A liquid chromatography-miniature mass spectrometry (LC-Mini MS) method for quantitative analysis of risperidone and 9-hydroxyrisperidone in plasma.

Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is a universal method for the quantitative analysis of small molecular drugs in therapeutic drug monitoring (TDM). Alternatively, liquid chromatography-miniature mass spectrometry (LC-Mini MS) is a simple operating technique for quantitative analysis. However, the wide chromatographic peaks and long retention times of TDM samples using the LC-Mini MS system deteriorated the accuracy and efficiency of quantitative analysis. Here, an optimized electrospray ionization (ESI) interface setup with a splitter valve and a capillary needle (I.D. 30 µm and O.D. 150 µm) of the LC-Mini MS system was acquired. The chromatographic peaks were narrower and smoother and the retention time was shorter for TDM compounds. Furthermore, a quantitative analysis method for risperidone and the active metabolite 9-hydroxyrisperidone in plasma was developed based on this optimal LC-Mini MS setup. The results showed that the calibration curves of risperidone and 9-hydroxyrisperidone had good linear ranges of 2-100 ng mL-1 (R2 = 0.9931) and 2-100 ng mL-1 (R2 = 0.9915), respectively. Finally, the matrix effects, recoveries and stability of risperidone and 9-hydroxyrisperidone samples were analyzed. The results satisfied the requirements of quantitative validation in routine TDM procedures.

Characterization of bonded stationary phase performance as a function of qualitative and quantitative chromatographic factors in chaotropic chromatography with risperidone and its impurities as model substances.

Numerous stationary phases have been developed with the aim to provide desired performances during chromatographic analysis of the basic solutes in their protonated form. In this work, the procedure for the characterization of bonded stationary phase performance, when both qualitative and quantitative chromatographic factors were varied in chaotropic chromatography, was proposed. Risperidone and its three impurities were selected as model substances, while acetonitrile content in the mobile phase (20-30%), the pH of the aqueous phase (3.00-5.00), the content of chaotropic agents in the aqueous phase (10-100 mM), type of chaotropic agent (NaClO4, CF3COONa), and stationary phase type (Zorbax Eclipse XDB, Zorbax Extend) were studied as chromatographic factors. The proposed procedure implies the combination of D-optimal experimental design, indirect modeling, and polynomial-modified Gaussian model, while grid point search method was selected for the final choice of the experimental conditions which lead to the best possible stationary phase performance for basic solutes. Good agreement between experimentally obtained chromatogram and simulated chromatogram for chosen experimental conditions (25% acetonitrile, 75 mM of NaClO4, pH 4.00 on Zorbax Eclipse XDB column) confirmed the applicability of the proposed procedure. The additional point was selected for the verification of proposed procedure ability to distinguish changes in solutes' elution order. Simulated chromatogram for 21.5% acetonitrile, 85 mM of NaClO4, pH 5.00 on Zorbax Eclipse XDB column was in line with experimental data. Furthermore, the values of left and right peak half-widths obtained from indirect modeling were used in order to evaluate performances of differently modified stationary phases applying a half-width plots approach. The results from half-width plot approach as well as from the proposed procedure indicate higher efficiency and better separation performance of the stationary phase extra densely bonded and double end-capped with trimethylsilyl group than the stationary phase with the combination of end-capping and bidentate silane bonding for chromatographic analysis of basic solutes in RP-HPLC systems with chaotropic agents. Graphical abstract ᅟ.

Quantitative structure -retention relationship modeling of selected antipsychotics and their impurities in green liquid chromatography using cyclodextrin mobile phases.

Applying green chromatography methods is currently one of the challenges in liquid chromatography. Among different strategies, using cyclodextrin (CD) mobile phase modifiers was applied in this paper. CDs can form inclusion complexes with a wide variety of hydrophobic organic compounds and, consequently, affect their retention behavior. CD-containing mobile phases possess complicated complexation and adsorption equilibria so retention is dependent not only on chromatographic parameters and properties of the compound but also on properties of compound-CD complex. Docking study was used to calculate association constants of the selected antipsychotics (risperidone, olanzapine, and their impurities) and ß-CD complexes and predict which part of the molecule structure will most likely incorporate into the ß-CD cavity. Quantitative structure-retention relationship model (QSRR) for selected model substances was built employing artificial neural network (ANN) technique. Reliable QSRR model was obtained using molecular descriptors, complex association constants, and chromatographic factors. The multilayer perceptron network with 11-8-1 topology, trained with back propagation algorithm, showed the best performance. Root mean square error for training, validation, and test was 0.2954, 0.3633, and 0.4864, respectively. The correlation coefficient (R2) between experimentally obtained retention factor values [k(exp)] and values computed or predicted by ANN [k(ANN)] was 0.9962 for training, 0.9927 for validation, and 0.9829 for test, indicating good predictive ability of the model. The optimized network was used for development of green chromatography method for separation of risperidone and its related impurities, as well as olanzapine and its related impurities in a relatively short run time and with low consumption of organic modifier. The developed methods were validated in accordance with ICH Q2 (R1) quideline and all parameters fulfilled the defined criteria. The greenness of the proposed methods has also been demonstrated. Graphical Abstract Complex association constants as inputs of QSRR model in ß-cyclodextrin modified HPLC system and development of green chromatography methods.

High throughput µ-SPE based elution coupled with UPLC-MS/MS for determination of eluxadoline in plasma sample: Application in pharmacokinetic characterization of PLGA nanoparticle formulations in rats.

Eluxadoline is a novel µ- and κ-opioid receptor (OR) agonist and δ-OR antagonist, recently approved as a first line therapy for the treatment of irritable bowel syndrome. Due to abuse potential, poor bioavailability and high intersubject variability, a sensitive and reliable assay is prerequisite for its determination in biological samples. This work first time report the development and validation of UPLC-MS/MS assay for determination of eluxadoline in rat plasma sample using risperidone as an internal standard (IS). A high-throughput 96-well plate format µ-SPE technique was used for plasma sample extraction. The extracted samples were separated on Acquity BEH™ C18 column (100×2.1mm, 1.7µm) using mobile phase elution of acetonitrile: 20mM ammonium acetate (80:20, v/v) at a flow rate of 0.3mLmin-1. The precursor to product ion transition of m/z 570.16→118.12 (qualifier), 570.16→171.08 (quantifier) for eluxadoline, and m/z 411.18→191.07 for IS were used for MRM monitoring. The calibration curves were linear in concentration range of 0.15-50ngmL-1 with LOD and LOQ of 0.07 and 0.15ngmL-1, respectively. The validation results satisfied the criteria of USFDA and SWGTOX guidelines and were within the acceptable limit. Finally, the method was successfully applied in bioavailability enhancement study of the newly developed PLGA nanoparticles and Eudragit coated PLGA nanoparticles of eluxadoline in rats.

Stability of some atypical antipsychotics in human plasma, haemolysed whole blood, oral fluid, human serum and calf serum.

Long-term stability data of atypical antipsychotics in different matrices are not widely available. The aim of this work was to assess the stability of amisulpride, aripiprazole and dehydroaripiprazole, clozapine and norclozapine, olanzapine, quetiapine, risperidone and 9-hydroxyrisperidone, and sulpiride in human EDTA plasma, heparinised haemolysed human whole blood, oral fluid, human serum, and newborn calf serum stored in tightly capped plastic containers under a range of conditions. Measurements were performed by LC-MS/MS. Analyte instability was defined as a deviation of 15% or greater from the expected concentration. All analytes were stable following 3 freeze-thaw cycles in human plasma, and were stable in this matrix for at least 5 days at ambient temperature (olanzapine, 3 days); 4 weeks at 2-8°C (olanzapine, 2 weeks), and 2 years at -20°C (except for dehydroaripiprazole, olanzapine, and quetiapine, 1 year). In human serum, aripiprazole, dehydroaripiprazole, norclozapine, olanzapine, quetiapine, risperidone, 9-hydroxyrisperidone, and sulpiride were unstable after 5 days at ambient temperature, 3 weeks at 2-8°C, and 9 months at -20°C. Olanzapine was unstable in whole blood and oral fluid under most conditions studied, although prior addition of ascorbic acid had a moderate stabilising effect. All other analytes were stable in whole blood and oral fluid for at least 2 days at ambient temperature, 1 week at 2-8°C, and 2 months at -20°C (clozapine and norclozapine, 1 month whole blood). These results confirm that plasma (EDTA anticoagulant) is the sample of choice for TDM of atypical antipsychotics. Delayed (more than 1 week) analysis of patient samples should be undertaken with caution, especially with serum and with haemolysed whole blood. With olanzapine, only plasma collected and stored appropriately is likely to give reliable quantitative results.

LC-MS/MS of some atypical antipsychotics in human plasma, serum, oral fluid and haemolysed whole blood.

Therapeutic drug monitoring (TDM) of atypical antipsychotics is common, but published methods often specify relatively complex sample preparation and analysis procedures. The aim of this work was to develop and validate a simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the analysis of amisulpride, aripiprazole and dehydroaripiprazole, clozapine and norclozapine, olanzapine, quetiapine, risperidone and 9-hydroxyrisperidone, and sulpiride in small (200 µL) volumes of plasma or serum for TDM purposes. The applicability of the method as developed to haemolysed whole blood and to oral fluid was also investigated. Analytes and internal standards were extracted into butyl acetate:butanol (9+1, v/v) and a portion of the extract analysed by LC-MS/MS (100 mm × 2.1 mm i.d. Waters Spherisorb S5SCX; eluent: 50 mmol/L methanolic ammonium acetate, pH* 6.0; flow-rate 0.5 mL/min; positive ion APCI-SRM, two transitions per analyte). Assay calibration (human plasma, oral fluid, and haemolysed whole blood calibration solutions) was performed by plotting the ratio of the peak area of the analyte to that of the appropriate internal standard. Assay validation was as per FDA guidelines. Assay calibration was linear across the concentration ranges studied. Inter- and intra-assay precision and accuracy were within 10% for all analytes in human plasma. Similar results were obtained for oral fluid and haemolysed whole blood, except that aripiprazole and dehydroaripiprazole were within 15% accuracy at low concentration (15 µg/L) in oral fluid, and olanzapine inter-assay precision could not be assessed in these matrices due to day-by-day degradation of this analyte. Recoveries varied between 16% (sulpiride) and 107% (clozapine), and were reproducible as well as comparable between human plasma, human serum, calf serum and haemolysed whole blood. For oral fluid, recoveries were reproducible, but differed slightly from those in plasma suggesting the need for calibration solutions to be prepared in this medium if oral fluid is to be analysed. LLOQs were 1-5 µg/L depending on the analyte. Neither ion suppression/enhancement, nor interference from some known metabolites of the antipsychotics studied has been encountered. The method has also been applied to the analysis of blood samples collected post-mortem after dilution (1+1, 1+3; v/v) in analyte-free calf serum.

Solid phase microextraction and LC-MS/MS for the determination of paliperidone after stereoselective fungal biotransformation of risperidone.

The present work describes for the first time the use of SPME coupled to LC-MS/MS employing the polar organic mode in a stereoselective fungal biotransformation study to investigate the fungi ability to biotransform the drug risperidone into its chiral and active metabolite 9-hydroxyrisperidone (9-RispOH). The chromatographic separation was performed on a Chiralcel OJ-H column using methanol:ethanol (50:50, v/v) plus 0.2% triethylamine as the mobile phase at a flow rate of 0.8 mL min(-1). The SPME process was performed using a C18 fiber, 30 min of extraction time and 5 min of desorption time in the mobile phase. The method was completely validated and all parameters were in agreement with the literature recommendations. The Cunninghamella echinulata fungus was able to biotransform risperidone into the active metabolite, (+)-9-RispOH, resulting in 100% of enantiomeric excess. The Cunninghamella elegans fungus was also able to stereoselectively biotransform risperidone into (+)- and (-)-9-RispOH enantiomers at different rates.

A stability indicating HPLC method for the determination of electrochemically controlled release of risperidone.

A rapid stability indicating reversed-phase high-performance liquid chromatography (HPLC) method is developed for the determination of the electrochemically controlled risperidone release from a novel drug delivery system, based on the intrinsically conducting polymer (ICP), polypyrrole. The chromatographic separation was carried out on a C(18) column using acetonitrile-potassium dihydrogen phosphate (45:55, v/v, pH 6.5; 0.05 M) as the mobile phase. The isocratic flow is at 1.0 mL/min, with a runtime of 6 min, and the UV detection is at 237 nm. This provided a calibration curve linear over the range of 1-100 µg/mL. Intra-day and inter-day accuracy range between 98.4% and 102.6%, and the RSD for precision is <1.43%. The limit of detection and quantitation were determined to be 0.001 µg/mL and 0.01 µg/mL, respectively. The analytical method confirmed risperidone is stable for the oxidizing electric potential and the acidic environment involved during the manufacture and operation of the novel drug delivery system. The rate of risperidone release from polypyrrole depended on electrical stimulation applied to the polymer. This HPLC method is significantly faster than previously published methods and is the first to investigate the effect of an oxidizing potential on risperidone stability, which is essential for the evaluation of controlled delivery from an ICP-based system.

Sorption of emerging trace organic compounds onto wastewater sludge solids.

This work examined the sorption potential to wastewater primary- and activated-sludge solids for 34 emerging trace organic chemicals at environmentally relevant concentrations. These compounds represent a diverse range of physical and chemical properties, such as hydrophobicity and charge state, and a diverse range of classes, including steroidal hormones, pharmaceutically-active compounds, personal care products, and household chemicals. Solid-water partitioning coefficients (K(d)) were measured where 19 chemicals did not have previously reported values. Sludge solids were inactivated by a nonchemical lyophilization and dry-heat technique, which provided similar sorption behavior for recalcitrant compounds as compared to fresh activated-sludge. Sorption behavior was similar between primary- and activated-sludge solids from the same plant and between activated-sludge solids from two nitrified processes from different wastewater treatment systems. Positively-charged pharmaceutically-active compounds, amitriptyline, clozapine, verapamil, risperidone, and hydroxyzine, had the highest sorption potential, log K(d)=2.8-3.8 as compared to the neutral and negatively-charged chemicals. Sorption potentials correlated with a compound's hydrophobicity, however the higher sorption potentials observed for positively-charged compounds for a given log D(ow) indicate additional sorption mechanisms, such as electrostatic interactions, are important for these compounds. Previously published soil-based one-parameter models for predicting sorption from hydrophobicity (log K(ow)>2) can be used to predict sorption for emerging nonionic compounds to wastewater sludge solids.

Analysis of risperidone and 9-hydroxyrisperidone in human plasma, urine and saliva by MEPS-LC-UV.

Risperidone is currently one of the most frequently prescribed atypical antipsychotic drugs; its main active metabolite 9-hydroxyrisperidone contributes significantly to the therapeutic effects observed. An original analytical method is presented for the simultaneous analysis of risperidone and the metabolite in plasma, urine and saliva by high-performance liquid chromatography coupled to an original sample pre-treatment procedure based on micro-extraction by packed sorbent (MEPS). The assays were carried out using a C8 reversed-phase column and a mobile phase composed of 73% (v/v) acidic phosphate buffer (30 mM, pH 3.0) containing 0.23% triethylamine and 27% (v/v) acetonitrile. The UV detector was set at 238 nm and diphenhydramine was used as the internal standard. The sample pre-treatment by MEPS was carried out on a C8 sorbent. The extraction yields values were higher than 92% for risperidone and 90% for 9-hydroxyrisperidone, with RSD for precision always lower than 7.9% for both analytes. Limit of quantification values in the different matrices were 4 ng/mL or lower for risperidone and 6 ng/mL or lower for the metabolite. The method was successfully applied to plasma, urine and saliva samples from psychotic patients undergoing therapy with risperidone, with satisfactory accuracy results (recovery>89%) and no interference from other drugs. Thus, the method seems to be suitable for the therapeutic drug monitoring of schizophrenic patients using the three different biological matrices plasma, urine and saliva.

Validación del método analítico aplicable al estudio de estabilidad de risperidona solución oral 1 mg/mL / Validation of an analytical method applicable to study of 1 mg/mL oral Risperidone solution stability

Se validó un método analítico por cromatografía líquida de alta resolución, aplicable al estudio de estabilidad de risperidona solución oral 1 mg/mL. El método analítico validado resultó lineal, preciso, específico y exacto. Se desarrolló el estudio de estabilidad de la solución oral de risperidona 1 mg/mL y se determinó su fecha de vencimiento. El estudio de vida de estante se desarrolló por un periodo de 24 meses a temperatura ambiente; mientras que el estudio de estabilidad acelerada se efectuó sometiendo el producto a la influencia de la humedad y la temperatura; se realizó el análisis durante 3 meses. La formulación cumplió con las especificaciones de calidad descritas en la Farmacopea. Los resultados del estudio de estabilidad por vida de estante después de transcurridos los 24 meses indicaron que el producto mantiene los parámetros que determinan su calidad durante ese tiempo, y en los estudios acelerados no se observó degradación significativa (p> 0,05) del producto. Se estableció 2 años como fecha de vencimiento en las condiciones señaladas

A validated analytical method by high-performance liquid chromatography (HPLC) was applicable to study of 1 mg/mL Risperidone oral solution stability. The above method was linear, accurate, specific and exact. A stability study of the 1 mg/mL Risperidone oral solution was developed determining its expiry date. The shelf life study was conducted for 24 months at room temperature; whereas the accelerated stability study was conducted with product under influence of humidity and temperature; analysis was made during 3 months. Formula fulfilled the quality specifications described in Pharmacopeia. The results of stability according to shelf life after 24 months showed that the product maintains the parameters determining its quality during this time and in accelerated studies there was not significant degradation (p> 0.05) in the product. Under mentioned conditions expiry date was of 2 years

Validación del método analítico aplicable al estudio de estabilidad de risperidona solución oral 1 mg/mL / Validation of an analytical method applicable to study of 1 mg/mL oral Risperidone solution stability

Se validó un método analítico por cromatografía líquida de alta resolución, aplicable al estudio de estabilidad de risperidona solución oral 1 mg/mL. El método analítico validado resultó lineal, preciso, específico y exacto. Se desarrolló el estudio de estabilidad de la solución oral de risperidona 1 mg/mL y se determinó su fecha de vencimiento. El estudio de vida de estante se desarrolló por un periodo de 24 meses a temperatura ambiente; mientras que el estudio de estabilidad acelerada se efectuó sometiendo el producto a la influencia de la humedad y la temperatura; se realizó el análisis durante 3 meses. La formulación cumplió con las especificaciones de calidad descritas en la Farmacopea. Los resultados del estudio de estabilidad por vida de estante después de transcurridos los 24 meses indicaron que el producto mantiene los parámetros que determinan su calidad durante ese tiempo, y en los estudios acelerados no se observó degradación significativa (p> 0,05) del producto. Se estableció 2 años como fecha de vencimiento en las condiciones señaladas(AU)

A validated analytical method by high-performance liquid chromatography (HPLC) was applicable to study of 1 mg/mL Risperidone oral solution stability. The above method was linear, accurate, specific and exact. A stability study of the 1 mg/mL Risperidone oral solution was developed determining its expiry date. The shelf life study was conducted for 24 months at room temperature; whereas the accelerated stability study was conducted with product under influence of humidity and temperature; analysis was made during 3 months. Formula fulfilled the quality specifications described in Pharmacopeia. The results of stability according to shelf life after 24 months showed that the product maintains the parameters determining its quality during this time and in accelerated studies there was not significant degradation (p> 0.05) in the product. Under mentioned conditions expiry date was of 2 years(AU)

Evaluación comparativa de la liberación in vitro de risperidona 3 mg producida en Cuba contra Risperdal® / Comparative assessment of in vitro release of 3 mg Risperidone produced in Cuba versus Risperidal®

Se compararon los perfiles de disolución de las tabletas de risperidona 3 mg medicamento genérico producido en Cuba y del Risperdal® (Laboratorios Janssen-Cilag SA), para demostrar su similitud. También se realizó la comparación en varios medios de disolución a diferentes pH para evaluar una posible bioexoneración. Para la cuantificación del principio activo, se utilizó un método por cromatografía líquida de alta resolución, previamente validado. La comparación se realizó sobre la base de los factores de diferenciación y similitud. Los resultados mostraron que no existían diferencias en los perfiles de liberación para las tabletas producidas en Cuba y del producto innovador, así como para los diferentes medios de disolución a los pH utilizados.

The 3 mg Risperidone tablets dissolution profiles, a generic drug produced in Cuba and the Risperidal® (Janssen-Cilag SA Labs) were compared to demonstrate its similarity. Also, we compared some dissolution means at different pH to assess a potential bio-exoneration. To quantify the active principle, a previously validated high-performance liquid chromatography was used. The comparison was conducted on the base of differentiation and similarity factors. Results demonstrated that there weren't differences en release profiles for tablets produced in Cuba and of innovative product, as well as for the different dissolution means at pH used.

Estudio de estabilidad de tabletas de risperidona 3 mg / Study of stability of Risperidone (3 mg) tablets

Se desarrolló el estudio de estabilidad de las tabletas de risperidona 3 mg y se determinó su fecha de vencimiento. Este estudio se realizó por los métodos de vida de estante y de estabilidad acelerada mediante cromatografía líquida de alta eficiencia, validados en el Centro de Investigación y Desarrollo de Medicamentos. El estudio de vida de estante se desarrolló por un periodo de 24 meses a temperatura ambiente; mientras que el estudio de estabilidad acelerada se efectuó sometiendo el producto a la influencia de la luz, la humedad y la temperatura; se realizó el análisis durante 3 meses, para los 2 primeros y durante 6 meses para el estudio de la temperatura. La formulación de risperidona tabletas 3 mg cumplió con las especificaciones de calidad descritas en la Farmacopea. Los resultados del estudio de estabilidad por vida de estante después de transcurridos los 24 meses indican que el producto mantiene los parametros que determinan su calidad durante ese tiempo, y en los estudios acelerados no se observó degradación del producto. Se estableció 2 años como fecha de vencimiento en las condiciones señaladas.

Stability study was conducted of 3 mg Risperidone tablets determining its caducity date and using the shelf life methods and of accelerated stability by high-performance liquid chromatography validated in Drug Development and Research Center. The shelf life study was developed during 24 months at room temperature; whereas the accelerated stability study was performed subjecting the product to light, humidity and temperature influence. The 3 mg Risperidone tablets formula fulfilled the quality specifications described in Pharmacopeia. Results from shelf life study after 24 months show that the product maintains the parameters determining its quality during that time and in accelerated studies product degradation was noted. Under conditions signaled 2 years was established as the expiry date.

Estudio de estabilidad de tabletas de risperidona 3 mg / Study of stability of Risperidone (3 mg) tablets

Se desarrolló el estudio de estabilidad de las tabletas de risperidona 3 mg y se determinó su fecha de vencimiento. Este estudio se realizó por los métodos de vida de estante y de estabilidad acelerada mediante cromatografía líquida de alta eficiencia, validados en el Centro de Investigación y Desarrollo de Medicamentos. El estudio de vida de estante se desarrolló por un periodo de 24 meses a temperatura ambiente; mientras que el estudio de estabilidad acelerada se efectuó sometiendo el producto a la influencia de la luz, la humedad y la temperatura; se realizó el anßlisis durante 3 meses, para los 2 primeros y durante 6 meses para el estudio de la temperatura. La formulación de risperidona tabletas 3 mg cumplió con las especificaciones de calidad descritas en la Farmacopea. Los resultados del estudio de estabilidad por vida de estante después de transcurridos los 24 meses indican que el producto mantiene los parßmetros que determinan su calidad durante ese tiempo, y en los estudios acelerados no se observó degradación del producto. Se estableció 2 años como fecha de vencimiento en las condiciones señaladas(AU)

Stability study was conducted of 3 mg Risperidone tablets determining its caducity date and using the shelf life methods and of accelerated stability by high-performance liquid chromatography validated in Drug Development and Research Center. The shelf life study was developed during 24 months at room temperature; whereas the accelerated stability study was performed subjecting the product to light, humidity and temperature influence. The 3 mg Risperidone tablets formula fulfilled the quality specifications described in Pharmacopeia. Results from shelf life study after 24 months show that the product maintains the parameters determining its quality during that time and in accelerated studies product degradation was noted. Under conditions signaled 2 years was established as the expiry date(AU)

Evaluación comparativa de la liberación in vitro de risperidona 3 mg producida en Cuba contra Risperdal® / Comparative assessment of in vitro release of 3 mg Risperidone produced in Cuba versus Risperidal®

Se compararon los perfiles de disolución de las tabletas de risperidona 3 mg medicamento genérico producido en Cuba y del Risperdal® (Laboratorios Janssen-Cilag SA), para demostrar su similitud. También se realizó la comparación en varios medios de disolución a diferentes pH para evaluar una posible bioexoneración. Para la cuantificación del principio activo, se utilizó un método por cromatografía líquida de alta resolución, previamente validado. La comparación se realizó sobre la base de los factores de diferenciación y similitud. Los resultados mostraron que no existían diferencias en los perfiles de liberación para las tabletas producidas en Cuba y del producto innovador, así como para los diferentes medios de disolución a los pH utilizados(AU)

The 3 mg Risperidone tablets dissolution profiles, a generic drug produced in Cuba and the Risperidal® (Janssen-Cilag SA Labs) were compared to demonstrate its similarity. Also, we compared some dissolution means at different pH to assess a potential bio-exoneration. To quantify the active principle, a previously validated high-performance liquid chromatography was used. The comparison was conducted on the base of differentiation and similarity factors. Results demonstrated that there weren't differences en release profiles for tablets produced in Cuba and of innovative product, as well as for the different dissolution means at pH used(AU)

Analysis of risperidone and its metabolite in plasma and saliva by LC with coulometric detection and a novel MEPS procedure.

A new analytical method, based on the use of liquid chromatography with coulometric detection, has been developed and applied to quantify risperidone and its main active metabolite 9-hydroxyrisperidone in human plasma and saliva. The analytes were separated on a reversed phase C18 column, using a mobile phase composed of acetonitrile (26%) and a pH 6.5 phosphate buffer (74%). Pipamperone was used as the internal standard. A high sensitivity coulometric detection analytical cell containing two flow-through working electrodes was used: electrode 1 was set at +0.500V and electrode 2 at +0.700V. The detector response was linear over a plasma and saliva concentration range of 0.5-50.0ngmL(-1) for risperidone and 0.5-100.0ngmL(-1) for 9-hydroxyrisperidone. The limit of quantitation and the limit of detection for risperidone and 9-hydroxyrisperidone were 0.5ngmL(-1) and 0.17ngmL(-1), respectively. A novel clean-up procedure of biological samples was developed using the microextraction by packed sorbent technique, which gave good extraction yield for both the analytes, with absolute recovery values higher than 90.1%. The intra-day and the inter-day precision results, expressed by relative standard deviation values, were lower than 5.8%. Accuracy and selectivity assays were also satisfactory. The validated method has been successfully applied to the analysis of risperidone and 9-hydroxyrisperidone in plasma and saliva of psychiatric patients undergoing therapy with risperidone.

Determination of risperidone in tablets in the presence of its degradation products and placebo-derived constituents.

New chromatographic-densitometric assay was developed for identification and determination of risperidone in pharmaceutical formulations. Thin-layer chromatographic plates (TLC-F254) as a stationary phase and n-butanol-acetic acid-water (12:3:5 v/v/v) as a mobile phase were used for separation. Densitometric measurements were done for all constituents at lambda = 280 nm. A decrease in stability of risperidone was observed in acidic, basic and antioxidant solutions. Degradation of active pharmaceutical ingredient was consistent with first-order kinetics and unrelated to the solution. This assay is specific for risperidone. No interference of tablet origin adjuvants and degradation products were observed. Moreover, high sensitivity, limit of detection (0.22 microg/spot), limit of quantitation (0.67 microg/spot), recovery (98.2-100.82%), broad linear range (0.09 microg/spot to 1.40 microg/spot) and accuracy (1.87% RSD) are characteristic traits of the chromatographic-densitometric assay.

Time resolved analysis of risperidone and 9-hydroxy-risperidone in hair using LC/MS-MS.

Risperidone (RSP) is a second generation anti-psychotic drug used for the treatment of schizophrenia and anxiety disorders. In the last decades, clinical applications of hair analysis have received an increasing attention, because of its wide surveillance window. In this work, we describe a simple and fast method for detection and quantification of RSP and its major metabolite, 9-OH-risperidone (9-OH-RSP), in human hair. The validated method (cv of interday precision, intraday precision and accuracy<15%, r(2) of the calibration curves>0.98, limit of detection (LOD) was 0.90 pg/mg hair (RSP) and 1.52 pg/mg hair (9-OH-RSP), the lower limit of quantification (LLOQ) were 1.8 and 4.56 pg/mg, respectively, extraction yield were 86.9% for RSP and 86.7% for 9-OH-RSP) was successfully applied to quantify both substances in the hair of psychiatric patients treated with RSP. After washing, pulverisation, incubation in an ultrasound bath and liquid/liquid extraction of the hair samples, quantification was performed using LC/MS-MS in selected reaction monitoring mode with methaqualone as internal standard. Concentrations for RSP and its major metabolite ranged from 36 to 4765 pg/mg and from 14 to 57 pg/mg, respectively in the different hair segments. These preliminary results indicate a better relationship between the administered dose and hair concentration for 9-OH-RSP than for the parent drug. Furthermore, the RSP/9-OH-RSP ratio varied from 1 to 83.