Electromembrane extraction of chlorprothixene, haloperidol and risperidone from whole blood and urine.

Separation of antipsychotic drugs from whole blood and urine is of great importance for clinic and forensic laboratories. In this work, chlorprothixene, haloperidol and risperidone representing the first and second generations of antipsychotic drugs were studied. Among them, chlorprothixene and risperidone were investigated for the first time by electromembrane extraction (EME). After the screening, 2-nitrophenyl octyl ether (NPOE) was used as the supported liquid membrane (SLM). The EME performance for spiked water (pH 2), whole blood and urine was tested and optimized individually. Using NPOE and 60 V, efficient EME was achieved from urine and whole blood with trifluoroacetic acid as the acceptor solution. The equilibrium time required for EME was dependent on the sample matrices. The steady-state of EME was reached in 30 min and 20 min for whole blood and urine, respectively. At steady-state, the EME recoveries of the targets from different sample matrices were satisfactory, and were in the range of 74%-100%. The proposed EME approach combined with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was evaluated using whole blood and urine. The obtained linearity was 1-200 ng mL-1, and the coefficient of determination (R2) was ≥ 0.9853 for haloperidol and ≥ 0.9936 for chlorprothixene and risperidone. The limit of detection (LOD) and accuracy for all the targets ranged from 0.2-0.6 ng mL-1 and 102%-110%, respectively, and the repeatability at low (1 ng mL-1), medium (10 ng mL-1) and high (200 ng mL-1) concentration was ≤ 12% (RSD). Finally, the validated approach was successfully used to determine chlorprothixene, risperidone and haloperidol in whole blood and urine from rats, which were treated with chlorprothixene, risperidone and haloperidol at low therapeutic dose, respectively.

Dopamine D2 Receptor Occupancy Estimated From Plasma Concentrations of Four Different Antipsychotics and the Subjective Experience of Physical and Mental Well-Being in Schizophrenia: Results From the Randomized NeSSy Trial.

BACKGROUND: Impaired subjective well-being in schizophrenia patients treated with antipsychotics has often been linked inter alia to the antidopaminergic effects of medication. Thus, it is important to capture the association between striatal dopamine D2 receptor occupancy (D2-RO) and global subjective well-being. We examined this association using data from our multicenter, randomized, double-blind Neuroleptic Strategy Study (NeSSy). METHODS: An innovative double randomization process was used for allocation of patients to the specific treatment groups. Plasma drug concentrations were measured after 6 and 24 weeks of treatment to obtain the estimated D2-RO (eD2-RO) relative to literature values. We made an exploratory analysis of associations between eD2-RO and subjective well-being scores. One hundred two blood samples from 69 patients were available for the analysis. Because of the lack of a satisfactory occupancy model for quetiapine, only haloperidol, flupentixol, and olanzapine treatment groups were pooled, whereas aripiprazole data were analyzed separately, because of its partial agonistic properties. RESULTS: In the pooled antagonist group, eD2-RO correlated negatively with the summarized well-being score. In a more detailed analysis, this association could be confirmed for all first-generation antipsychotic-treated patients, but not for the separate second-generation antipsychotic groups. In the aripiprazole group, higher eD2-RO was associated with impaired physical well-being, but had no association with mental well-being. CONCLUSIONS: Our results suggest that high plasma levels and consequently high occupancy at D2 receptors are disadvantageous for subjective well-being, as distinct from the objective extrapyramidal side effects. To minimize patients' malaise, which disfavors adherence, implementation of therapeutic drug monitoring in the clinical routine may be useful.

Highly sensitive and selective method for the rapid determination and preconcentration of haloperidol by using a magnetite-molecularly imprinted polymer.

A sensitive and selective method based on the determination of haloperidol with the usage of magnetite-molecularly imprinted polymer and high-resolution liquid chromatography has been developed. This novel method is rapid as the detection procedure for haloperidol can be completed within a total time of 1 h. The same imprinted polymer can be used for the determination of haloperidol at least 20 times. The proposed method has been succesfully applied to synthetic urine and serum samples and the recoveries of the spiked samples were in the range of 94.7-100.7%. The limit of detection and limit of quantification of the method were 2.25 and 7.50 µg/L, respectively. Linearity of the calibration graph was observed within the range of 10-250 µg/L. By combining the high capacity, high selectivity, and reusability of the magnetic adsorbent with the dynamic calibration range, high sensitivity and high resolution of liquid chromatography with quadrupole time-of-flight mass spectrometry, the proposed method is an ideal method for the determination and preconcentration of trace levels of haloperidol. A magnetite-molecularly imprinted polymer has been used for the first time as a selective adsorbent for the determination of haloperidol.

Monitoring Haloperidol Plasma Concentration and Associated Adverse Events in Critically Ill Children With Delirium: First Results of a Clinical Protocol Aimed to Monitor Efficacy and Safety.

OBJECTIVES: As delirium in critically ill children is increasingly recognized, more children are treated with the antipsychotic drug haloperidol, while current dosing guidelines are lacking solid evidence and appear to be associated with a high risk of adverse events. We aim to report on the safety and efficacy of a recently implemented clinical dose-titration protocol with active monitoring of adverse events. DESIGN: From July 2014 until June 2015, when a potential delirium was identified by regular delirium scores and confirmed by a child psychiatrist, haloperidol was prescribed according to the Dutch Pediatric Formulary. Daily, adverse events were systematically assessed, haloperidol plasma concentrations were measured, and delirium symptoms followed. Dependent on the clinical response, plasma concentration, and adverse event, the dose was adjusted. SETTING: A 28-bed tertiary PICU in the Netherlands. PATIENTS: All patients admitted to the PICU diagnosed with delirium. INTERVENTION: Treatment with haloperidol according to a dose-titration protocol MEASUREMENTS AND MAIN RESULTS:: Thirteen children (median age [range] 8.3 yr [0.4-13.8 yr]) received haloperidol, predominantly IV (median dose [range] 0.027 mg/kg/d [0.005-0.085 mg/kg/d]). In all patients, pediatric delirium resolved, but five of 13 patients developed possible adverse event. These were reversed after biperiden (n = 2), discontinuing (n = 3), and/or lowering the dose (n = 3). Plasma concentrations were all below the presumed therapeutic threshold of 3-12 µg/L. CONCLUSIONS: Prospective systematic monitoring of adverse event in critically ill children receiving haloperidol revealed a significant proportion of possible adverse events. Adverse event developed despite low plasma concentrations and recommended dose administration in the majority of the patients. Our data suggest that haloperidol can potentially improve pediatric delirium, but it might also put patients at risk for developing adverse events.

An investigation of regional cerebral blood flow and tissue structure changes after acute administration of antipsychotics in healthy male volunteers.

Chronic administration of antipsychotic drugs has been linked to structural brain changes observed in patients with schizophrenia. Recent MRI studies have shown rapid changes in regional brain volume following just a single dose of these drugs. However, it is not clear if these changes represent real volume changes or are artefacts ("apparent" volume changes) due to drug-induced physiological changes, such as increased cerebral blood flow (CBF). To address this, we examined the effects of a single, clinical dose of three commonly prescribed antipsychotics on quantitative measures of T1 and regional blood flow of the healthy human brain. Males (n = 42) were randomly assigned to one of two parallel groups in a double-blind, placebo-controlled, randomized, three-period cross-over study design. One group received a single oral dose of either 0.5 or 2 mg of risperidone or placebo during each visit. The other received olanzapine (7.5 mg), haloperidol (3 mg), or placebo. MR measures of quantitative T1, CBF, and T1-weighted images were acquired at the estimated peak plasma concentration of the drug. All three drugs caused localized increases in striatal blood flow, although drug and region specific effects were also apparent. In contrast, all assessments of T1 and brain volume remained stable across sessions, even in those areas experiencing large changes in CBF. This illustrates that a single clinically relevant oral dose of an antipsychotic has no detectable acute effect on T1 in healthy volunteers. We further provide a methodology for applying quantitative imaging methods to assess the acute effects of other compounds on structural MRI metrics. Hum Brain Mapp 39:319-331, 2018. © 2017 Wiley Periodicals, Inc.

Rat brain CYP2D enzymatic metabolism alters acute and chronic haloperidol side-effects by different mechanisms.

Risk for side-effects after acute (e.g. parkinsonism) or chronic (e.g. tardive dyskinesia) treatment with antipsychotics, including haloperidol, varies substantially among people. CYP2D can metabolize many antipsychotics and variable brain CYP2D metabolism can influence local drug and metabolite levels sufficiently to alter behavioral responses. Here we investigated a role for brain CYP2D in acutely and chronically administered haloperidol levels and side-effects in a rat model. Rat brain, but not liver, CYP2D activity was irreversibly inhibited with intracerebral propranolol and/or induced by seven days of subcutaneous nicotine pre-treatment. The role of variable brain CYP2D was investigated in rat models of acute (catalepsy) and chronic (vacuous chewing movements, VCMs) haloperidol side-effects. Selective inhibition and induction of brain, but not liver, CYP2D decreased and increased catalepsy after acute haloperidol, respectively. Catalepsy correlated with brain, but not hepatic, CYP2D enzyme activity. Inhibition of brain CYP2D increased VCMs after chronic haloperidol; VCMs correlated with brain, but not hepatic, CYP2D activity, haloperidol levels and lipid peroxidation. Baseline measures, hepatic CYP2D activity and plasma haloperidol levels were unchanged by brain CYP2D manipulations. Variable rat brain CYP2D alters side-effects from acute and chronic haloperidol in opposite directions; catalepsy appears to be enhanced by a brain CYP2D-derived metabolite while the parent haloperidol likely causes VCMs. These data provide novel mechanistic evidence for brain CYP2D altering side-effects of haloperidol and other antipsychotics metabolized by CYP2D, suggesting that variation in human brain CYP2D may be a risk factor for antipsychotic side-effects.

Lipoic acid and haloperidol-induced vacuous chewing movements: Implications for prophylactic antioxidant use in tardive dyskinesia.

Tardive dyskinesia (TD), a potentially irreversible antipsychotic (AP)-related movement disorder, is a risk with all currently available antipsychotics. AP-induced vacuous chewing movements (VCMs) in rats, a preclinical model of TD, can be attenuated by antioxidant-based treatments although there is a shortage of well-designed studies. Lipoic acid (LA) represents a candidate antioxidant for the treatment of oxidative stress-related nervous system disorders; accordingly, its effects on AP-induced VCMs and striatal oxidative stress were examined. Rats treated with haloperidol decanoate (HAL; 21mg/kg every 3weeks, IM) for 12weeks were concurrently treated with LA (10 or 20mg/kg, PO). VCMs were assessed weekly by a blinded rater, and locomotor activity was evaluated as were striatal lipid peroxidation markers and serum HAL levels. VCMs were decreased by the lower dose (nonsignificant), whereas a significant increase was recorded with the higher dose of LA. HAL decreased locomotor activity and this was unaffected by LA. Striatal malondialdehyde (MDA) levels in HAL-treated rats were reduced by both LA doses, while 4-hydroxynonenal (4-HNE) levels were predictive of final VCM scores (averaged across weeks 10-12). Study limitations include differences between antipsychotics in terms of oxidative stress, LA dosing, choice of biomarkers for lipid peroxidation, and generalizability to TD in humans. Collectively, current preclinical evidence does not support a "protective" role for antioxidants in preventing TD or its progression, although clinical evidence offers limited evidence supporting such an approach.

Genotype and co-medication dependent CYP2D6 metabolic activity: effects on serum concentrations of aripiprazole, haloperidol, risperidone, paliperidone and zuclopenthixol.

PURPOSE: Therapeutic drug monitoring (TDM) of antipsychotics can aid in therapy optimization, explaining adverse effects or non-response. One reason for therapeutic failure or adverse effects is caused by genetic variations in the cytochrome P450 drug-metabolizing genes. The aim of this study was to evaluate the impact of CYP2D6 polymorphisms on steady-state serum concentrations of antipsychotics metabolized by CYP2D6, taking into account the co-medication with CYP2D6 inhibitors. METHODS: Serum and EDTA samples were collected from 82 psychiatric patients. After a liquid-liquid extraction, serum samples were analyzed using an ultra-high performance liquid chromatography-tandem mass spectrometric (UHPLC-MS/MS) method for quantification of the antipsychotics. CYP2D6 genotyping was performed using the Luminex xTAG® CYP2D6 Kit v3 (Luminex Corporation). Patients were divided into five phenotype subgroups by calculation of the activity score (AS): poor metabolizers (PM; AS 0), intermediate metabolizers (IM; AS 0.5-1), extensive metabolizers with slow activity (EM-s; AS 1-1.5), extensive metabolizers with fast activity (EM-f; AS 2), and ultra-rapid metabolizers (UM; AS >2). The influence of the phenotypes on the concentration-to-dose and metabolite-to-parent ratios was evaluated. RESULTS: Overall, 6.1 % UM (n = 5), 25.6 % EM-f (n = 21), 46.3 % EM-s (n = 38), 1.2 % EM-s/EM-f (n = 1), 6.1 % IM (n = 5), and 14.6 % PM (n = 12) were found, taking co-administration of strong and moderate CYP2D6 inhibitors into account (phenoconversion). It was demonstrated that CYP2D6 polymorphisms affect the serum concentrations of aripiprazole (n = 18), haloperidol (n = 11), risperidone (n = 20), and zuclopenthixol (n = 6), while no influence was seen on the paliperidone serum concentrations (n = 31). CONCLUSIONS: Even with a small number of patients per antipsychotic, the importance of CYP2D6 genotyping was still clearly stated. This study illustrates the high potential of combining TDM and CYP2D6 genotyping in clinical practice.

Quantitation of Haloperidol, Fluphenazine, Perphenazine, and Thiothixene in Serum or Plasma Using Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS).

Haloperidol, fluphenazine, perphenazine, and thiothixene are "typical" antipsychotic drugs that are used in the treatment of schizophrenia and other psychiatric disorders. The monitoring of the use of these drugs has applications in therapeutic drug monitoring and overdose situations. LC-MS/MS is used to analyze plasma/serum extracts with deuterated analog of imipramine as the internal standard to ensure accurate quantitation and control for any potential matrix effects. Positive ion electrospray is used to introduce the analytes into the mass spectrometer. Selected reaction monitoring of two product ions for each analyte allows for the calculation of ion ratios which ensures correct identification of each analyte, while a matrix-matched calibration curve is used for quantitation.

Nano-ropinirole for the management of Parkinsonism: blood-brain pharmacokinetics and carrier localization.

AIM: The aim of this study was to investigate the brain targeting potential of chitosan-coated oil in water nanoemulsions (CSNE(ROP)) delivered intranasally in haloperidol-induced Parkinson's disease rat models. METHODS: Chitosan-coated nanoemulsion (CSNE(ROP)) was developed through aqueous titration followed by a high pressure homogenization method. RESULTS: Gamma-scintigraphy study showed a significantly high mucoadhesive potential of CSNE(ROP) and least for conventional and homogenized formulations. Confocal study showed deep localization of formulations in the brain confirming the permeation potential of CSNE(ROP). Pharmacokinetic results of CSNE(ROP) in Wistar rat brain and plasma showed a significantly high (p** < 0.005) AUC0→24 and amplified Cmax over i.v treatment group. Neurobehavioral activity (rotarod and swim tests) and biochemical parameters (glutathion, TBARS and SOD) corroborated well with the pharmacokinetic results. The order of dopamine recovery in haloperidol-induced Wistar rats was found to be (i.n)CSNEROP group>(i.n)SolnROP group>(i.v)SolnROP group>haloperidol group. CONCLUSIONS: Finally, the investigation demonstrated that intranasal delivery of mucoadhesive nanocarrier might play as a potential candidate in the management of Parkinson's disease and related brain disorders.

The Influence of the CYP3A4*22 Polymorphism and CYP2D6 Polymorphisms on Serum Concentrations of Aripiprazole, Haloperidol, Pimozide, and Risperidone in Psychiatric Patients.

INTRODUCTION: Cytochrome P450 3A4 (CYP3A4) is involved in the metabolism of greater than 50% of the prescribed drugs. Recently, the CYP3A4*22 allele was reported to be associated with lower CYP3A4 expression and activity. Quetiapine, an antipsychotic metabolized by only CYP3A4, displayed higher serum levels in CYP3A4*22 carriers. Aripiprazole, haloperidol, pimozide, and risperidone are antipsychotics that are metabolized by CYP3A4 and CYP2D6. We investigated to which degree the CYP3A4*22 single-nucleotide polymorphism affects serum concentrations of patients receiving these drugs and compared this with the influence of CYP2D6 polymorphisms. METHODS: Eight hundred thirty-four adult patients were included in this study, of whom 130 used aripiprazole, 312 used haloperidol, 86 used pimozide, and 396 used risperidone. Serum levels of the drug and, if available, their active metabolites were collected as well as information on dose. Patients were genotyped for CYP3A4*22 using restriction fragment length polymorphism analysis. Genotyping for CYP2D6 was done with allele-specific polymerase chain reaction. RESULTS: No differences were found in serum (dose-corrected) concentrations of the antipsychotics between CYP3A4*22 wild-type and carrier groups. In contrast, CYP2D6 genotype did affect dose-corrected concentrations of the antipsychotics: for example, median dose-corrected concentrations were 56%, 86%, and 400% higher in predicted poor metabolizers versus extensive metabolizers for aripiprazole (P = 0.004), haloperidol (P > 0.001), and risperidone (P < 0.001), respectively, although a multiple regression analysis showed that only 4% to 17% of the variation in these concentrations could be explained by CYP2D6 status. CONCLUSIONS: Heterozygous presence of CYP3A4*22 does not increase serum levels of antipsychotics metabolized by both CYP3A4 and CYP2D6, whereas CYP2D6 polymorphisms do affect serum levels to a limited extent.

[Plasma levels of antipsychotics and the severity of side-effects in the treatment of schizophrenia exacerbation].

OBJECTIVE: To study a relationship between plasma levels of antipsychotics (AP) and severity of side-effects (SE) during the treatment of inpatients with exacerbation of schizophrenia. MATERIAL AND METHODS: The study included 39 patients treated with risperidone, haloperidol, zuclopenthixol, clozapine, aripiprazole or olanzapine as monotherapy or in combination of two AP. Blood sampling to measure the AP plasma level was performed twice (at 7-10 and 26-30 day from start of treatment), the levels of prolactin and glucose were determined once (at 26-30 day from start of treatment). Patients were assessed by psychometric scales PANSS and NSA and the side-effects scale UKU. RESULTS: The increased concentration of AP was noted in 33% of the patients. The high concentration of AP was significantly associated with akathisia and hyperkinesia (by UKU scale), NSA retardation factor and hyperprolactinemia. Patients with severe hyperprolactinemia were twice as likely to have a clinically significant depression. Increased blood glucose levels were observed in 18% of the patients, there was no significant association with AP plasma levels. Mental SE were most prominent, with a drift towards the neurological SE in the group with higher AP plasma levels. Chlorpromazine equivalent didn't significantly differ in the groups with normal, high and low AP concentrations. CONCLUSION: Elevated AP plasma levels, which were associated with some clinically significant SE and some negative symptoms, were found in most patients. In this regard, therapeutic drug monitoring is a promising method for the individualization of schizophrenia exacerbation treatment in routine clinical practice.

A rational approach to employing high plasma levels of antipsychotics for violence associated with schizophrenia: case vignettes.

Forensic psychiatric settings contain a high prevalence of treatment-resistant violent schizophrenia patients. Clozapine therapy has the most robust data for the management of violence in patients with schizophrenia, but for those who cannot tolerate or refuse clozapine, high-dose antipsychotic treatment to high achieve high plasma levels remains a viable option despite limited evidence for efficacy in controlled trials. This article enumerates rational guidelines for employing high plasma level strategies, emphasizing the appropriate interpretation of, and reaction to high plasma antipsychotic levels in these treatment resistant patients, and the need to push treatment to the limits of tolerability or clinical response.

Lack of correlation between the steady-state plasma concentrations of aripiprazole and haloperidol in Japanese patients with schizophrenia.

BACKGROUND: Both aripiprazole and haloperidol have been used in the treatment of schizophrenia, and are metabolized by the cytochrome P450 (CYP) 2D6 and CYP3A4. The authors studied the correlations between the steady-state plasma concentrations (Css) of aripiprazole and its active metabolite, dehydroaripiprazole, and those of haloperidol in 19 Japanese patients with schizophrenia, together with the effects of CYP2D6 genotypes on the steady-state kinetics of these compounds. METHODS: All the patients received first 24 mg/d of aripiprazole for 3 weeks and later received 6 mg/d of haloperidol for 2 weeks. Blood samplings were performed at least 2 weeks after the initiation of each treatment. The Css values of aripiprazole and dehydroaripiprazole were measured using liquid chromatography with mass spectrometric detection, and those of haloperidol were measured by using an enzyme immunoassay. CYP2D6 genotypes were determined by using polymerase chain reaction analysis. RESULTS: None of the correlations between the Css of aripiprazole (r = 0.286) or the sum of aripiprazole plus dehydroaripiprazole (r = 0.344) and those of haloperidol were significant. The mean Css of aripiprazole was significantly higher (P < 0.05) in the subjects with 1 *10 allele of CYP2D6 (n = 6) than in those with no mutated alleles (n = 13), whereas there were no significant differences in those of haloperidol between the 2 groups. CONCLUSIONS: This study suggests that the Css of aripiprazole and that of aripiprazole plus dehydroaripiprazole do not correlate with that of haloperidol in the same individual, because of the greater involvement of CYP2D6 in the metabolism of aripiprazole than in that of haloperidol.

Facile stripping voltammetric determination of haloperidol using a high performance magnetite/carbon nanotube paste electrode in pharmaceutical and biological samples.

Multi-walled carbon nanotubes decorated with Fe3O4 nanoparticles were prepared to construct a novel sensor for the determination of haloperidol (Hp) by voltammetric methods. The morphology and properties of electrode surface were characterized by scanning electron microscopy (SEM) and electrochemical impedance spectroscopy. This modified sensor was used as a selective electrochemical sensor for the determination of trace amounts of Hp. The peak currents of differential pulse and square wave voltammograms of Hp increased linearly with its concentration in the ranges of 1.2×10(-3)-0.52 and 6.5×10(-4)-0.52µmol L(-1), respectively. The detection limits for Hp were 7.02×10(-4) and 1.33×10(-4)µmol L(-1) for differential pulse and square wave voltammetric methods, respectively. The results show that the combination of multi-walled carbon nanotubes and Fe3O4 nanoparticles causes a dramatic enhancement in the sensitivity of Hp quantification. This sensor was successfully applied to determine Hp in pharmaceutical samples and biological fluids. The fabricated electrode showed excellent reproducibility, repeatability and stability.

HDAC inhibitors restore the capacity of aged mice to respond to haloperidol through modulation of histone acetylation.

Antipsychotic drugs are widely prescribed to elderly patients for the treatment of a variety of psychopathological conditions, including psychosis and the behavioral disturbances associated with dementia. However, clinical experience suggests that these drugs may be less efficacious in the elderly individuals than in the young. Recent studies suggest that aging may be associated with epigenetic changes and that valproic acid (VPA), a histone deacetylase inhibitor, may reverse such changes. However, it is not yet known whether HDAC inhibitors can modulate age-related epigenetic changes that may impact antipsychotic drug action. In this study, we analyzed conditioned avoidance response (CAR) and c-Fos expression patterns to elucidate the effect of HDAC inhibitors VPA and entinostat (MS-275) on behavioral and molecular markers of the effects of haloperidol (HAL) in aged mice. Our results showed that HAL administration failed to suppress the avoidance response during the CAR test, suggesting an age-related decrease in drug efficacy. In addition, HAL-induced c-Fos expression in the nucleus accumbens shell and prefrontal cortex was significantly lower in aged mice as compared with young mice. Pretreatment with VPA and MS-275 significantly improved HAL effects on the CAR test in aged mice. Also, VPA and MS-275 pretreatment restored HAL-induced increases in c-Fos expression in the nucleus accumbens shell and prefrontal cortex of aged mice to levels comparable with those observed in young mice. Lastly, but most importantly, increases in c-Fos expression and HAL efficacy in the CAR test of the HAL+VPA and HAL+MS-275 groups were correlated with elevated histone acetylation at the c-fos promoter region in aged mice. These findings suggest that pretreatment with VPA or MS-275 increases the behavioral and molecular effects of HAL in aged mice and that these effects occur via modulation of age-related histone hypoacetylation in the nucleus accumbens shell and prefrontal cortex.

Genetics of adverse reactions to haloperidol in a mouse diallel: a drug-placebo experiment and Bayesian causal analysis.

Haloperidol is an efficacious antipsychotic drug that has serious, unpredictable motor side effects that limit its utility and cause noncompliance in many patients. Using a drug-placebo diallel of the eight founder strains of the Collaborative Cross and their F1 hybrids, we characterized aggregate effects of genetics, sex, parent of origin, and their combinations on haloperidol response. Treating matched pairs of both sexes with drug or placebo, we measured changes in the following: open field activity, inclined screen rigidity, orofacial movements, prepulse inhibition of the acoustic startle response, plasma and brain drug level measurements, and body weight. To understand the genetic architecture of haloperidol response we introduce new statistical methodology linking heritable variation with causal effect of drug treatment. Our new estimators, "difference of models" and "multiple-impute matched pairs", are motivated by the Neyman-Rubin potential outcomes framework and extend our existing Bayesian hierarchical model for the diallel (Lenarcic et al. 2012). Drug-induced rigidity after chronic treatment was affected by mainly additive genetics and parent-of-origin effects (accounting for 28% and 14.8% of the variance), with NZO/HILtJ and 129S1/SvlmJ contributions tending to increase this side effect. Locomotor activity after acute treatment, by contrast, was more affected by strain-specific inbreeding (12.8%). In addition to drug response phenotypes, we examined diallel effects on behavior before treatment and found not only effects of additive genetics (10.2-53.2%) but also strong effects of epistasis (10.64-25.2%). In particular: prepulse inhibition showed additivity and epistasis in about equal proportions (26.1% and 23.7%); there was evidence of nonreciprocal epistasis in pretreatment activity and rigidity; and we estimated a range of effects on body weight that replicate those found in our previous work. Our results provide the first quantitative description of the genetic architecture of haloperidol response in mice and indicate that additive, dominance-like inbreeding and parent-of-origin effects contribute strongly to treatment effect heterogeneity for this drug.

Monitoring haloperidol exposure in body fluids and hair of children by liquid chromatography-high-resolution mass spectrometry.

BACKGROUND: Haloperidol, 4-[4-(4-chlorophenyl)-4-hydroxy-1-piperidinyl]-1-(4-fluorophenyl)-1-butanone (HP), one of the most widely used antipsychotics in the treatment of schizophrenia, mania, and other psychiatric disorders, is frequently encountered in cases of unintentional pediatric intoxication because the ingestion of a small amount can cause significant toxic effects in children. For monitoring HP in suspected ingestions, a liquid chromatography-high-resolution mass spectrometry method has been developed and validated in urine, blood, and hair samples. METHODS: The analyte was extracted from 1 mL blood or urine by liquid/liquid extraction and from 5 mg of hair by micropulverized extraction; gradient elution on an Atlantis T3 column was realized using HP-d4 as an internal standard. Positive ion electrospray ionization and high-resolution mass spectrometry determination were performed in an Orbitrap mass spectrometer. RESULTS: The method exhibited a r > 0.999 in the studied ranges (0.1-50 ng/mL in urine and blood and 0.1-50 ng/mg in hair) and a limit of quantification of 0.1 ng/mL for urine and blood and 0.1 ng/mg for hair; intra-assay and interassay relative SDs were always more than 18%. The method was applied to determine haloperidol in 3 children who were admitted to emergency departments. HP concentrations ranged from 2 to 21 ng/mL in urine, from not detected to 4.9 ng/mL in blood, and from 0.37 to 0.73 ng/mg in hair samples. CONCLUSIONS: The utilization of high-resolution/high-accuracy mass spectrometry in full scan mode allowed the identification of HP metabolites in urine and blood, thus unequivocally documenting the exposure to the drug. HP metabolites were structurally characterized by high-resolution multiple mass spectrometry. For the first time, a HP metabolite was detected in hair.

Determination of haloperidol in biological samples using molecular imprinted polymer nanoparticles followed by HPLC-DAD detection.

In this study an extraction procedure using molecular imprinted polymer nanoparticles for the determination of haloperidol in biological samples is proposed. The haloperidol imprinted polymer nanoparticles were synthesized successfully by precipitation polymerization in a flask containing haloperidol as a template, ethyleneglycoldimethacrylate as a crosslinking agent, methacrylic acid as a functional monomer, and 2,2'-azobisisobutyronitrile as an initiator. The leached and unleached polymer nanoparticles have been characterized by infrared spectroscopy and scanning electron microscopy. The effect of different variables such as the pH of solution, uptake and elution time, type, and the least amount of eluent for elution of haloperidol from polymer was evaluated. Extraction efficiencies more than 97% were obtained by elution of the polymer with 1.5 mL of methanol-acetic acid-trifluoroacetic acid 79.9:20:0.1. Under optimal conditions maximum adsorption capacity was obtained 153.84 mg g(-1). The detection limit of the proposed procedure was between 0.2 and 0.35 µg L(-1). Finally this method was applied to the determination of haloperidol in plasma and urine samples and satisfactory results were achieved (RSD<6.9%).