A sensitive and fast ultra performance liquid chromatography‐electrospray ionization‐tandem mass spectrometry (UPLC‐ESI‐MS/MS) method for measurements of N‐butylscopolamine in plasma was developed and validated. A single protein precipitation was proposed for the clean up of the plasma and N‐methylhomatropine was added as internal standard (IS). The analyses were carried out using a C18 column and mobile phase of acetonitrile: 5 mM ammonium acetate + 0.1% formic acid (90:10, v/v). The triple quadrupole mass spectrometer equipped with an electrospray source in positive mode, was set up in selective reaction monitoring, to detect precursor → product ion 360.0 → 194.0 m/z and 290.3 → 138.0 m/z transitions, for N‐butylscopolamine and IS, respectively. The method was linear in 0.03 (lower limit of quantitation; LLOQ) – 10.00 ng/ml range for N‐butylscopolamine. Satisfactory selectivity, linearity, precision, accuracy, and robustness were obtained for the UPLC‐ESI‐MS/MS method. The proposed method was successfully applied to a pharmacokinetic study of healthy human volunteers; the results showed that the two scopolamine butylbromide formulations tested are not bioequivalent in rate and extent of absorption. Copyright © 2012 John Wiley & Sons, Ltd.

This study was to evaluate and compare the pharmacokinetic and pharmacodynamic behavior of two formulations of furosemide (CAS 54-31-9) 40 mg tablets, administered as a single dose to healthy subjects. Plasma concentrations of furosemide were determined with a validated method by liquid chromatography coupled to mass spectrometry (LC-MS/MS). We obtained the parameters: AUC 0-t , AUC 0-∞ , K el , T 1/2 , C max e T max. The following parameters were determined in urine: Sodium, Potassium and Chlorine and the total volume. The 90% confidence intervals for the ratio of C max (93.63-121.92%), AUC 0-t (96.80-115.72%) and AUC 0-∞ (98.45-117.43%) respectively for test and reference. Statistical analysis of the similarity of the parameters for urinary volume, excretion of sodium, potassium and chlorine and assuming that both formulations reach the same plasma levels, we expect that the pharmacological effect is also the same. Whereas the rate and extent of absorption, both products can be considered therapeutic equivalents.

A sensitive and specific LC/MS/MS method was developed and validated for the determination of scopolamine butylbromide in human plasma. Scopolamine butylbromide and propanolol (internal standard) were extracted from the plasma by liquidliquid extraction with dichloromethane as the extraction solvent and separated on a C18 analytical column (50 4.6 mm id) maintained at 40C. The analytes were eluted at a constant flow rate of 0.45 mL/min; the mobile phase consisted of acetonitrile and a buffer of 5 mM ammonium acetate and 0.1 formic acid (60 + 40, v/v). The mass spectrometer, equipped with an electrospray source in the positive ionization mode, was set up in the multiple-reaction monitoring mode to monitor the transitions m/z 360.6 > 102.5 (scopolamine butylbromide) and m/z 259.7 > 115.6 (propanolol). The chromatographic separation was obtained within 2.0 min, and the responses were linear over the concentration range of 0.1040.00 ng/mL. The mean extraction recoveries of scopolamine butylbromide and propanolol from plasma were 69.00 and 80.76, respectively. Method validation parameters, such as specificity, linearity, precision, accuracy, and stability, were within the acceptable range. Moreover, when the proposed method was successfully applied to a pharmacokinetic study of healthy human volunteers, the results showed that the two scopolamine butylbromide formulations tested are not bioequivalent in rate and extent of absorption.

Secnidazole is an antimicrobial agent used primarily in the treatment of amoebiasis. For this bioequivalence study of secnidazole, twenty-eight healthy female volunteers were enrolled in a randomized crossover study. Each volunteer was given a single oral dose of secnidazole test preparation and then the reference preparation, or vice versa, with a wash out interval of two weeks. The plasma concentrations of secnidazole were determined by HPLC, and the samples were extracted with tert-butyl-methyl-ether: dicloromethane (60:40, v/v). Secnidazole and its parent compound metronidazole were separated on a C18 column with water:acetonitrile (85:15, v/v) as the mobile phase, and monitored at 310 nm. The ratio of mean C max , AUC 0−t and AUC 0−∞ values for the test and reference products were within the predetermined range established by ANVISA, demonstrating that the two formulations are bioequivalent in rate and extent of absorption. Uniterms:Oral formulas/bioequivalence study. Secnidazole/bioavailability. Antimicrobials/ bioavailability. Secnidazol é um agente antimicrobiano utilizado principalmente no tratamento da amebíase. Para este estudo de bioequivalência de secnidazol em voluntários saudáveis, foram incluídos vinte e oito voluntárias mulheres no estudo randomizado cruzado. Cada voluntária recebeu uma única dose oral de secnidazol do produto teste e referência para comparação, com um intervalo de wash-out de duas semanas. As concentrações plasmáticas de secnidazol foram determinados por CLAE, as amostras foram extraídas com terc -butil-metil-éter: dicloromethano (60:40, v/v). O secnidazol e seu padrão interno metronidazol foram separados em uma coluna (C18 ) com fase móvel água ultra-pura:acetonitrila (85:15, v/v) e monitorado em 310 nm. As razões entre as médias geométricas de C máx , ASC 0-t e ASC 0-∞ , encontraramse dentro do estabelecido pela ANVISA, demonstrando que as formulações são bioequivalentes quanto à taxa e extensão de absorção Unitermos: Formulações orais/estudo de bioequivalência. Secnidazol/biodisponibilidade. Antimicrobianos/biodisponibilidade.

The purpose of this study is to compare the bioavailability of two itraconazole (CAS 84625-61-6) capsule formulations. An open, randomized, two-period crossover study with a 7-day washout interval was conduced in 32 healthy volunteers. The plasma samples were obtained up to 96 h after drug administration. A sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed and validated for the determination of itraconazole in human plasma. Itraconazole and ketoconazole (internal standard) were extracted from the plasma by liquid-liquid extraction using diethylether : dichloromethane (70 : 30) as extraction solvent and separated on a C8 analytical column (150 mm x 4.6 mm I.D.) maintained at 40 degrees C. The elution was performed by a constant flow rate of 1.2 mL/min and the mobile phase consisted of acetonitrile and acetic acid 0.1% (85 :15 v/v). The mass spectrometer equipped with an electrospray source in positive mode, was set up in multiple reaction monitoring, to detect parent --> production 705.0 392.0 (itraconazole) and 531.0 --> 81.70 (ketoconazole). The chromatographic separation was obtained within 3.5 min and was linear in the concentration range of 5 to 600 ng/mL. Bioequivalence between the products was determined by calculating 90% confidence intervals for the ratio of C(max) (95.02%-109.48%), AUC(0-t) (81.41%-107.77%) and AUC(0-inf) (80.85%-106.86%). These values for the test and reference products are within the 80-125% interval, proposed by FDA and EMEA. It was concluded that the proposed method was successfully applied to a pharmacokinetic study in healthy human volunteers, and results showed that the two itraconazole formulations are bioequivalent in their rate and extent of absorption.