Determination of the content of pregabalin gastric retention sustained- release tablets and influence of high viscosity excipients on the determination results

A high-performance liquid chromatographic (HPLC) method for the assay of pregabalin gastric retention sustained-release tablets was established, successfully solving the problem of low recovery of pregabalin through a special sample pretreatment method. By comparing salting-out and excipient dispersion, the pretreatment methods to overcome the viscosity of the test solution were established. Both methods can be used for the determination of the product content, but the salting-out method is easier to operate. The HPLC conditions were Inertsil ODS-3 (4.6 mm×0.25 m, 5 µm) column with mobile phase of 3.4 g/L potassium dihydrogen phosphate (pH adjusted to 6.3 by ammonia) and methanol (85︰15);the column temperature was 30 ℃;the flow rate was 1.0 mL/min;the sample size was 50 µL;and the detection wavelength was 210 nm. Through the validation of the salting-out method, the average recovery of the drug was 99.74% and the RSD was 0.43%; the precision test RSD was 0.77%;the test solution was stable within 12 h;the chromatographic system had good durability;and the excipient did not interfere with the content detection.The method is stable, reliable and suitable for the assay of pregabalin gastric retention sustained release tablets.