Automated high-pressure liquid chromatographic assay of robenidine hydrochloride.

High-pressure liquid chromatography has been applied to the separation and analysis of robenidine hydrochloride in the presence of its chemical precursors. It provides a rapid and specific method for the analysis of robenidine in technical material as well as feed premixes and is capable of distinguishing the intact drug from its degradation products. The chromatographic system employs a mixture of methanol, acetic acid, and methylene chloride as the mobile phase and a controlled pore glass as the stationary phase. Sample manipulation has been automated in 2 ways. In the first, manually prepared samples are automatically injected onto the column for separation and quantitation. In the second, a totally automated sample handling system, weighed samples are extracted, diluted, filtered, and then injected onto the column, all in a sequential manner. These procedures are capable of giving quantitative results at a rate of 10 samples/hr with a relative standard deviation of 1.13%.