A rapid LC method for the identification and determination of CNS drugs in pharmaceutical formulations

UPLC-Tandem Mass Spectrometry Method for Simultaneous Determination of Fluoxetine, Risperidone, and Its Active Metabolite 9-Hydroxyrisperidone in Plasma: Application to Pharmacokinetics Study in Rats

Risperidone (RIS) is used as an antipsychotic drug alone or with other drugs, like fluoxetine (FLX). A simple method was developed and validated for the determination of both RIS and its metabolite 9-hydroxyrisperidone (9-OH-RIS), FLX, and olanzapine (OLA) as an internal standard in rat's plasma using UPLC-MS/MS. FLX, RIS, 9-OH-RIS, and OLA were purified using acetonitrile as a protein precipitating agent. Separation was performed on an ACQUITY™ "UPLC BEH™" C18 column (50 mm × 2.1 mm i.d., 1.7 μm; Waters Corp., USA). The ranges of the calibration curves were 1.0-1000.0 ng/mL for FLX and 0.2-1000.0 ng/mL for RIS and 9-OH-RIS. Linearity, recovery, precision, and stability were within the acceptable range. This method is rapid, fast, and precise for the determination of RIS and FLX in plasma and is applicable in pharmacokinetic studies.

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.

Development and validation of an HPLC-UV method for the quantification of carbamazepine in rabbit plasma

An isocratic simple rapid assay has been developed and validated for the determination of carbamazepine (CBZ) in both solution form and rabbit plasma using propylparaben as an internal standard. The assay was performed using a μ-Bondapak C18 (150 mm × 4.6 mm i.d) with a mobile phase consisting of methanol and water (50:50), the flow rate was 1 ml/min and UV detection at 285 nm. The method was found to be specific for CBZ, no interfering peaks were observed with an overall analytical run time of 15 min. Accuracy reported as % recovery were found to be 98.37-100.45% and 97.53-103.58% for inter-day and intra-day accuracies, respectively. Inter-day precision (reproducibility) was found to be 0.53-2.75% RSD, while intra-day precision (repeatability) was found to be 1.06-3.7% RSD for the samples studied. The calibration curve was found to be linear with the equation y = 0.2847x + 0.0138, with a correlation coefficient of 0.9999 (R (2)) over a concentration range of 0.5-40 μg/ml. The limit of quantitation was the lowest concentration. The method is simple and rapid and does not require any preliminary treatment of the sample. The method was fully validated.

Spectrophotometric Determination of Fluoxetine by Batch and Flow Injection Methods

A rapid, simple, and accurate spectrophotometric method is presented for the determination of fluoxetine by batch and flow injection analysis methods. The method is based on fluoxetine competitive complexation reaction with phenolphthalein-beta-cyclodextrin (PHP-beta-CD) inclusion complex. The increase in the absorbance of the solution at 554 nm by the addition of fluoxetine was measured. The formation constant for fluoxetin-beta-CD was calculated by non-linear least squares fitting. Fluoxetine can be determined in the range 7.0 x 10(-6)-2.4 x 10(-4) mol l(-1) and 5.0 x 10(-5)-1.0 x 10(-2) mol l(-1) by batch and flow methods, respectively. The limit of detection and limit of quantification were respectively 4.13 x 10(-6) mol l(-1) and 1.38 x 10(-5) mol l(-1) for batch and 2.46 x 10(-5) mol l(-1) and 8.22 x 10(-5) mol l(-1) for flow method. The sampling rate in flow injection analysis method was 80+/-5 samples h(-1). The method was applied to the determination of fluoxetine in pharmaceutical formulations and after addition to human urine samples.

Chemometrics-assisted simple UV-spectroscopic determination of carbamazepine in human serum and comparison with reference methods

In the present report, carbamazepine is determined on serum samples of real patients by a procedure completely assisted by chemometric tools. First, a response surface methodology based on a mixture design was applied in order to select the best conditions for the extraction step. Finally, partial least squares multivariate calibration (PLS-1) was applied to second-derivative UV spectra, eliminating a shift baseline effect that originated in the extraction procedure. The performance assessment included: (a) a three-level precision study, (b) a recovery study analyzing spiked samples, and (c) a method comparison with high-performance liquid chromatography (HPLC) and fluorescence polarization immunoassay (FPIA) applied on real patient samples. The obtained results show the potentiality of the presently studied methodology for the monitoring of patients treated with this anticonvulsant.

Quality of Phenobarbital Solid-dosage Forms in the Urban Community of Nouakchott (Mauritania)

PURPOSE

Epilepsy is a major public-health problem in Africa. The quality of available drugs is a limiting factor for an adequate management. The aim of this study was to describe the proportion of poor-quality phenobarbital (PB) solid-dosage forms and evaluate the factors associated with its quality in Nouakchott (Mauritania).

METHODS

A cross-sectional study was carried out within pharmacies, hospitals, and on the parallel market in March 2003. PB samples were bought by a native person and then assayed by a liquid chromatography method. A package was considered to be of good quality if the active-substance average content was between 85 and 115% of the stated content printed on the packet.

RESULTS

Forty-five pharmaceutical stores were visited, enabling us to collect 146 samples of PB. Three brand names were available in Nouakchott. They originated from France, Morocco, Senegal, and Egypt. Results: A prevalence of 13.7%[95% confidence interval (CI), 8.8-20.0] of poor-quality PB was found. All samples from Morocco were underdosed. The generic active content was satisfactory, but saccharose, an excipient with a potential side effects, was identified. Two factors associated with the good quality of PB have been put forward: tablets manufactured in France and loose packaging as generics conditioned in such a way were of good quality.

CONCLUSIONS

This study shows that the quality of antiepileptic drugs in Africa is still worrying. The setting up of medicine quality control in Mauritania is legitimate. Considering the good quality of generic PB and its lower cost, this type of medicine should be promoted in this region.

High performance liquid chromatographic and thin layer densitometric methods for the determination of risperidone in the presence of its degradation products in bulk powder and in tablets

Two reproducible stability indicating methods were developed for the determination of risperidone (RISP) in presence of its degradation products in pure form and in tablets. The first method was based on reversed phase high performance liquid chromatography (HPLC), on Lichrosorb RP C 18 column (250 mm i.d., 4 mm, 10 microm), using methanol:0.05 M potassium dihydrogen phosphate pH 7 (65:35 (v/v)) as the mobile phase at a flow rate of 1 ml min(-1) at ambient temperature. Quantification was achieved with UV detection at 280 nm over a concentration range of 25-500 microg ml(-1) with mean percentage recovery of 99.87 +/- 1.049. The method retained its accuracy in the presence of up to 90% of RISP degradation products. The second method was based on TLC separation of RISP from its degradation products followed by densitometric measurement of the intact drug spot at 280 nm. The separation was carried out on aluminum sheet of silica gel 60F254 using acetonitrile:methanol:propanol:triethanolamine (8.5:1.2:0.6:0.2 (v/v/v/v)), as the mobile phase, over a concentration range of 2-10 microg per spot and mean percentage recovery of 100.1 +/- 1.18. The two methods were simple, precise, sensitive and could be successfully applied for the determination of pure, laboratory prepared mixtures and tablets. The results obtained were compared with the manufacturer's method.

Sensitive chemiluminescence assay for risperidone in pharmaceutical preparations

A sensitive chemiluminescence (CL) method to determine the antipsychotic risperidone (RSP) is proposed, based on the catalytic effect of risperidone on the CL reaction between luminol and hydrogen peroxide in flow system. The increment of CL intensity was correlated with risperidone concentration in the range of 10pg ml(-1) to 1.0ng ml(-1) with a relative standard deviation of less than 5.0% (n = 5); and a limit of detection of 4pg ml(-1) (3sigma). At a flow rate of 2.0ml min(-1), the flow injection CL method exhibited both high sensitivity and excellent selectivity giving a throughput of 120 samples per hour. The proposed method was applied successfully to the determination of risperidone in pharmaceutical preparations.

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.

Quality control of commercial tablets containing the novel antipsychotic quetiapine

Quetiapine (bis [2-(2-[4-(dibenzo[b,f][1,4]thiazepin-11-yl]ethoxy)ethanol]fumarate) is the most recent agent introduced on the drug market for the treatment of psychotic disorders. Two different analytical methods for the quality control of quetiapine in commercial formulations have been developed and compared: a spectrophotometric method and a capillary zone electrophoretic (CZE) method. The spectrophotometric assay was carried out measuring the absorbance at a wavelength of 246 nm. The CZE method used an uncoated fused-silica capillary and a pH 2.5, 50 mM phosphate buffer as the background electrolyte. The detection wavelength was 205 nm, the separation voltage was 15 kV, and a complete electrophoretic run lasts less than 2.5 min. Extraction of quetiapine from the commercial tablets consisted of a simple one-step treatment with a pH 2.5, 50 mM phosphate buffer. Linearity was observed in the 5-25 microg ml(-1) concentration range of quetiapine for the spectrophotometric method, and in the 5-50 microg ml(-1) concentration range for the electrophoretic method. Both methods gave satisfactory results in terms of repeatability and intermediate precision (RSD<1.9%). Also accuracy values were very good for both methods, the recovery being between 98.2 and 100.5%.