Simultaneous determination of cocaine/crack and its metabolites in oral fluid, urine and plasma by liquid chromatography-mass spectrometry and its application in drug users.

INTRODUCTION: A single LC-MS equipment was used to validate three methods for simultaneously analyzing cocaine (COC), benzoylecgonine (BZE), cocaethylene (CE), anhydroecgonine methyl ester (AEME) and anhydroecgonine (AEC) in oral fluid (OF), urine and plasma. METHODS: The methods were carried out using a Kinetex HILIC column for polar compounds at 30°C. Mobile phase with isocratic condition of acetonitrile: 13mM ammonium acetate pH 6.0: methanol (55:35:10 v/v/v) at 0.8mL/min flow rate was used. RESULTS: After buffer dilution (OF) and protein precipitation (urine and plasma), calibration curve ranges were 4.25-544ng/mL for oral fluid and 5-320ng/mL for urine and plasma with correlation coefficients (r) between 0.9947 and 0.9992. The lowest concentration of the calibration curves were the lower limit of quantification. No major matrix effect could be noted, demonstrating the efficiency of the cleaning procedure. DISCUSSION: The methods were fully validated and proved to be suitable for analysis of 124 cocaine and/or crack cocaine users. Among the subjects, 56.5% reported daily use of cocaine in the previous three months. Results show a high prevalence of the analytes, with BZE as the most prevalent (94 cases), followed by COC (93 cases), AEC (70 cases), CE (33 cases) and AEME (13 cases). In addition, the concentration of BZE in urine was higher compared to OF and plasma found in the real samples, showing the facility of accumulation in chronic users in matrices with a large detection window.

Development and validation of a bioanalytical method for five antidepressants in human milk by LC-MS.

The use of medications during lactation is a common practice; however, pharmacological treatments impose serious doubts to both professionals and nursing mothers regarding the safety of drugs used during this period. Most of drugs are excreted in breast milk and there is great variability in the amount of analytes that can be received by the infant. Dilemmas about breastfeeding arise most commonly in relation to postpartum depression. Depression is a major clinical problem during the postpartum period and the vulnerability to onset or recurrence of depressive symptoms increases the possibility of psychotropic drug use during lactation. Selective inhibitors of serotonin reuptake are commonly prescribed for the treatment of depressive disorders, including fluoxetine, sertraline, citalopram, and paroxetine. A validated bioanalytical method using liquid chromatography coupled to mass spectrometry was developed and validated for determination of antidepressants in human milk following protein precipation. The bioanalytical method was successfully applied to assess milk samples from nursing mothers. From found concentrations, infant absolute (4.36-12.26µg/kg/day) and relative dose (0.60-2.90%,) were estimated and low values were obtained indicating safe use during laction. However, other factors such as complemantary feeding and hepatic or renal disorders in the infant should be considered.

Cocaine and crack cocaine abuse by pregnant or lactating mothers and analysis of its biomarkers in meconium and breast milk by LC-MS-A review.

Abusive use of drugs is a public health problem worldwide. The use of these substances by pregnant or lactating women can have many serious side effects in newborns. Among the commonest causes of addiction in drug users is cocaine in powdered form, inhaled, intravenously injected or smoked form (crack). Fast screening and a confirmation test using high specificity and sensitivity instruments such as LC-MS or GC/MS, can provide data to qualify and quantify chemical substances present in biological samples such as breast milk or meconium. Cocaine and/or crack can be detected through biomarkers or the unchanged molecule, enabling the form of cocaine use to be distinguished through the analytes. These methods must be carefully developed and validated according to internationally recognized guidelines. Thus, the study of biological matrices in which it can be detected through the development of simple and quick analytical methods can help prevent intoxication and diagnose the symptoms of dependency such as seizures, especially in babies, providing appropriate medical care.

Analysis of cocaine/crack biomarkers in meconium by LC-MS.

Fetal exposure to illicit drugs is a worldwide problem, since many addicted women do not stop using it during pregnancy. Cocaine consumed in powdered (snorted or injected) or smoked (crack cocaine) form are harmful for the baby and its side effects are not completely known. Meconium, the first stool of a newborn, is a precious matrix usually discarded, that may contain amounts of substances consumed in the last two trimesters of pregnancy. Analyzing this biological matrix it is possible to detect the unaltered molecule of cocaine (COC) or its metabolite benzoylecgonine (BZE) and pyrolytic products anhydroecgonine methyl ester (AEME) and anhydroecgonine (AEC). A liquid chromatography mass spectrometry (LC-MS) method was validated for meconium samples after solvent extraction, followed by direct injection of 10µL. Linearity covered a concentration range of 15 to 500ng/mg with a lower limit of quantification (LLOQ) of 15ng/mg for all analytes. Matrix effect was evaluated and showed adequate results. Detection of illicit substances usage can be crucial for the baby, since knowing that can help provide medical care as fast as possible. The method proved to be simple and fast, and was applied to 17 real meconium samples.

Determination of cocaine/crack biomarkers in colostrum by LC-MS following protein precipitation.

Drug abuse by nursing mothers is an ongoing concern because it may cause many adverse effects to the newborns. The development of analytical methods to analyze drugs of abuse in colostrum (first milk produced after birth) has a huge importance, because it enables the monitoring and the correct follow-up to users and newborns. A liquid chromatography mass spectrometry (LC-MS) method was developed and validated for the determination of cocaine and smoked cocaine (crack) biomarkers in colostrum. Cocaine (COC) and its major metabolite benzoylecgonine (BZE), the pyrolytic products anhydroecgonine methyl ester (AEME) and anhydroecgonine (AEC) were analyzed after a simple protein precipitation procedure using atropine (ATP) as internal standard (IS). Applying a chemometric approach study, all peaks were chromatographically separated at isocratic condition with a Kinetex HILIC column for polar compounds, at 30°C in 12min. One ion was detected for the quantification and three ions for confirmation of each analyte. The method was linear for all analytes in the concentration range of 5-300ng/mL with correlation coefficients (r) between 0.9983 and 0.9996. The lower limit of quantification (LLOQ) was 5ng/mL with acceptable validation parameters. Matrix effect was assessed by post-extraction addition approach and showed good results, demonstrating that protein precipitation cleaning procedure is fast, reliable and demand small quantities of organic solvent. The LC-MS method is fast and cheap compared to other equipments and was also successfully applied to assess real samples of colostrum from nursing mothers who were suspect of cocaine/crack abuse.

Development and validation of a stability-indicating capillary zone electrophoretic method for the assessment of entecavir and its correlation with liquid chromatographic methods.

A stability-indicating capillary zone electrophoresis (CZE) method was validated for the analysis of entecavir in pharmaceutical formulations, using nimesulide as an internal standard. A fused-silica capillary (50 µm i.d.; effective length, 40 cm) was used while being maintained at 25°C; the applied voltage was 25 kV. A background electrolyte solution consisted of a 20 mM sodium tetraborate solution at pH 10. Injections were performed using a pressure mode at 50 mbar for 5 s, with detection at 216 nm. The specificity and stability-indicating capability were proven through forced degradation studies, evaluating also the in vitro cytotoxicity test of the degraded products. The method was linear over the concentration range of 1-200 µg mL(-1) (r(2) = 0.9999), and was applied for the analysis of entecavir in tablet dosage forms. The results were correlated to those of validated conventional and fast LC methods, showing non-significant differences (p > 0.05).

Determination of fluticasone propionate in nasal sprays by a validated stability-indicating MEKC method.

A micellar electrokinetic chromatography method (MEKC) is developed and validated for the analysis of fluticasone propionate (FP) in nasal sprays. The MEKC method is performed on a fused-silica capillary (50 mum i.d.; effective length, 40 cm). The background electrolyte consists of 25 mM borate and 25 mM anionic detergent SDS solution at pH 9. The capillary temperature is maintained at 35 degrees C, and the applied voltage is 20 kV. The injection is performed using the hydrodynamic mode at 50 mbar for 6 s with detection at 238 nm. The method is linear in the range of 2-80 mug/mL (r(2) = 0.9956). The specificity and stability-indicating capability are proven through forced degradation studies inclusive by mass spectrometry, which also shows that there is no interference of the excipients. The limit of detection and limit of quantitation are 0.56 and 2 mug/mL, respectively. Moreover, method validation demonstrates acceptable results for accuracy, precision, and robustness. The proposed method was successfully applied for the quantitative analysis of FP nasal sprays, and the results were compared to a validated reversed-phase liquid chromatographic method, showing non-significant difference (P > 0.05).

A high-throughput liquid chromatography tandem mass spectrometry method for the comparative determination of fluticasone propionate by reversed-phase liquid chromatography and capillary electrophoresis methods in pharmaceutical nasal sprays.

A simple, specific, rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the analysis of fluticasone propionate (FP) in pharmaceutical formulations was developed and validated using deflazacort as internal standard (IS). The LC-MS/MS method was carried out on a C8 column (50 mm) with a mobile phase consisted of methanol : water (95 : 5, v/v) 100 mM formic acid-50 mM ammonium acetate (90 : 5 : 5, v/v/v). The mass spectrometry method was performed employing positive atmospheric pressure chemical ionization technique, operating in multiple reaction monitoring mode. The chromatographic separation was obtained within 1.5 min and it was linear in the concentration range of 10-1000 ng mL(-1). Moreover, method validation demonstrates acceptable results for the specificity, accuracy, precision and robustness. The proposed method was successfully applied for the quantitative analysis of FP nasal sprays and the results were compared to validated liquid chromatography and capillary electrophoresis methods with photodiode array detectors showing non-significant difference (P > 0.05).

Development and validation of a capillary zone electrophoresis method for assessment of recombinant human granulocyte colony-stimulating factor in pharmaceutical formulations and its correlation with liquid chromatography methods and bioassay.

A capillary zone electrophoresis (CZE) method was validated for the analysis of recombinant human granulocyte colony-stimulating factor (rhG-CSF) and performed on a fused-silica capillary, with detection at 195 nm. The background electrolyte solution consisted of 50 mM sodium tetraborate solution at pH 9. The method was linear in the concentration range of 1-200 microg/mL and the limit of quantitation (LOQ) was 1 microg/mL, with acceptable validation parameters. The method was applied for the analysis of pharmaceutical formulations, and the results were correlated to the reversed-phase HPLC method (RP-HPLC), size-exclusion HPLC method (SE-HPLC) and in vitro bioassay method.

Avaliação de pirogênios em produtos de uso veterinário pelos testes da hipertermia em coelhos e do lisado de amebócitos do Limulus / Pyrogens in veterinary products by the rabbit pyrogen test and the Limulus amoebocyte lysate test

Realizou-se a avaliação de pirogênios em produtos veterinários de uso parenteral, pelo método da hipertermia em coelhos, calculando-se, para o teste das amostras, doses com concentrações de três a sete vezes superiores à terapêutica. Preconizou-se como resposta positiva o aumento de temperatura de 0,6°C. Utilizou-se também o ensaio do lisado de amebócitos do Limulus (LAL) por geleificação, semiquantitativo, executando o teste de interferentes, validando o procedimento e estabelecendo a máxima diluição válida para a análise de cada produto. Paralelamente, efetuou-se avaliação comparativa de amostras com o método do LAL cromogênico, quantitativo, demonstrando correlação e reprodutibilidade dos resultados. Avaliaram-se vinte e oito produtos de diferentes classes farmacológicas, observando-se que dois não cumpriram as especificações, sendo reprovados. Sugere-se que as especificações estudadas sejam adotadas, contribuindo para aprimorar o controle de contaminantes, garantindo a qualidade e a segurança dos produtos veterinários.

The rabbit pyrogen test was used to evaluate veterinary products, suggesting the temperature rise of 0.6°C as the ending point for the positive results. The test doses were calculated based on the therapeutic dose increased from three to seven times. The semi-quantitative Limulus amoebocyte lysate (LAL) gel clot test was performed and compared to the LAL spectrophotometric chromogenic, quantitative assay. The comparative evaluation of the samples showed correlation and reproducibility of the results. The interference test was carried out, the procedure validated and the maximum valid dilution established for the analysis of the products without Pharmacopoeial specifications. Two of the twenty-eight products of different pharmacological groups evaluated didn't meet the requirements and were reproved. The specifications investigated are suggested to be used for the purity evaluation of the veterinary parenteral products, as a contribution to assure the quality and safety of the products.