HPLC method for simultaneous analysis of ticagrelor and its organic impurities and identification of two major photodegradation products.

A simple, fast and sensitive analytical method by high-performance liquid chromatography (HPLC) was developed and validated for the simultaneous determination of ticagrelor and two synthesis impurities. The HPLC method was established using an Agilent 1200 Series equipment coupled to photodiode array detector (PDA) at 270nm with a Zorbax Plus C8 column (150×4.6mm, 5.0µm), injection volume of 20µL, and a constant temperature of 25°C. The mobile phase consisted of acetonitrile: ammonium acetate 50mM (57:43, v/v) and pH adjusted to 8.2 with ammonium hydroxide 6M, at a flow rate of 0.7mL/min. No interference peaks from excipients and diluent system indicated the specificity of the method. The calibration curves showed determination coefficients (r2)>0.99, calculated by linear regression. The limit of quantitation (LOQ) for impurities 1 and 2 were 2.0 and 0.2µg/mL, respectively. Intra and interday relative standard deviations (RSDs) were <2% for ticagrelor and <6% for the impurities, proving the precision of the method. Besides, two mayor degradation products formed when sample solutions of ticagrelor were exposed to UVC radiation were elucidated and the mechanisms involved in the photolytic degradation of ticagrelor were proposed.

Free radical scavenging in vitro and biological activity of diphenyl diselenide-loaded nanocapsules: DPDS-NCS antioxidant and toxicological effects.

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.