Improved Dissolution Method of Loratadine Tablets

OBJECTIVE To improve a test method for the dissolution of loratadine tablets to inspect the determination of loratadine tablets from 31 factories in China. METHODS According to loratadine tablets’ speciality of dissolution and absorption, set a discriminating specification for dissolution testing, using two points for biopharmaceutics classification system Ⅱ drugs’ assessment. The dissolution was determined by paddle method, the medium was pH 3.0 buffer solution, and rotate speed was 75 r·min^-1. The chromatographic condition was Agilent TC-C₁₈(4.6 mm×250 mm, 5 μm) column, the mobile phase consisted of acetonitrile and water(0.5% diethylamine adjusted to pH 3.0 with phosphoric acid) (60∶40), the wavelength of UV detector was 247 nm; the flow rate was 1.0 mL·min^-1, the injection volume was 20 μL. RESULTS The calibration curve was liner in the concentration range of 1.006-32.176 μg·mL^-1, r=1.000; several samples from 31 factories were detected using this method and the fraction defective was 74.7%. CONCLUSION The improved method shows more biological availability than before, and the assay method is accurate, highly specific and widely applicable. Through the investigation of samples from the whole country, it is shown that the method developed can be applicable to all the samples and effectively control the internal-quality of product.