HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ASSAY FOR THE DETERMINATION OF HALOPERIDOL IN PLASMA

A sensitive, reproducible and accurate high performance liquid chromat ographic (HPLC) method for the quantitative determination of haloperid ol in plasma has been developed and validated. Sample preparation invo lves extraction of haloperidol and diazepam (internal standard) from 0 .5 mt plasma. The separation was carried out in a stainless steel, res olve C-18 column with a mobile phase composed of a mixture of 55% meth anol and 45% HPLC water containing 0.2 M ammonium acetate and adjusted to an apparent pH 7.2. The mobile phase was pumped at a flow rate of 1.5 mL/min. The column oven temperature was adjusted at 38 degrees C a nd the effluent was monitored at 249 nm. The retention times for the i nternal standard and haloperidol were found to be 5.1 and 6.3 minutes, respectively. Peak-height ratios of the drug to the internal standard were used for the quantification of haloperidol in the plasma samples . The average (+/-SD) absolute and relative recovery of haloperidol we re 97+/-3.6% and 100 6+/-1.52%, respectively. The intraday coefficient s of variation (CVs) ranged from 1.74 to 4.68%, while the interday CVs varied from 2.31 to 5.23%. The detection limit for haloperidol in pla sma was found to be 5 ng/mL.