Rapid analysis of olanzapine and desmethylolanzapine in human plasma using high-performance liquid chromatography with coulometric detection

Determination of levofloxacin, norfloxacin, and moxifloxacin in pharmaceutical dosage form or individually using derivative UV spectrophotometry

PURPOSE

In this study, first, second, third, and fourth-order derivative spectrophotometric methods utilizing the peak-zero (P-O) and peak-peak (P-P) techniques of measurement were developed for the determination of levofloxacin, norfloxacin, and moxifloxacin. These methods were applied to their combined pharmaceutical dosage form or individually for levofloxacin, norfloxacin, and moxifloxacin.

METHODS

Linearity was established in the concentration range of 2-20 µg/mL. The procedures are simple, quick, and precise. The developed methods are sensitive, accurate, and cost-effective, demonstrating excellent correlation coefficients (R2 = 0.9998) and mean recovery values ranging from 99.20% to 100.08%, indicating a high level of precision.

RESULTS

The developed approach was effectively employed to determine the levofloxacin, norfloxacin, and moxifloxacin content in commercially available pharmaceutical dosages.

CONCLUSIONS

Statistical analysis and recovery tests confirmed the method's linearity and accuracy. The results suggest that this method can be utilized for routine analysis in both bulk and commercial formulations. The simplicity, accuracy, and cost-effectiveness of the developed methods make them valuable for pharmaceutical analysis.

Multiplexed therapeutic drug monitoring of antipsychotics in dried plasma spots by LC-MS/MS

In this work, a convenient method for the therapeutic monitoring of seven common antipsychotic drugs in "dried plasma spot" samples has been developed. It is based on the liquid chromatography tandem mass spectrometry technique, operating in multiple reaction monitoring mode, and a straightforward procedure for the simultaneous extraction of all antipsychotics in a single step, with high extraction yield. The method was fully validated with proper accuracy, precision, selectivity and sensitivity, for all the drugs. Limits of quantification were 0.12, 1.09, 1.46, 1.47, 5.70, 1.32, 1.33 µg/L for haloperidol, aripiprazole, olanzapine, quetiapine, clozapine, risperidone, and paliperidone, respectively. Accuracy, intra- and interday precision values were <10% for all drugs at all concentration levels examined. The method was tested in the analysis of 30 plasma samples from real patients for each drug. The proposed analytical approach, by combining practical and logistical advantages of microsampling with liquid chromatography tandem mass spectrometry analytical performance, could offer an ideal strategy for accurate and timely therapeutic drug monitoring of antipsychotic drugs in most clinical settings, even in remote centers and/or in out-patient settings, bringing so many potential improvements in psychiatric patient care.

Determination of Chlorpromazine, Haloperidol, Levomepromazine, Olanzapine, Risperidone, and Sulpiride in Human Plasma by Liquid Chromatography/Tandem Mass Spectrometry (LC-MS/MS)

Background and Objective

In this study, turbo-ion spray as an interface of tandem mass spectrometry (MS/MS) was performed for sensitive and accurate quantification of chlorpromazine, haloperidol, levomepromazine, olanzapine, risperidone, and sulpiride in plasma samples.

Methods

Separation was performed by gradient reversed phase high-performance liquid chromatography using a mobile phase containing ammonium formiate 2 mM, pH 2.7, and acetonitrile flowing through a Restek PFP Propyl C18 analytical column (50 mm×2.1 mm i.d.) with particle size of 5 µm, at a flow rate of 800 µL/min. Positive ion fragments were detected in multiple reaction monitoring (MRM) mode. Sample preparation was achieved by solid phase extraction (SPE) (Oasis HLB).

Results

Mean extraction recoveries ranged from 82.75% to 100.96%. The standard calibration curves showed an excellent linearity, covering subtherapeutic, therapeutic, and toxic ranges. Intraday and interday validation using quality control (QC) samples were performed. The inaccuracy and imprecision were below 12% at all concentration levels. The limits of detection (LOD) and quantification (LOQ) for all analytes were under therapeutic ranges for all tested analytes. Thus, the proposed method was sensitive enough for the detection and determination of subtherapeutic levels of these antipsychotics in plasma samples. No interference of endogenous or exogenous molecules was observed and no carryover effects were recorded.

Conclusion

According to the results, the proposed method is simple, specific, linear, accurate, and precise and can be applied for antipsychotic analysis in clinical routine. This method was applied for the determination of the tested antipsychotics in plasma samples taken from 71 individuals.

Determination of olanzapine and N-desmethyl-olanzapine in plasma using a reversed-phase HPLC coupled with coulochemical detection: correlation of olanzapine or N-desmethyl-olanzapine concentration with metabolic parameters

BACKGROUND

Olanzapine (OLZ) is one of the most prescribed atypical antipsychotic drugs but its use is associated with unfavorable metabolic abnormalities. N-desmethyl-olanzapine (DMO), one of the OLZ metabolites by CYP1A2, has been reported to have a normalizing action on metabolic abnormalities, but this remains unclear. Our aim was to explore the correlation between the concentrations of OLZ or DMO with various metabolic parameters in schizophrenic patients.

METHODS

The chromatographic analysis was carried out with a solvent delivery system coupled to a Coulochem III coulometric detector to determine OLZ and DMO simultaneously in OLZ-treated patients. The correlation between the concentration of OLZ or DMO and the metabolic parameters was analyzed by the Spearman rank order correlation method (r s).

PRINCIPAL FINDINGS

The established analytical method met proper standards for accuracy and reliability and the lower limitation of quantification for each injection of DMO or OLZ was 0.02 ng. The method was successfully used for the analysis of samples from nonsmoking patients (n = 48) treated with OLZ in the dosage range of 5-20 mg per day. There was no correlation between OLZ concentrations and tested metabolic parameters. DMO concentrations were negatively correlated with glucose (r s = -0.45) and DMO concentrations normalized by doses were also negatively correlated with insulin levels (r s = -0.39); however, there was a marginally positive correlation between DMO and homocysteine levels (r s = +0.38).

CONCLUSIONS

The observed negative correlations between levels of DMO and glucose or insulin suggest a metabolic normalization role for DMO regardless of its positive correlation with a known cardiovascular risk factor, homocysteine. Additional studies of the mechanisms underlying DMO's metabolic effects are warranted.

Disposable pipette extraction for the simultaneous determination of biperiden and three antipsychotic drugs in human urine by GC–nitrogen phosphorus detection

Background: Disposable pipette extraction with reversed-phase sorbent is proposed for the fast and simple GC determination of the antipsychotic drugs chlorpromazine, olanzapine, clozapine and biperiden – an anticholinergic drug – in human urine. The method was validated and successfully applied to postmortem urine samples. The analytical run was 11 min and lidocaine was used as the internal standard. Results: The developed method showed good linearity, over the range of 0.34 to 5 ng/µl, for all compounds. The within-day and between-day precision and accuracy assays revealed values ≤15%, while the recoveries ranged from 85 to 120%. LOD and LOQ ranged from 0.28 to 0.42 ng/µl and from 0.85 to 3.58 ng/µl, respectively. Conclusion: The developed method is a user-friendly technique, which is simple and fast.

Determination of olanzapine by spectrophotometry using permanganate

Two new spectrophotometric methods using permanganate as the oxidimetric reagent for the determination of olanzapine (OLP) were developed and validated as per the current ICH guidelines. The methods involved the addition of known excess of permanganate to OLP in either acid or alkaline medium followed by the determination of unreacted permanganate at 550 nm (method A) or bluish-green color of manganate at 610 nm (method B). The decrease in absorbance in method A or increase in absorbance in method B as a function of concentration of OLP was measured and related to OLP concentration. Under optimized conditions, Beer's law was obeyed over the ranges 2.0 to 20 and 1.0 to 10 μg mL-1 in method A and method B, respectively. The calculated molar absorptivity values were 1.34 x 10(4) and 2.54 x 10(4) l mol-1cm-1 for method A and method B respectively, and the respective Sandell sensitivities were 0.0233 and 0.0123 μg cm-2. The LOD and LOQ for method A were calculated to be 0.37 and 1.13 μg mL-1and the corresponding values for method B were 0.16 and 0.48 μg mL-1. Intermediate precision, expressed as RSD was in the range 0.51 to 2.66 %, and accuracy, expressed as relative error ranged from 0.79 to 2.24 %. The proposed methods were successfully applied to the assay of OLP in commercial tablets with mean percentage recoveries of 102 ±1.59 % (method A) and 101 ±1.53 % (method B). The accuracy and reliability of the methods were further confirmed by performing recovery tests via standard addition procedure.

Sensitive liquid chromatography/tandem mass spectrometry method for the simultaneous determination of olanzapine, risperidone, 9-hydroxyrisperidone, clozapine, haloperidol and ziprasidone in rat brain tissue

One prerequisite for therapeutic effects of psychiatric drugs is the ability to pass the blood brain barrier. Hence, it is important to know the concentration of antipsychotic drugs in brain tissue. In general, determinations of lipophilic compounds from lipophilic matricies such as the brain are a challenge. Here we have adapted a plasma assay for antipsychotics for the target organ the brain. Using modified sample preparation and chromatographic strategies, the analytes were extracted from rat brain homogenate and analyzed by LC-MS/MS. The method used a Waters Atlantis dC-18 (30 mm x 2.1 mm i.d., 3 microm) column with a mobile phase of acetonitrile/5 mM ammonium formate (pH 6.1 adjusted with formic acid) and gradient elution. All analytes were detected in positive ion mode using multiple-reaction monitoring. The method was validated and the linearity, lower limit of quantitation, precision, accuracy, recoveries, specificity and stability were determined. This method was then successfully used to quantify the rat brain tissue concentration of the analytes after chronic treatment with these antipsychotic drugs.

Simultaneous determination of five antipsychotic drugs in rat plasma by high performance liquid chromatography with ultraviolet detection

A significant percentage of psychiatric patients who are treated with antipsychotics are treated with more than one antipsychotic drug in the clinic. Thus, it is advantageous to use a rapid and reliable assay that is suitable for determination of multiple antipsychotic drugs in plasma in a single run. A simple and sensitive HPLC-UV method was developed and validated for simultaneous quantification of olanzapine, haloperidol, chlorpromazine, ziprasidone, risperidone and its active metabolite 9-hydroxyrisperidone in rat plasma using imipramine as an internal standard (I.S.). The analytes were extracted from rat plasma using a single step liquid-liquid acid solution back extraction technique with wash procedure, which provided the very clear baseline for blank plasma extraction. The compounds were separated on an Agilent Eclipse XDB C8 (150 mm x 4.6 mm i.d., 5 microm) column using a mobile phase of acetonitrile/30 mM ammonium acetate including 0.05% triethylamine (pH 5.86 adjusted with acetic acid) with gradient elution. All of the analytes were monitored using UV detection. The method was validated and the linearity, lower limit of quantitation (LLOQ), precision, accuracy, recoveries, selectivity and stability were determined. The LLOQ was 2.0 ng/ml and correlation coefficient (R(2)) values for the linear range of 2.0-500.0 ng/ml were 0.998 or greater for all the analytes. The precision and accuracy for intra-day and inter-day were better than 7.44%. The recovery was above 74.8% for all of the analytes. This validated method has been successfully used to quantify the plasma concentration of the analytes for pharmacological and toxicological studies following chronic treatment with antipsychotic drugs in the rat.

Liquid chromatography/tandem mass spectrometry method for the simultaneous determination of olanzapine, risperidone, 9-hydroxyrisperidone, clozapine, haloperidol and ziprasidone in rat plasma

A simple, sensitive and rapid liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) method was developed and validated for simultaneous quantification of olanzapine, clozapine, ziprasidone, haloperidol, risperidone, and its active metabolite 9-hydroxyrisperidone, in rat plasma using midazolam as internal standard (IS). The analytes were extracted from rat plasma using a single step liquid-liquid extraction technique. The compounds were separated on a Waters Atlantis dC-18 (30 mm x 2.1 mm i.d., 3 microm) column using a mobile phase of acetonitrile/5 mM ammonium formate (pH 6.1 adjusted with formic acid) with gradient elution. All of the analytes were detected in positive ion mode using multiple reaction monitoring (MRM). The method was validated and the specificity, linearity, lower limit of quantitation (LLOQ), precision, accuracy, recoveries and stability were determined. LLOQ was 0.1 ng/mL and correlation coefficient (R(2)) values for the linear range of 0.1-100 ng/mL were 0.997 or greater for all the analytes. The intra-day and inter-day precision and accuracy were better than 8.05%. The relative and absolute recovery was above 77% and matrix effects were low for all the analytes except for ziprasidone. This validated method has been successfully used to quantify the plasma concentration of the analytes after chronic treatment with antipsychotic drugs.

Determination of Olanzapine in rat brain using liquid chromatography with coulometric detection and a rapid solid-phase extraction procedure

A sensitive and selective method was developed for the determination of the antipsychotic drug Olanzapine levels in rat brain tissue, based on HPLC with electrochemical detection. The analyses were carried out on a C8 reversed phase column (150 mm x 4.6 mm, 5 microm), using a mobile phase composed of methanol and a phosphate buffer (44.0 mM, pH 3.5), containing triethylamine (21:79, v/v), flowing at 1.2 mL min(-1). A high sensitivity coulometric detection analytical cell containing two flow-through low volume working electrodes was used: electrode 1 was set at +0.350 V and electrode 2 at -0.200 V. Olanzapine, administered to rats in different doses or in different times, was extracted from tissue homogenate of either the whole brain or specific areas (cortex, hyppocampus, nucleus striatum) with a rapid solid phase extraction procedure (SPE) on Oasis HLB cartridges. The method provided a high extraction yield of Olanzapine and internal standard (2-methylolanzapine) from brain tissue homogenate with absolute recovery values higher than 90.0%. The detector response was linear over a concentration range of 0.2-100.0 ng mL(-1) of Olanzapine. The limit of quantification (LOQ) was 0.2 ng mL(-1). Precision results, expressed by the intra-day and the inter-day relative standard deviation values, were satisfactory, better than 4.6%. Accuracy was satisfactory as well. This method proved to be suitable for the analysis of Olanzapine in rat brain tissues and for the study of distribution and pharmacokinetics of Olanzapine in rat brain after a single treatment with the antipsychotic drug.