reason, the use of nanocapsules is a prominent approach to increase the bioavailability of lipophylic molecules. This study aims to prepare diphenyl diselenide-loaded nanocapsules with two different concentrations, by interfacial deposition of the preformed polymer in order to develop a system to improve its oral bioavailability. The drug-loaded nanocapsules with 1.56 and 5 mg ml−1 and unloaded nanocapsule suspensions presented macroscopic homogeneous aspect, as well as submicronic sizes, low polydispersity, negative zeta potentials and slightly acid or neutral pH values. The biological tests of selenium distribution in different tissues of mice show a higher bioavailability of the (PhSe)2 nanocapsules when compared with the free (PhSe)2, both administered by per oral route at the dose of 50 mg/kg, showing a prominent influence of the nanocarries systems for biological properties of this organochalcogenium compound.

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Selenium compounds, such as diphenyl diselenide (DPDS), have been shown to exhibit biological activity, including antioxidant effects. However, the use of DPDS in pharmacology is limited due to in vivo pro-oxidative effects. In addition, studies have shown that DPDS-loaded nanocapsules (DPDS-NCS) have greater bioavailability than free DPDS in mice. Accordingly, the aim of this study was to investigate the antioxidant properties of DPDS-NCS in vitro and biological activity in mice. Our in vitro results suggested that DPDS-NCS significantly reduced the production of reactive oxygen species and Fe(II)-induced lipid peroxidation (LPO) in brain. The administration of DPDS-NCS did not result in death or change the levels of endogenous reduced or oxidized glutathione after 72 hours of exposure. Moreover, ex vivo assays demonstrated that DPDS-NCS significantly decreased the LPO and reactive oxygen species levels in the brain. In addition, the highest dose of DPDS-NCS significantly reduced Fe(II)- and sodium nitroprusside-induced LPO in the brain and Fe(II)-induced LPO in the liver. Also, δ-aminolevulinate acid dehydratase within the brain was inhibited only in the highest dose of DPDS-NCS. In conclusion, our data demonstrated that DPDS-NCS exhibited low toxicity in mice and have significant antioxidant characteristics, indicating that nanoencapsulation is a safer method of DPDS administration.

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Vildagliptin (VLG) corresponds to a drug used for the treatment of diabetes mellitus. This disease requires continuous treatment, and so the control of impurities present in it is important to assure the quality of this drug. Thus, it is necessary to use sensitive and selective detection techniques and the ultra-performance liquid chromatography is a better option compared with high-performance liquid chromatography because it enhances the separation efficiency with a shorter analysis time and an increased resolution. This research analysis was accomplished by using liquid chromatography/tandem mass spectrometry, and the quantification was performed by using an extracted ion from the VLG drug and its main organic impurities of synthesis. During the validation process, following international standards, the method proved to be linear for the tree substances (R2 = 0.997–0.998) and the analysis of variance showed a non-significant linearity deviation (P > 0.05). Three critical factors were selected to evaluate method robustness with a full factorial experimental design, and the changes in the parameters were found to be not significant for the quantification of VLG and its impurities. The ultra-performance liquid chromatography-tandem mass spectrometry for the determination of impurities in VLG was precise, accurate and robust proving to be effective for analysis in the pharmaceutical industry and to improve the quality, safety and effectiveness of the new drug developed.