A gas chromatographic mass spectrometric chemical ionization assay for haloperidol with selected ion monitoring

Selective determination of haloperidol in human serum: surface ionization mass spectrometry and gas chromatography with surface ionization detection

Surface ionization organic mass spectrometry (SIOMS) has been performed on the clinically important drug haloperidol using quadrupole mass spectrometry in which the thermal ion source has a rhenium oxide emitter. The surface ionization (SI) mass spectrum is presented, interpreted in a purely empirical way by means of evidence from previous investigations, and then compared to results from conventional electron impact (EI) ionization. An approach to detection of this drug in serum by gas chromatography (GC) with a surface ionization detector (SID) and GC-SIOMS is described. This approach demonstrates that (a) haloperidol is efficiently surface-ionized, giving a unique SI mass spectrum, (b) experimental results rationalize the combined sensitivity and selectivity of the GC-SID for the examined drug, (c) the detection limit for haloperidol in serum is 1.1 ng/ml (S/N = 3) by GC-SID (the coefficients of variation of the assay are generally low, i.e., below 8.5%) and (d) the GC-SIOMS coupling can be used for sensitive and selective detection of haloperidol in serum.

Simultaneous determination of plasma haloperidol and its metabolite reduced haloperidol by liquid chromatography with electrochemical detection. Plasma levels in schizophrenic patients treated with oral or intramuscular depot haloperidol

A simple and highly sensitive liquid chromatographic method with electrochemical detection for the simultaneous determination of haloperidol and its metabolite reduced haloperidol in human plasma has been developed. The sample preparation for the analysis involves a simple one-step extraction procedure with 10% methylene chloride in pentane. The compounds were separated on a cyano column maintained at a temperature of 40 degrees C and were detected electrochemically by a flow-through analytical cell kept at +0.95 V. The standard curve is linear over the range of 0.1 to 15 ng/ml and the lower limit of quantitation is 0.1 ng/ml for haloperidol and 0.25 ng/ml for reduced haloperidol which is equivalent to approximately 40 pg on column when 1 ml of plasma was used for the analysis. The lower limit of quantitation for reduced haloperidol can be extended to 0.1 ng/ml if 2 ml of plasma is used in the analysis. The coefficient of variation of the determination of plasma levels by this method over the standard curve concentration range was less than 10%. Commonly co-administered drugs and other neuroleptics used in conjunction with haloperidol did not interfere in the determination of either haloperidol or reduced haloperidol. This method has been successfully used for the determination of haloperidol and reduced haloperidol in plasma and their levels in patients treated with various doses oral haloperidol or intramuscular haloperidol decanoate are reported.

Sensitive electrochemical high-performance liquid chromatography assay for the simultaneous determination of haloperidol and reduced haloperidol

An electrochemical HPLC method for the simultaneous determination of haloperidol and reduced haloperidol in plasma is presented. Chlorohaloperidol serves as the internal standard. A cyanopropyl bond elut column was used for sample preparation. The eluate was evaporated and reconstituted with mobile phase and injected onto a nitrile bonded column. The chromatographic system consisted of an ESA Coulochem detector operated in the screen mode. Intra- and interassay coefficients of variation for both compounds were less than 7%, with a sensitivity limit of 20 pg on the column. A plasma level-time profile is presented to illustrate the sensitivity and applicability of this assay in small animal and human pharmacokinetic studies.

Positive- and negative-ion mass spectrometry of butyrophenones

Positive-ion electron-impact (EI), positive-ion chemical ionization (CI) and medium-pressure negative-ion CI mass spectra of ten butyrophenones are presented. Low-pressure (0.01 Torr) negative CI spectra are also presented for some compounds. In the positive EI mode, a peak at m/z 42, which corresponded to the propyl group, appeared for all compounds; a peak at m/z 123 was also common to all compounds except for the two with a bis(fluorophenyl) group. Molecular ions were generally very small or missing in the positive EI mode. In the positive CI mode, strong [M+H]+ quasi-molecular peaks generally appeared together with [M+C2H5]+ peaks; [M-F]+ peaks appeared in many compounds and [M-OH]+ peaks also appeared for compounds having a hydroxypiperidinyl group. In the negative CI mode with a 1 Torr chamber pressure, their spectra were generally simple with [M-H]- quasi-molecular ions; anions of liberated halogens were not observed except for bromine at this pressure. In the negative CI mode at low pressure (0.01 Torr), some fragment peaks in the lower mass range appeared in addition to the quasi-molecular ions; halogen peaks (m/z 19 or 35) and anions at m/z 95, which corresponded to the fluorophenyl group, appeared in most spectra recorded at this pressure. An procedure for the extraction of butyrophenones from human urine and plasma and their separation by gas chromatography was also developed to serve for their identification in forensic science practice.

Improved gas chromatographic-mass spectrometric assay for haloperidol utilizing ammonia chemical ionization and selected-ion monitoring

An improved method for the analysis of haloperidol in human serum, utilizing gas chromatography-ammonia chemical ionization mass spectrometry is described. A tetradeutero analogue of haloperidol is utilized as the internal standard, while a second drug, thioridazine, is added as a priming compound. The characteristic high sensitivity and selectivity of selected-ion monitoring combined with the added accuracy provided by incorporation of a labeled internal standard provide a reliable method for the quantitation of low levels of haloperidol.

Determination of benperidol in human plasma by high-performance liquid chromatography

A high-performance liquid chromatographic method for the quantitative determination of benperidol in human plasma using haloperidol as internal standard is described. The method involves liquid-liquid extraction, separation of the substances on a reversed-phase column C18 followed by ultraviolet detection at 254 nm. The mobile phase consists of 32% acetonitrile in 0.05 M potassium dihydrogen phosphate buffer (pH 2.8). The detection limit is 0.5-1.0 ng/ml using 2- or 4-ml plasma samples.