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- Validation of two spectrophotometric methods for fluoxetine quantificationPublication . Gaspar, Joana; Barbosa Moreira, ZéliaObjective: This paper describes the development and validation of two UV-Visible spectrophotometric analysis methods, using absolute ethanol (method A) and HCl 0.1 M (method B) as solvents, to quantify fluoxetine (FLX) in its generic and brand name form. The objective is to validate both methods and compare the concentrations of the samples obtained from each one. Methods: Validation of each method with the determination of linearity, limit of detection and quantification, intermediary precision, robustness, accuracy and uniformity of mass for both samples was performed. Results: Uniform distribution of FLX in capsules were verified and good linear relationships were found between the readings and the concentrations of FLX, in the ranges of 100 μg/ml to 300 μg/ml and 5 μg/ml to 25 μg/ml, for method A and B, respectively. The limit of quantification obtained was 9.96 μg/ml for method A and 0.87 μg/ml for method B. The limit of detection obtained was 2.988 μg/ml for method A and 0.26 μg/ml for method B. Was also verified robustness, good inter-day precision and accuracy of both methods. Conclusion: The methods were successfully validated to the determination of FLX in its pharmaceutical formulations.
- Optimization of a dispersive liquid–liquid microextraction method followed by UHPLC analysis for fluoxetine quantification in environmental water resourcesPublication . Runfola, Massimiliano; Lima, Diana L.D.; Fonseca, Ana; Barbosa Moreira, ZéliaFluoxetine is the most prescribed drug for treatment of depression. Recently, its presence in aquatic environment has been receiving a growing interest as several studies assessed its effects on aquatic fauna. Therefore, it's important to have an analytical method capable of monitoring these compounds at low concentrations. In this study, a new method was developed based on dispersive liquid–liquid microextraction to preconcentrate fluoxetine in a small volume of water sample (6 mL) before chromatographic analysis using ultra high performance liquid chromatography with fluorescence detection. Effect of composition and volume of extracting mixture, sample pH, vortexing time and salt addition were evaluated. Optimization of extraction conditions lead to an enrichment factor of 61 ± 18. After extraction optimization, recovery percentages of fluoxetine spiked into different water matrices between 83–110% were obtained. For the optimized method, the calibration curve was obtained in the range of 160–2500 ng/L with a limit of detection of 98.9 ng/L and a limit of quantification of 329.8 ng/L.
- Positron emitting tracers in pre-clinical drug developmentPublication . Fernandes, E.; Barbosa Moreira, Zélia; Clemente, G.; Alves, F.; J. Abrunhosa, A.Molecular imaging tools such as Positron Emission Tomography (PET) are increasingly being used in the drug development process. The unrivaled sensitivity of PET coupled with a solid experience in developing highly targeted molecular probes makes this technique a very valuable tool at all stages from pre-clinical development to the clinical phases. Positron emitting tracers allow us to measure, quantitatively, molecular processes and interactions between a candidate drug and its molecular targets. This information can save time and money by directing development towards the most promising compounds and excluding molecules with unfavorable properties that would otherwise only be recognized as failures in latter stages of the process. In this paper we review the application of positron emitting tracers in the pre-clinical stages of the drug development process in the areas of oncology, cardiology, neurosciences and inflammatory diseases. PET tracers provide an important support for drug development in the areas of: discovery of new drug targets, clarification of pathophysiology, identification of potential drug candidates and validation of drug effectiveness, as well as the evaluation of pharmacokinetic and pharmacodynamic parameters in vivo.
- A novel semi-solid pill for stress-free voluntary oral drug administration in experimental rodentsPublication . Viana, Sofia; Martins, B.; Nunes, S.; Palavra, F.; Preguiça, I.; Alves, A.; Nóbrega, C.; Fernandes, R.; Silva, S.; Barbosa Moreira, Zélia; Lima, D.L.D.; Fontes-Ribeiro, Carlos; Reis, FlávioDuring compound screening and drug development, long-term oral drug administration to experimental rodents is often required. Oral gavage, a straightforward drug dosing technique, is not suitable for extended treatments considering the recurrent traumatic complications (gastroesophageal injury) and physiological distress (corticosterone levels alterations) that frequently bias experimental design outcomes. These reasons create a challenge for preclinical drug assays and stress-free/metabolic-inert alternatives of oral drug administration are warranted. Herein, it is presented an innovative semi-solid pill optimized to overcome aforementioned drawbacks. After a brief training period, C57BL/6 mice submitted to a chronic oral administration protocol (50 days) displayed a high index of voluntary acceptance of emptyand drug- (e.g. sitagliptin) incorporated vehicle in both healthy and CNS-diseased states. This protocol operates in a pair-housed animal housing fashion, allowing animal socialization throughout entire protocol. At the end of experiments, a normal neurobehavioral phenotype (anxiolytic, memory, locomotion parameters) was recorded. Moreover, this new methodology proved to be safe, preserving serum metabolic (glucose, triglycerides, total cholesterol), hepatic (albumin, total proteins) and renal (urea, creatinine, uric acid) parameters along with normal ileum contractility. Remarkably, coherent sitagliptin ( 10 mg/ml) plasma levels were detected, along with a robust decrease ( 80%) on the activity of its target (dipeptidyl peptidase- 4), unequivocally proving in vivo drug efficacy. Overall, this innovative approach may enclose a breakthrough advance for translational studies in scientific and pharmaceutical fields, providing a reproducible, efficient, metabolic inert and stress-free alternative for voluntary oral drug administration, with expected improvement on the data feasibility.