Search results for "Preparation"
showing 10 items of 939 documents
Sample Preparation Improvement in Polycyclic Aromatic Hydrocarbons Determination in Olive Oils by Gel Permeation Chromatography and Liquid Chromatogr…
2005
Abstract The determination of 15 polycyclic aromatic hydrocarbons (PAHs) in olive oil samples has been improved in order to obtain a fast methodology with a low limit of detection through the combination of liquid–liquid extraction with acetonitrile and preparative gel permeation chromatography (GPC) prior to the injection of purified extracts into a C18 column. Acetonitrile–water was used as the mobile phase with a gradient from 50 to 95%, w/w, acetonitrile in 30 min. The oven temperature was maintained at 15°C, and fluorometric detection was made at a fixed excitation wavelength of 264 nm and variable, optimal emission wavelength for each analyte ranging from 352 nm for 11-H-benzo(b)fluor…
Development of a sensitive method for the determination of acrylamide in coffee using high-performance liquid chromatography coupled to a hybrid quad…
2015
The emerging trend towards high-resolution mass spectrometry (MS) alternatives was evaluated by the application of Orbitrap MS for the determination of acrylamide in coffee samples. The high resolving power of the Orbitrap MS provided the high selectivity and sensitivity that enabled quantitative analysis of acrylamide in complex matrices, such as coffee. Several sample preparation methods and scanning modes of the MS (full MS, t-SIM, t-MS2) were assessed in order to optimise parameters of the analytical method. The final procedure involved the extraction of acrylamide with acetonitrile, solid-phase extraction with dispersive primary secondary amine (PSA) and amino columns, and the detectio…
Application of LA-ICP-MS as a rapid tool for analysis of elemental impurities in active pharmaceutical ingredients.
2014
The control of inorganic contaminants in active pharmaceutical ingredients has a significant role in the quality control of drug products. The concentration limits for metal residues in drug products have been defined by various regulatory guidelines. Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is a powerful and fast analytical technique for multi-elemental analysis. A disadvantage in using LA-ICP-MS method is the lack of matrix reference materials for validation and calibration purposes. This article focuses on the handling strategy of laboratory-made matrix calibration standards for the quantification of elemental impurities in an active pharmaceutical ingredie…
Pefloxacine mesilate- and ofloxacin-loaded polyethylcyanoacrylate nanoparticles: characterization of the colloidal drug carrier formulation.
1995
The entrapment of fluoroquinolones, perfloxacine mesilate (PFX) and ofloxacin (OFX), in polyalkylcyanoacrylate (PECA) nanoparticles could offer some advantages for their biological application; for examples, increasing their bioavailability, controlling the drug time-release in blood, and reducing the formation of bacterial resistance. To load these two drugs in PECA polymeric bulk, the incorporation or adsorption method was performed. These two methods were capable of influencing nanoparticle size, molecular weight, release profile, and drug–polymer association. The incorporation method, particularly for the OFX system, achieved PECA nanoparticle suspensions with a mean size value three ti…
Strategies for Active Learning to Improve Student Learning and Attitudes Towards Physics
2021
Over the last several years, active learning methods and strategies have received considerable attention from the educational community and are commonly presented in the related literature as a credible solution to the reported lack of efficacy of more “traditional” educative approaches. Research has shown that a possible factor is the strongly contextualized nature of active learning that focuses on the interdependence of situation and cognition. In this paper, we report the results of a Symposium with different contributions in the field of research on active learning. We start with a system analysis of the mental processes involved in learning physics which explains how active learning i…
Intervenciones individuales para mejorar la adherencia al tratamiento farmacéutico, la dieta y la actividad física en adultos con hipertensión primar…
2020
Introduction Hypertension is a chronic disease with 31% worldwide prevalence in adults. It has been associated with non-adherence to therapeutic regime with a negative impact on the prognosis of the disease and healthcare-associated costs. So, it is necessary to identify effective interventions to improve adherence among the afflicted population. The objective of this protocol is to describe the methods for a systematic review that will evaluate the effect of individual interventions so as to improve adherence to the prescribed pharmacological treatment, as well as to prescribed diet and physical activity in adults with primary hypertension. Methods and analysis A systematic search of studi…
Does Preoperative Treatment with a Gonadotropin-Releasing Hormone Agonist Improve the Outcome of Endometrial Resection?
1998
Abstract Study Objective. To verify if more favorable long-term results of endometrial resection can be obtained with preoperative gonadotropin-releasing hormone (GnRH) agonist treatment. Design. Multicenter, randomized, controlled trial (Canadian Task Force classification I). Setting. Tertiary care academic department. Patients. Sixty-three premenopausal women with established menorrhagia. Intervention. Eight weeks of goserelin depot treatment before endometrial resection or immediate surgery in the early proliferative phase of the cycle. Measurements and Main Results. Variations in menstrual patterns and bleeding scores as well as overall degree of satisfaction with treatment were determi…
New spectrophotometric procedure for determining cefotaxime based on derivatization with 1,2-naphthoquinone-4-sulphonate into solid-phase extraction …
1998
Cefotaxime was derivatised with 1,2-naphthoquinone-4-sulphonate (NQS), extracted into solid-phase cartridges (C18) and detected using a UV-visible detection system. Optimum conditions for this new procedure were: hydrogencarbonate-carbonate buffer, pH 10.5, 5-min reaction time at 25 degrees C and an NQS concentration of 7.1x10(-3) mol l(-1). The accuracy and the precision of the liquid-solid procedure were tested. The procedure was used to measure cefotaxime in pharmaceutical and urine samples. The results obtained were contrasted with those reported for a HPLC method for urine samples. The generalized H-point standard additions method was used to measure cefotaxime in urine samples.
Clinical and Microbiologic Effects of Subgingival Controlled-Release Delivery of Chlorhexidine Chip in the Treatment of Periodontitis: A Multicenter …
2008
Background: The main therapeutic approach for periodontal diseases is mechanical treatment of root surfaces via scaling and root planing (SRP). Multicenter clinical trials have demonstrated that the adjunctive use of a chlorhexidine (CHX) chip is effective in improving clinical results compared to SRP alone. However, some recent studies failed to confirm these clinical results, and conflicting results were reported regarding the effects of the CHX chip on subgingival microflora. The aim of this study was to provide further data on the clinical and microbiologic effects of CHX chips when used as an adjunct to SRP. Methods: A total of 116 systemically healthy individuals with moderate to adva…
Tacrolimus effects and side effects after liver transplantation: is there a difference between immediate and extended release?
2012
Abstract Background Immunosuppressive therapy after orthotopic liver transplantation (OLT) requires a high degree of patient compliance to guarantee safety and avoid side effects. In 2007, prolonged-release tacrolimus was launched in Europe to improve compliance. In this prospective observational crossover single-center trial, we analyzed effects and side effects of prolonged-release tacrolimus in OLT patients. Methods LT patients at our center were included if they were older than l8 years of age, had had the procedure at least 6 months prior, and were outpatients currently on twice-daily tacrolimus. Patients were observed for 6 months before switching to once-daily tacrolimus. Patient his…