Quantitative determination of atracurium in human plasma using high-performance liquid chromatography

The authors have established a new method for extraction and determination of atracurium in human plasma that employs a reversed phase high-performance liquid chromatography (HPLC). This method made use of a fluorescent spectrophotometer at an excitation wavelength of 240 nm and an emission wavelength of 310 nm. The mobile phase was made of a phosphate buffer, distilled water and acetonitrile (20V : 30V : 50V). The analytical column used was a Little Champ C(18). In a Bond Elute C(18) extraction column, which had been prewashed with a phosphate buffer and a 50% methanol solution, atracurium was extracted from acidified plasma samples using a mixture of methanol and phosphate buffer. A standard curve was prepared by the internal standard method using metocurine. A high linear correlation between atracurium concentration and the ratio of the atracurium peak height to the metocurine peak height was observed (r = 0.9994). The lowest threshold for detection of atracurium was 15 ng/ml. When the plasma concentrations of atracurium were determined in 2 clinical cases, t(1/2Alpha) was 2.10 and 1.73 min and t(1/2Beta) was 15.57 and 21.57 min, respectively. These results indicate that this method of extraction and determination is appropriate for studying the pharmacokinetics of atracurium because it allows a high reproducibility, and provides an extremely accurate, simple and quick analysis.