Abstract
High performance liquid chromatographic methods for the individual determination of khellin, phenobarbitone and dipyrone in tablets are presented. The methods specify a reverse phase column: methanol + water (68 + 32) as mobile phase at a flow rate of 0.7 ml/min with detection at 254 nm for khellin, visgnagin and dipyrone; water + ammonia + methanol (94.5 + 0.5 + 5) as a mobile phase at a flow rate of 0.7 ml/min with detection at 240 nm for phenobarbitone. At sensitivity of 0.01 AUFS, linearity ranges were found to be 0.5-4 micrograms/ml for khellin, 2.5-12.5 micrograms/ml for dipyrone and 1-7 micrograms/ml for phenobarbitone and with relative standard deviations less than 2%. The mean percentage recoveries +/- SD of khellin, dipyrone and phenobarbitone added to tablets were found to be 101.0 +/- 0.65, 100.0 +/- 0.74 and 99.9 +/- 0.74, respectively. The system can detect 2% w/w visnagin in khellin.