Determination of polyvinylpyrrolidone using high-performance liquid chromatography.

Polyvinylpyrrolidone (PVP) is a versatile polymer with innate surface activity. It is very difficult to accurately assay due to its wide molecular weight range and amphiphilic nature. This study evaluated a reversed-phase HPLC method to separate and quantify PVP K15. The assay used a Hicrome C18 150 mm x 3 microm HPLC column in combination with an 80/20 propanol-1-ol: deionised water, 0.01% TFA mobile phase, which resolved the polymer as a single peak, tR = 10.69+/-0.17 min (n=120) at 243 nm. The column's performance was constant throughout the study, N (theoretical plates) = 1729+/-22 and the peak symmetry remained good (As ranged from 0.74 to 0.92, n=10 over the calibration range). The developed assay proved to be accurate, sensitive and capable of recovering PVP K15 from pharmaceutical formulations. The limits of quantification and detection were calculated statistically as 2.40 and 0.72 mg ml(-1), respectively. Assay reproducibility assessed at five concentrations gave an average coefficient of variance <3.5% and the accuracy of the analytical method was 102.62+/-2.04%. The recovery of PVP K15 from directly compressed tablets and Refresh eye drops was 98.02+/-2.73 and 108.35+/-6.52%, respectively.