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- Sample preparation and chromatographic methods for the determination of protein-bound uremic retention solutes in human biological samples: An overviewPublication . Fernandes, Sara R.; Meireles, Andreia N.; Marques, Sara S.; Silva, Luís; Barreiros, Luisa; Sampaio-Maia, Benedita; Miro, Manuel; Segundo, Marcela A.Protein-bound uremic retention solutes, such as indole-3-acetic acid, indoxyl sulfate, p-cresol and p-cresol sulfate, are associated with the development of several pathologies, namely renal, cardiovascular, and bone toxicities, due to their potential accumulation in the human body, thus requiring analytical methods for monitoring and evaluation. The present review addresses conventional and advanced sample treatment procedures for sample handling and the chromatographic analytical methods developed for quantification of these compounds in different biological fluids, with particular focus on plasma, serum, and urine. The sample preparation and chromatographic methods coupled to different detection systems are critically discussed, focusing on the different steps involved for sample treatment, namely elimination of interfering compounds present in the sample matrix, and the evaluation of their environmental impact through the AGREEprep tool. There is a clear trend for the application of liquid-chromatography coupled to tandem mass spectrometry, which requires protein precipitation, solid-phase extraction and/or dilution prior to analysis of biological samples. Furthermore, from a sustainability point of view, miniaturized methods resorting to microplate devices are highly recommended.
- Fast monolith-based chromatographic method for determination of methotrexate in drug delivery studiesPublication . Barbosa, Ana Isabel; Fernandes, Sara; Machado, Sandia; Sousa, Patrícia; Sze, Ong Yong; Silva, Eduarda M.P.; Barreiros, Luisa; Lima, Sofia A.C.; Reis, Salette; Segundo, Marcela A.Methotrexate (MTX) is a derivative of aminopterin, used as an anticancer or an anti-inflammatory agent. The development of suitable drug delivery systems containing MTX is an active area of research, requiring suitable analytical methods. Therefore, a high-throughput HPLC method is proposed for determination of MTX in the delivery system and permeation studies. Chromatographic separation was achieved on a reversed phase monolithic C18 column using isocratic elution (phosphate buffer (pH 7.0, 10 mM)-ACN (91:9, v/v)) and spectrophotometric detection at 302 nm. Total run time was 3.5 min, with MTX retention time of 2.1 min, providing 17 determinations per hour. The method was found to be specific, accurate (99.2–110%) and precise for intra-day (RSD ≤ 3.5%) and inter-day assays (RSD ≤ 3.4%). MTX showed stability after 24 h at room temperature or in the autosampler (4 °C) and over three freeze-thaw cycles with recoveries ≥94.2%. The validated method was successfully applied to establish in vitro drug release profile of MTX delivered by lipid nanoparticles. Application to pig skin permeation media provided mean recovery values ranging from 94.1 to 101.6% (RSD ≤ 1.1%).
- Chemistry, bioactivities, extraction and analysis of azadirachtin: State-of-the-artPublication . Fernandes, Sara; Barreiros, Luisa; Ferraz Oliveira, Rita; Cruz, Agostinho; Prudêncio, Cristina; Oliveira, Ana Isabel; Pinho, Cláudia; Santos, Nuno; Morgado, JoaquimAzadirachta indica A. Juss. (Neem) is an Indian tree recognized for its activity as pesticide, as well as several pharmacological properties. Among the various compounds already isolated and studied from Neem tree, azadirachtin (AZA) was identified as the main bioactive compound. Azadirachtin can be found at different parts of the Neem plant but assumes its maximum concentration at the seed level. This compound features a quite complex chemical structure, which justifies the 20-plus-year difficulty to identify the synthetic pathway that subsequently permitted to carry out its artificial synthesis. Azadirachtin is widely used as a basis for production of biopesticides; nevertheless, other properties have been recognized for this substance, among which the anticancer and antimalarial activity stand out. The methods available for azadirachtin extraction are diverse, including solid-liquid extraction and extraction with solvents at high or low temperatures. Alcohol based solvents are associated with higher extraction yields and are therefore preferred for the isolation of azadirachtin from plant parts. Clean-up of the extracts is generally required for further purification. The highest azadirachtin levels have been obtained from Neem seeds but concentration values present a large variation between batches. Therefore, in addition to extraction procedures, it is essential to establish routine methods for azadirachtin identification and quantification. Chromatography-based techniques are preferably selected for detection and quantification of azadirachtin in plant matrices. Overall, this process will guarantee a future reproducible, safe and effective use of the extracts in formulations for commercial applications.
- Insights on Ultrafiltration-Based Separation for the Purification and Quantification of Methotrexate in NanocarriersPublication . Marques, Sara S.; Ramos, Inês I.; Fernandes, Sara; Barreiros, Luisa; Lima, Sofia A. C.; Reis, Salette; Domingues, M. Rosário M.; Segundo, Marcela A.The evaluation of encapsulation efficiency is a regulatory requirement for the characterization of drug delivery systems. However, the difficulties in efficiently separating nanomedicines from the free drug may compromise the achievement of accurate determinations. Herein, ultrafiltration was exploited as a separative strategy towards the evaluation of methotrexate (MTX) encapsulation efficiency in nanostructured lipid carriers and polymeric nanoparticles. The effect of experimental conditions such as pH and the amount of surfactant present in the ultrafiltration media was addressed aiming at the selection of suitable conditions for the effective purification of nanocarriers. MTX-loaded nanoparticles were then submitted to ultrafiltration and the portions remaining in the upper compartment of the filtering device and in the ultrafiltrate were collected and analyzed by HPLC-UV using a reversed-phase (C18) monolithic column. A short centrifugation time (5 min) was suitable for establishing the amount of encapsulated MTX in nanostructured lipid carriers, based on the assumption that the free MTX concentration was the same in the upper compartment and in the ultrafiltrate. The defined conditions allowed the efficient separation of nanocarriers from the free drug, with recoveries of >85% even when nanoparticles were present in cell culture media and in pig skin surrogate from permeation assays.
- O contributo da reconciliação terapêutica para a utilização segura e eficaz de medicamentosPublication . Teixeira, S.; Fernandes, Sara; Oliveira, RitaOs erros de medicação apresentam-se como uma importante causa de eventos adversos em pacientes hospitalizados, nomeadamente em momentos de transição de cuidados de saúde, tendo acrescidos custos significativos e implicações para a saúde e bem-estar dos pacientes. A reconciliação terapêutica tem sido reconhecida como um processo importante nos momentos de transição de cuidados de saúde para evitar erros de medicação, permitindo a obtenção de uma lista completa e actualizada de todos os medicamentos que o doente faz em regime de ambulatório e compará-la com a prescrição médica realizada nos momentos de transição de cuidados de saúde. Avaliar a importância da prática da reconciliação terapêutica na minimização e interceção de erros de medicação na admissão e alta hospitalar; averiguar a frequência, tipo e importância clínica dos erros de medicação nestes momentos; discutir a importância dos sistemas eletrónicos e dos profissionais de farmácia na prática da reconciliação terapêutica. Efetuou-se uma revisão bibliográfica de artigos publicados a partir de 2006 sobre a temática, obtidos em diferentes bases de dados online (PubMed, B-on, Ebsco), e que respeitassem os objetivos propostos. Foram analisados 17 artigos, cujos estudos foram realizados em diversos serviços hospitalares (medicina geral, unidade de cuidados intensivos, unidades de cirurgia geral e cardiovascular, serviços de urgência, cardiologia, pneumologia, traumatologia e neurocirurgia), bem como em diferentes momentos de transição de cuidados de saúde, mais precisamente, na admissão e alta hospitalar. Os estudos analisados demonstram que a reconciliação terapêutica possibilita a minimização e intercepção de erros de medicação proporcionando uma maior segurança ao paciente. A reconciliação terapêutica é assim um elemento importante da segurança do paciente, sendo uma prática essencial para reduzir os erros de medicação em torno das hospitalizações bem como de todas as consequências associadas aos mesmos. É importante ainda destacar o profissional de farmácia e os sistemas eletrónicos como aliados preponderantes para a aplicação desta prática de forma eficaz. Desta forma, a reconciliação terapêutica pode e deve ser vista como um ponto de partida para a realização de um seguimento farmacoterapêutico com o intuito de promover o uso racional de medicamentos e promover a segurança contínua do paciente.
- Occupational and environmental exposure to anticancer drugsPublication . Teles, Luís; Fernandes, Sara; Cruz, Agostinho; Vieira da Silva, Manuela; Amorim, Manuela; Vieira, Mónica; Barros, PiedadeThe use of anticancer drugs is not restricted to a single type of drug (Connor et al. , 1999; Suspiro & Prista, 2012). These are varied and present diverse mechanisms of action, which may be causes of occupational exposure. Despite the restricted and controlled use of cytotoxic agents, the risk involved is not confined to individuals who administer them but also to all health care professionals and general population directly or indirectly in contact with them (Suspiro & Prista, 2012). The presence of pharmaceuticals products in natural surface waters and in the effluent sewage treatment plants have been reported since 1980s. More recently, these products have been detected in ground and drinking water. However, there is little information about the risks these drugs and their metabolites in the water, have, for the human health (Ferrando-Climentet al. , 2013).There are few published studies with detailed information about the significance of pharmaceuticals compounds in water for humans (Ferrando- Climentet al. , 2013). The major concern with genotoxic/carcinogenic pharmaceuticals compounds is a cancer risk, at any level of exposure because there is no threshold dose below which no carcinogenic effect may occur (Garcia-AC et al., 2011). The pharmaceutical compounds are excreted to wastewater and become potential water contaminants. Currently, very little is known about the presence and elimination process of cytostatic drugs in wastewater treatment plants. The lack of methods and knowledge about the specific risk of pharmaceutical products in aquatic environment may be consider a public health problem.
- Evaluation of antimicrobial activity in products containing Neem oilPublication . Fernandes, Sara; Barreiros, Luisa; Ferraz Oliveira, Rita; Prudêncio, Cristina; Vieira, Mónica; Santos, Nuno; Morgado, Joaquim; Cruz, AgostinhoNeem oil is obtained from seeds of Azadirachta indica, which present 30 to 50% (w/w) of oil per seed. Neem oil has been associated with a great diversity of beneficial properties, namely antimicrobial, anti-inflammatory and insecticide. Information concerning the antibacterial activity of Neem oil is scarce. Although the existing studies have demonstrated activity against both Gram+ and Gram- bacteria, the results are in some cases contradictory and do not include a significant number of organisms, namely organisms associated with skin infections.
- Chromatographic method for the simultaneous quantification of dapsone and clofazimine in nanoformulationsPublication . Machado, Sandia; Fernandes, Sara; Chaves, Luise L.; Lima, Sofia A. C.; Silva, Eduarda M. P.; Barreiros, Luisa; Reis, Salette; Segundo, Marcela A.The low bioavailability and nonspecific distribution of dapsone and clofazimine, commonly applied in combination for the treatment of leprosy, can produce toxic effects. Nanotechnological approaches enhance the delivery of these drugs. Therefore, a high-performance liquid chromatography method was developed for the simultaneous determination of dapsone and clofazimine loaded in nanoformulations for quality control purposes. Chromatographic separation was achieved on a reversed-phase Kinetex core-shell C18 column, followed by spectrophotometric detection at 280 nm. Considering the different physicochemical properties of dapsone and clofazimine, elution was performed in gradient mode using an aqueous acetate buffer (50 mmol/L, pH 4.8) and an increasing acetonitrile content from 27 to 63% v/v at a flow rate of 1.0 mL/min with retention times of 6.2 and 14.0 min, respectively. The method was validated according to the European Medicines Agency guideline and it was found to be specific, accurate (99.6-114.0%), and precise for intra- (RSD ≤ 1.8%) and interday assays (RSD ≤ 12.5%). Both drugs showed stability after 24 h at room temperature and over three freeze-thaw cycles with recoveries ≥86.2%. Low temperature (4°C) in the autosampler caused the precipitation of clofazimine and must be avoided. The validated method was successfully applied in the quantification of both drugs in nanoformulations.
- Total analysis system for the determination of uremic toxins in human plasma based on bead injection solid phase extraction hyphenated to mass spectrometryPublication . Fernandes, Sara; Barreiros, Luísa; Sampaio-Maia, Benedita; Miró, Manuel; Segundo, Marcela A.Indoxyl sulfate (INDS) and p-cresol sulfate (pCS) are two of the most relevant uremic toxins that are recognized to have an essential role in chronic kidney disease (CKD) progression and associated cardiovascular risk. Thus, it is crucial to accurately assess their circulating levels in the body. Aiming at establishing an analytical strategy for quantification of INDS and pCS in human plasma, an automatic on-line micro-solid-phase extraction (μSPE) procedure hyphenated to tandem mass spectrometry (MS/MS) detection without previous chromatographic separation was herein developed. The bead injection (BI) concept was used to implement the μSPE procedure in the lab-on-valve (LOV) format. After studying the extraction conditions, the anion-exchange OASIS WAX sorbent beads (10 mg) and 99% ACN–H2O (15:85, v/v)–1% (v/v) NH4OH were chosen as sorbent and eluent, respectively, as they provided the highest analyte recoveries. Subsequently, the μSPE-BI-LOV system was hyphenated on-line to a MS/MS detector and the full analytical cycle, comprising sample preparation and analytes detection, was completed in <20 min. The developed μSPE-BI-LOV-MS methodology presented good linearity (r2 > 0.999) for quantification of the target analytes at concentrations ranging from 18 to 360 μg mL−1 in plasma. LOQ values were 2 μg mL−1 for INDS and 7 μg mL−1 for pCS in plasma. Human plasma samples from healthy subjects and individuals with CKD were successfully analyzed using the developed approach. The proposed automatic methodology can be described as an eco-friendly strategy, with a favorable score of 0.64 after greenness evaluation using the AGREE metric.
- Drug-drug interactions and risk factors of interactions in oncologyPublication . Fernandes, Sara; Teixeira, S.; Ferraz Oliveira, RitaDrug-Drug interactions (DDI’s) are a frequent occurrence in clinical practice and in particular in oncology. Cancer patients are assumed as a risk group, mainly due to the high number of drugs related, as well as the changes inherent in the cancer context. In the context of cancer, the studies on DDI's in oncology are reduced in number, presenting incidences ranging from 12% to 63%, depending on the type of population study. Following the high morbidity and mortality that can be associated with DDI's, there is a need to conduct further study on this topic, in order to minimize the occurrence of dangerous DDI's and ensure the prescription and administration of effective and secure therapeutics. Identify and characterize the most commons DDI’s and identify possible risk factors involved in the occurrence of DDI's, in oncology. It was performed a literature review of articles published in several electronic databases (Pubmed, Ebsco and B-on), about DDI’s in the context of cancer patients, from the year 2005. After analysis of the articles obtained were considered seven articles, six articles on the occurrence of potential DDI’s and one study on the occurrence of real DDI’s, in oncology. It should be noted the reduced percentage of studies on real DDI's, where was verified that about 2% of the patients studied were exposed to DDI's. As regards to the potential DDI's, it is noteworthy the high number of DDI's detected and the high percentage of cancer patients exposed, both ambulatory context as in internment (about one-third of subjects in study). Regardless of the type of cancer patient studied, the drugs most referenced are anticonvulsant, antihypertensive and warfarin. The interactions detected were mainly pharmacokinetics and of moderate severity. As regards to risk factors were identified the age, the presence of comorbidities and the polypharmacy, the latter being described as the main factor for the occurrence of DDI's. In short, it was verified that DDI's in oncology require special attention, so the implementation of strategies allowing precocious detection are essential or even avoiding its occurrence. Besides clinical issues involved, DDI’s are associated to a major economic impact, so their complication becomes a higher cost to this patient’s treatment. The health professional is an essential agent preventing DDI's, to ensure the effectiveness of therapy and quality of life of patients.