Simultaneous Determination of Several Antalgic Drugs Based on Their Interactions with -Cyclodextrin by Capillary Zone Electrophoresis

The binding constants of beta-cyclodextrin (beta-CD) with antalgic drugs such as naproxen, ketoprofen, ibuprofen, acemetacin, and aspirin are determined by affinity capillary electrophoresis. Based on these interactions, a reliable method for the separation and simultaneous determinations of these compounds in the presence of 5.0 mM beta-CD in phosphate buffer solution is presented by capillary zone electrophoresis with UV detection at 214 nm for naproxen and 200 nm for the others. The linear ranges for naproxen, ketoprofen, ibuprofen, acemetacin, aspirin, and caffeine detections are from 2.0 to 800, 2.5 to 1000, 2.5 to 700, 2.5 to 700, 2.0 to 800, and 1.5 to 800 microg/mL, respectively. Their detection limits are 1.0, 0.5, 0.5, 1.5, 1.5, and 1.0 microg/mL at a signal to noise ratio of 3, respectively. This method has been successfully applied to the detections of these drugs in the pharmaceutical formulations (tablets or capsules) and urine samples.