Naoko Suzuki

Quantitation of counter ion of a water-insoluble drug by nonaqueous capillary electrophoresis with indirect UV detection

This is a report on a capillary electrophoretic approach for the quantitation of the counter ions of drugs that are insoluble or slightly soluble in water. Using a nonaqueous run buffer, the sample solvents were not restricted, which is not the case with conventional aqueous run buffer systems. The separation selectivity could be manipulated using mixed solvents such as methanol and dimethylformamide as run buffers. Detection was carried out by indirect UV detection with phthalate. The linearity and the repeatability of the peak area of chloride was satisfactory. This approach was applied to the drug substance, azelastine hydrochloride, which is slightly soluble in water, and provided a value of chloride content consistent with the theoretical value.