Comparison of two derivative spectrophotometric methods for the determination of alpha-tocopherol in pharmaceutical preparations

Simple, sensitive and reliable derivative spectrophotometric methods were developed and validated for determination of alpha-tocopherol in pharmaceutical preparations. The solutions of standard and the sample were prepared in absolute ethanol. The quantitative determination of the drug was carried out using the first derivative values measured at 284, 304 nm and the second derivative values measured at 288, 296 nm. Calibration graphs constructed at their wavelengths of determination were linear in the concentration range of alpha-tocopherol using peak to zero 10-250 microg ml(-1) for first and second derivative spectrophotometric methods. Developed spectrophotometric methods in this study are accurate, sensitive, precise, reproducible, and can be directly and easily applied to Evon dragee form as pharmaceutical preparation. Statistical analysis (Student's t-test) of the obtained results showed no significant difference between the proposed two methods.