Determinations of tiodazosin and levulinic acid from tablets by high-performance liquid chromatography

Specific assays of tiodazosin and levulinic acid from tablet preparations were developed using high-performance liquid chromatography. Tiodazosin was determined with acetonitrile 50% (v/v) in pH 5.7 acetate buffer on a 300 X 3.9-mm i.d. microparticulate C-18 column using 254 nm detection with butylparaben as the internal standard. Levulinic acid was determined at 280 nm with 1 N acetic acid on a 300 X 3.9-mm i.d. microparticulate phenyl column using an external standard. The assays were run sequentially. The relative standard deviations of sample variability (2 sigma, n = 6) and recoveries from synthetic preparation were +/- 1.6 and approximately 95%, respectively, for both assays.