Improved method for the quantification of aminoglutethimide in urine samples.

Due to an unknown mechanism aminoglutethimide (AG) in urine samples is partly present in a form in which it is not detected. Though most evident if samples had been stored at -20 degrees C (about 60% trapped), it also occurred in fresh urine samples (about 20% trapped). Heating the urine sample for 15 min at 100 degrees C liberated all AG.