Evaluation of monolithic HPLC columns for various pharmaceutical separations: method transfer from conventional phases and batch to batch repeatability.

Methods developed on conventional particle-packed C18 columns for pilocarpine, propranolol, glibenclamide, glimepiride, insulin and their respective degradation products or related compounds were transferred from the conventional Superspher 100RP-18e column to Chromolith Performance RP-18e columns. All transfers were successful applying the same chromatographic conditions, except for insulin where the acetonitrile content of the mobile phase was reduced by 0.5%. The intraday and interday precisions for both retention time and peak area were evaluated over a wide concentration range. Results were found to be equal, or slightly better on Chromolith Performance with RSD%<1.1% in all cases. Monolithic batch to batch repeatability of both retention time and peak area, compared for monolithic columns from different batches gave an RSD% of less than 1.3%. The separation of each drug and its related products was investigated on monolithic columns at flow rates from 1 to 9 ml/min, and superior resolution was always obtained using monolithic over conventional columns at the same flow rate. A total of seven monolithic columns from four different batches were used in this study.