High pressure liquid chromatographic determination of atropine sulfate and scopolamine hydrobromide in tablets

A reverse phase high pressure liquid chromatographic (HPLC) system utilizing ion-pairing, similar to that previously reported for methscopolamine bromide, was developed for the quantitation of atropine sulfate and scopolamine hydrobromide in tablets. This HPLC system is capable of differentiating the major tropane alkaloids, with the exception of the atropine-hyoscyamine optical isomer pair, by their k' values and separating a significant degradation product, tropic acid. Optimum sensitivity is obtained by using a variable wavelength ultraviolet detector at 230 nm resulting in a detection limit of less than 0.5 microgram alkaloid/injection. The response is linear in the range of 3--19 microgram atropine sulfate and scopolamine hydrobromide. The coefficient of variation for injection reproducibility in less than 1%. The method has been applied to composite and individual tablet assays of scopolamine hydrobromide and atropine sulfate. The HPLC results are comparable (within 1%) to those obtained using the USP procedure; the HPLC method requires less sample preparation.