2.5 Kinetic determination2.5.1 Kinetic investigation of FVS in acid degradationThe kinetics of acid degradation of FVS was evaluated in 0.1 M HCl at 70°C for different periods of time. Solutions containing 1 mg/mL of FVS were prepared in water. An appropriate aliquot was transferred to a volumetric flask and diluted with 0.1 M HCl to give a final concentration of 100 µg/ml FVS. This solution was heated to 70°C and evaluated for time intervals of 30 min, 60 min and 120 min. Three samples were analyzed for each time interval. After the required time, collected 1 ml aliquots were transferred to a 10 ml volumetric flask and neutralized with 1 ml of 0.1 M NaOH using a pH meter. This solution was diluted with a mobile phase to 20 μg/ml FVS solution for HPLC analysis. The kinetic determinations were carried out in the dark to exclude the possible degradation effect of light.2.5.2 Kinetic investigation of FVS in oxidative degradationThe kinetics of acidic degradation of FVS was evaluated in 3% H2O2 at 70 °C for different periods. Solutions containing 1 mg/mL FVS were prepared in water. An appropriate aliquot was transferred to a volumetric flask and diluted with 3% H2O2 to give a final concentration of 100 µg/ml FVS. This solution was heated to 70°C, evaluated for time intervals of 30 min, 60 min and 120 min. Three samples were analyzed for each time interval. After the required time, collected 1 ml aliquots were transferred into a 10 ml volumetric flask and this solution was diluted with mobile phase to obtain 20 µg/ml FVS solution for HPLC analysis. The remaining FVS concentrations determined at the different time intervals in the kinetic determinations were used in the plots. The plots were concentrated...... middle of paper......:119-126 (2005).22. W. Aman, K. Thoma, International Journal of Pharmaceutics 243: 33-41 (2002).23. Onoue, Y. Tsuda, Pharmaceutical Research 23: 156-164 (2006).24. HH Tønnesen, International Journal of Pharmaceutics 225: 1–14 (2001).25. RH Clothier, Alternative to laboratory animals 35: 515-519 (2007).26. ICH Theme Q2 (R1), Validation of analytical procedures: text and methodology, Geneva, Switzerland, 2005.27. Bakshi, M., Singh, S., Journal of Pharmaceutical and Biomedical Analysis; 28; 1011-1040 (2002).28. Swartz, M., Krull, I., LC-GC; 23, 586-593 (2005).29. ICH-QA1 (R2); Stability tests of new medicinal substances and products, Geneva, Switzerland, 2003.30. Ahuja, SS, Medication Administration Screening; 59, 3-11 (2007).31. KA Connors, GR Amidon, VJ Stella, Chemical Stability of Pharmaceuticals, A Handbook for Pharmacists, 2nd ed., Wiley, New York, 1986.