Separation of olanzapine, carbamazepine and their main metabolites by capillary electrophoresis with pseudo-stationary phases

Integrated spectroscopic approaches for the facile one pot quantification of olanzapine in pharmaceutical formulation and spiked human plasma

In this work, the xanthene dye, erythrosine B, was employed as a probe for the determination of olanzapine using two fast and highly simple analytical approaches. The assay was based on the formation of a binary complex between the drug and erythrosine B in a slightly acidic aqueous buffered solution. In the first method, the absorbance of the formed product was monitored at 558 nm. The reaction stoichiometry was investigated, and the stability constant of the formed complex was estimated. The linear range of the method that obeyed Beer's law was in the concentration range of 0.6-8.0 µg/ml. The calculated detection and quantitation limits were 0.2 and 0.6 µg/mL. Upon adding the drug solution to erythrosine B, the native fluorescence of the dye was quenched and monitored at 550 nm after excitation at 528 nm. Thus, the fluorescence quenching was utilized as the quantitative signal in the spectrofluorimetric approach. The extent of quenching in the fluorescence intensity was rectilinear with the drug concentration in a range of 0.1-2.5 µg/ml with a detection limit of 0.032 µg/ml. Both approaches were analytically validated based on the guiding rules of the ICH with acceptable results, and were utilized efficiently in the analysis of olanzapine in commercial tablets containing the cited drug. In addition, owing to its high sensitivity and selectivity, the spectrofluorimetric method was applied for drug analysis in spiked human plasma with satisfactory % recoveries. Finally, the greenness of the methods was confirmed using eco-score scale and Analytical Green Evaluation metrics.

Carbamazepine

This chapter includes the aspects of carbamazepine. The drug is synthesized by the use of 5H-dibenz[b,f]azepine and phosgene followed by subsequent reaction with ammonia. Carbamazepine is generally used for the treatment of seizure disorders and neuropathic pain, it is also important as off-label for a second-line treatment for bipolar disorder and in combination with an antipsychotic in some cases of schizophrenia when treatment with a conventional antipsychotic alone has failed. Other uses may include attention deficit hyperactivity disorder, schizophrenia, phantom limb syndrome, complex regional pain syndrome, borderline personality disorder, and posttraumatic stress disorder. The chapter discusses the drug metabolism and pharmacokinetics and presents various methods of analysis of this drug such electrochemical analysis, spectroscopic analysis, and chromatographic techniques of separation. It also discusses its physical properties such as solubility characteristics, X-ray powder diffraction pattern, and thermal methods of analysis. The chapter is concluded with a discussion on its biological properties such as activity, toxicity, and safety.

Quantitative bioanalytical and analytical method development of dibenzazepine derivative, carbamazepine: A review

Bioanalytical methods are widely used for quantitative estimation of drugs and their metabolites in physiological matrices. These methods could be applied to studies in areas of human clinical pharmacology and toxicology. The major bioanalytical services are method development, method validation and sample analysis (method application). Various methods such as GC, LC-MS/MS, HPLC, HPTLC, micellar electrokinetic chromatography, and UFLC have been used in laboratories for the qualitative and quantitative analysis of carbamazepine in biological samples throughout all phases of clinical research and quality control. The article incorporates various reported methods developed to help analysts in choosing crucial parameters for new method development of carbamazepine and its derivatives and also enumerates metabolites, and impurities reported so far.

Electrochemical studies for the determination of quetiapine fumarate and olanzapine antipsychotic drugs

PURPOSE

Cyclic voltammetry and differential pulse voltammetry were used to explore the diffusion behavior of two antipsychotic drugs at a glassy carbon electrode. A well-defined oxidation peak was obtained in Britton-Robinson (BR) buffer (pH 2.0). The response was evaluated as a function of some variables such as the scan rate, and pH.

METHODS

A simple, precise, inexpensive and sensitive voltammetric method has been developed for the determination of the cited drugs Olanzapine (OLZ) and Quetiapine fumarate (QUT).

RESULTS

A linear calibration was obtained from 3 × 10(-8) M to 4 × 10(-6) M and 2 × 10(-8) M to 5 × 10(-6) M, with R. S. D. were 1.6 % and 1.2 % for OLZ and QUT, respectively. The limit of detection (LOD) was 1 × 10(-8) M, while the limit of quantification (LOQ) was 3 × 10(-8) M.

CONCLUSION

The method was applied to the determination of investigated drugs in urine and serum samples and dosage forms.

Cationic and perfluorinated polymeric pseudostationary phases for electrokinetic chromatography

Separation selectivity in electrokinetic chromatography (EKC) is directly affected by the chemistry and solvent characteristics of the pseudostationary phase (PSP). The chemical selectivity of micellar PSPs has been previously demonstrated to vary significantly between anionic and cationic surfactants as well as between hydrocarbon and fluorocarbon surfactants. Polymeric PSPs have also been demonstrated to provide unique selectivity. In the current study, four cationic polymeric pseudo-stationary phases, two of which have perfluorinated pendant groups, are introduced and characterized as PSPs in EKC. Their performance and selectivity is compared to conventional micellar PSPs with similar structure. The solvation characteristics and selectivity of the four polymers most closely resemble those observed for cationic micelles. The polymers are all more cohesive and more polar than their hydrocarbon micellar counterparts. The fluorocarbon PSPs did show preferential interaction with fluorocarbon solutes, were somewhat more cohesive, and were stronger hydrogen bond donors. However, the presence of fluorocarbon moieties did not have as dramatic an effect on selectivity as was observed and published previously for fluorocarbon micelles. This may result from the selectivity being dominated by the presence of the cationic head groups or from the fluorocarbon character of the pendant groups being moderated by the presence of hydrocarbon functionality on the polymer backbones.

Liquid chromatography/tandem mass spectrometry for the determination of carbamazepine and its main metabolite in rat plasma utilizing an automated blood sampling system

A liquid chromatography/tandem mass spectrometry (LC/MS/MS) method for the simultaneous determination of carbamazepine and its main metabolite carbamazepine 10,11-epoxide in rat plasma is described. The method consists of a liquid-liquid extraction procedure and electrospray LC/MS/MS analysis. The chromatographic separation was achieved within 5 min using a C(8) (150 mm x 2.1mm) 5 microm column with a mobile phase composed of water/acetonitrile/acetic acid (69.5:30:0.5, v/v/v) at a flow rate of 0.4 ml/min. D(10)-carbamazepine is used as the internal standard for all compounds. Analytes were determined by electrospray ionization tandem mass spectrometry in the positive ion mode using selected reaction monitoring (SRM). Carbamazepine was monitored by scanning m/z 237-->194, carbamazepine 10,11-epoxide by m/z 253-->210 and d(10)-carbamazepine by m/z 247-->204. The lower limit of quantitation (LLOQ) is 5 ng/ml for each analyte, based on 0.1 ml aliquots of rat plasma. The extraction recovery of analytes from rat plasma was over 87%. Intra-day and inter-day assay coefficients of variations were in the range of 2.6-9.5 and 4.0-9.6%, respectively. Linearity is observed over the range of 5-2000 ng/ml. This method was used for pharmacokinetic studies of carbamazepine and carbamazepine 10,11-epoxide in response to two different blood sampling techniques (i.e., manual sampling versus automated sampling) in the rat. Several differences between the two sampling techniques suggest that the method of blood collection needs to be considered in the evaluation of pharmacokinetic data.

Developments in the use of soluble ionic polymers as pseudo-stationary phases for electrokinetic chromatography and stationary phases for electrochromatography

This article reviews the development, characterization and application of soluble ionic polymeric materials as pseudo-stationary phases for electrokinetic chromatography and as stationary phases for electrochromatography since 1997. Polymeric pseudo-stationary phases for electrokinetic chromatography, including cationic polymers, anionic siloxane and acrylamide polymers, polymerized surfactants (micelle polymers), and chiral polymers are reviewed. Also reviewed are suspended molecularly imprinted polymer micro-particles. Application of polymeric pseudo-stationary phases with electrospray ionization mass spectrometric detection is presented. Recent progress in the development and characterization of physically adsorbed stationary phases for electrochromatography using polymers of the same or similar chemistry is also reviewed.

Analysis of antiepileptic drugs in biological fluids by means of electrokinetic chromatography

An overview of the electrokinetic chromatographic methods for the analysis of antiepileptic drug levels in biological samples is presented. In particular, micellar electrokinetic capillary chromatography is a very suitable method for the determination of these drugs, because it allows a rapid, selective, and accurate analysis. In addition to the electrokinetic chromatographic studies on the determination of antiepileptic drugs, some information regarding sample pretreatment will also be reported: this is a critical step when the analysis of biological fluids is concerned. The electrokinetic chromatographic methods for the determination of recent antiepileptic drugs (e.g., lamotrigine, levetiracetam) and classical anticonvulsants (e.g., carbamazepine, phenytoin, ethosuximide, valproic acid) will be discussed in depth, and their pharmacological profiles will be briefly described as well.

Optimization and validation of a capillary zone electrophoretic method for the simultaneous analysis of four atypical antipsychotics

A capillary zone electrophoretic method has been developed and optimized for separation of four atypical antipsychotics (AAPs): clothiapine (cT), clozapine (cZ), olanzapine (O), and quetiapine (Q). A three-level full-factorial design was applied to study the effect of the pH and molarity of the running buffer on separation. Combination of the studied parameters permitted the separation of the four AAPs, which was best carried out using 80 mM sodium phosphate buffer (pH 3.5). The same system can also be applied for the quantitative determination of these compounds. The method was then validated regarding linearity, precision, and accuracy. Especially, the possibility of simultaneous quantification and identification of the active ingredient in the finished product is very attractive.

Determination of carbamazepine by chemiluminescence detection using chemically prepared tris(2,2'-bipyridine)ruthenium(III) as oxidant

A new chemiluminescence method for the determination of carbamazepine (CBZ) has been developed. The method is based on the chemiluminescence produced in the reaction of tris(2,2'-bipyridine)ruthenium(III) and CBZ in an acidic medium. The chemiluminescence intensity was enhanced by organic solvents in the reaction system. Under the optimum experimental conditions, the calibration curve was linear over the range 4.0 x 10(-3)-8.6 x 10(-7) mol/L for CBZ. The detection limit (S/N = 3) was 2.5 x 10(-7) mol/L and the relative standard deviation of six replicate measurements was 2.6% for 4.0 x 10(-4) mol/L of CBZ. The possible reaction mechanism were also discussed. The chemiluminescence method was successfully applied to assay the CBZ contents in pharmaceutical tablets.

Modelling and optimization of the electrokinetic chromatographic separation of mixtures of organic anions and cations using poly(diallydimethyl- ammonium chloride) and hexanesulfonate as mixed pseudostationary phases

The separation of a series of aromatic carboxylic acids, sulfonates and opiates using electrokinetic chromatography employing a mixture of the soluble cationic polymer poly(diallydimethylammonium chloride) (PDDAC) and the amphiphilic anion hexanesulfonate as pseudostationary phases is described. In this system, the PDDAC pseudostationary phase interacts with the anionic analytes, whereas the hexanesulfonate pseudostationary phase interacts with the cationic analytes. A migration model has been derived which takes into account the ion-exchange (IE) interactions between the anions and the cationic PDDAC as well as the ion-pair (IP) interactions between the opiates and the hexanesulfonate. A further interaction between the combined PDDAC-hexanesulfonate complex and the more hydrophobic analytes is also evident and is accounted for in the model. Constants obtained by applying the model agreed well with the expected trends in IE affinities of the anions for PDDAC and also corresponded with the hydrophobic natures of the analytes. Optimization of the PDDAC and hexanesulfonate concentrations was performed using the normalized resolution product and minimum resolution product criteria. The minimum resolution product criterion proved to be most successful. An advantage of the described system is the improvement in peak shapes obtained after addition of hexanesulfonate to the electrolyte, resulting in increased plate numbers and better resolution. The system was very robust with mobilities varying by less than 2% over a period of days and on using different capillaries.

Octakis-6-sulfato-gamma-cyclodextrin as additive for capillary electrokinetic chromatography of dibenzoazepines: carbamazepine, oxcarbamazepine and their metabolites

Single isomer octakis-(2,3-dihydroxy-)6-sulfato-gamma-cyclodextrin used as pseudostationary phase of the background electrolyte interacts with dibenzo[b,f]azepines (consisting of a condensed 3-ring system) and forms negatively charged complexes. Hydroxygroups in position 2 and 3 at carbamazepine increase the extent of interaction, whereas substitution by oxygen at position 10 and/or 11 reduces it. The complex constants for the analytes are ranging from few tens L/mol (10-hydroxycarbamazepine, 10,11-dihydroxycarbamazepine, 10,11-epoxycarbamazepine, oxcarbazepine) to several hundreds L/mol (carbamazepine, 2-hydroxycarbamazepine, 3-hydroxycarbamazepine), and are much larger than those of the analytes with octakis-(2,3-dimethyl-)-6-sulfato-gamma-cyclodextrin. Full enantiomeric separation of the chiral metabolites of carbamazepine and oxcarbazepine is obtained at octakis-(2,3-dihydroxy-)-6-sulfato-gamma-cyclodextrin concentrations of about 10 mM (3 mM borate buffer, pH 8.5). Compared to heptakis-6-sulfato-beta-cyclodextrin, selectivity differs and stereoselectivity is more pronounced.

Simultaneous high-performance liquid chromatography determination of carbamazepine and five of its metabolites in plasma of epileptic patients

A high-performance liquid chromatographic method with UV detection for the simultaneous analysis of the antiepileptic drug carbamazepine and five of its metabolites in human plasma has been developed. The analysis was carried out on a reversed-phase column (C8, 150x4.6 mm I.D., 5 microm) using acetonitrile, methanol and a pH 1.9 phosphate buffer as the mobile phase. Under these chromatographic conditions, carbamazepine and its metabolites 10,11-dihydro-10,11-epoxycarbamazepine, 10,11-dihydro-10,11-dihydroxycarbamazepine, 2-hydroxycarbamazepine, 3-hydroxycarbamazepine and 10,11-dihydro-10-hydroxycarbamazepine are baseline separated in less than 18 min. The extraction of the analytes from plasma samples was performed by means of an original solid-phase extraction procedure using Oasis HLB cartridges. The method requires only 250 microl of plasma for one complete analysis. The repeatability (RSD%<2.4), intermediate precision (RSD%<3.5) and extraction yield (84.8-103.0%) were very good for all analytes. The method is suitable for reliable therapeutic drug monitoring of patients undergoing chronic treatment with carbamazepine and for kinetic-metabolic studies of this drug.