41 research outputs found
New aspects in the liquid chromatographic analysis of Capecitabine in samples of biological and non-biological origin // Нови аспекти в течнохроматографския анализ на Capecitabine в проби от биологичен и небиологичен произход
No full textThe treatment of malignancies is a serious challenge for the modern healthcare system. Evidence of this is the drastic increase in morbidity and mortality due to cancer globally (by 44% and 26%, respectively).
On the other hand, the survival rate of cancer patients receiving cytostatic treatment has increased by only 14% in the last decade. The reason for the unsatisfactory results is the lack of selective cytotoxic action, as well as the narrow therapeutic range of antineoplastics. There is a high incidence of drug-induced toxicity, which can be life-threatening, requiring discontinuation of treatment, as well as the administration of additional drugs. Therefore, nowadays, studies aimed at optimising cytostatic treatment play an essential role in the fight against neoplasms.
For more than half a century, the fluoropyrimidine class of cytostatics has been a cornerstone in treating malignancies such as colorectal cancer, breast cancer, stomach cancer, pancreatic, ovarian cancer, head and neck cancer. Their representative is the antineoplastic Capecitabine (CAP), rationally designed as an oral prodrug form of intravenous infusion of 5-Fluorouracil (5-FU). Its creation aims to achieve targeted antitumor action, increase cytostatic activity, and reduce the toxicity of the active substance to the body's healthy cells.
The present dissertation has a scientific-applied character. It includes research on problems concerning both intake and handling of fluoropyrimidine carbamate CAP. Its relevance is determined by the significant increase in the use of the prodrug and the ever-increasing incidence of cancer. The liquid chromatographic methods for the qualitative and quantitative determination of CAP reported in the scientific literature are analysed in detail.Лечението на злокачествени заболявания се явява сериозно предизвикателство за съвременната система на здравеопазване. Доказателство за това е драстичният ръст на заболяемостта и смъртността вследствие на рак в глобален мащаб (съответно с 44% и с 26 %).
От друга страна, през последното десетилетие преживяемостта на онкологично болните пациенти, приемащи цитостатично лечение, е повишена с едва 14 %. Причина за недостатъчно удовлетворителните резултати e липсата на селективно цитотоксично действие, както и тясната терапевтична ширина на антинеопластиците. Налице е висока честота на лекарство-индуцирана токсичност, която може да бъде животозастрашаваща, да налага преустановяване на лечението, а също и прием на допълнителни лекарства. Ето защо, в наши дни проучванията, насочени към оптимизиране цитостатичното лечение изпълняват важна функция в борбата срещу неоплазиите.
Повече от половин век флуоропиримидиновият клас цитостатици е крайъгълен камък в лечението на злокачествени заболявания, като колоректален карцином, рак на гърдата, рак на стомаха, рак на панкреаса, рак на яйчниците, карцином на главата и шията. Техен представител е антинеопластикът Capecitabine (CAP), рационално проектиран като орална пролекарствена форма на венозно вливания 5-Fluorouracil (5-FU). Със създаването му се цели постигане на насочено противотуморно действие, повишаване цитостатичната активност и редуциране на токсичността на активното вещество спрямо здравите клетки на организма.
Настоящият дисертационен труд има научно-приложен характер. Включва изследвания относно проблеми, касаещи както приема, така и работата с фуоропиримидиновия карбамат CAP. Актуалността ѝ се определя от значителния ръст в употребата на пролекарството и непрестанно увеличаващата се ракова заболяемост. Анализирани в детайли са съобщените в научната литература течнохроматографски методи за качествено и количествено определяне на CAP. Предложени са нови подходи за анализ на CAP, съобразени със съвременните световни здравни норми и потребности
Does modern chemical analysis allow the identification of passive cannabis smokers?
Full text linkCannabis continues to be the most widely used drug worldwide. This increases the risk of positive drug tests in individuals with a secondary exposure. For this reason, the aim of the present work was to clarify the possibilities of modern toxicochemical analysis to distinguish the biological samples of passive smokers of cannabis.The algorithm by which drug use is monitored today includes the sequential implementation of screening and evidentiary analytical methods. Through the former, possible drug users are filtered, and through the latter, the reliability of the obtained results is categorically confirmed.Due to its kinetic characteristics, the main psychoactive component of marijuana, Δ9-tetrahydrocannabinol (THC), is sometimes replaced as a target analyte by one of its metabolites. In urine, which is the most frequently studied type of biological matrix, it is practice to determine the amount of non-pharmacologically active 11-nor-9-carboxy-Δ9-tetrahydrocanbinol. It has been established that in passive smokers its concentrations do not exceed 50 ng/mL in drug screening and 15 ng/mL in confirmatory analysis. Alternatively, THC and/or its metabolites can be tested in blood, hair, saliva, and others.The analytical tools of the XXI century allow the identification of individuals exposed to the psychoactive agent THC in a passive way. This does not, however, negate the personal responsibility of each individual to avoid playing the role of a passive smoker
Possible reasons for the occurrence of false-negative results in urine drug screening
Full text linkIntroduction: Immunoassay screening of urine samples play a central role in the monitoring and fight against ever-increasing drug abuse. Thus, the aim of the present work was to clarify the reasons for deliberately or unintentionally causing of false-negative screening results.Materials and Methods: For the purpose of the study, an analysis of Google Scholar, PubMed, and Science Direct databases was conducted.Results: The exact number of false-negative results in the analytical practice cannot be precisely determined because of the impossible confirmation of each screening test. In this regard, the screening of drug abuse appears to be a huge challenge these days due to multiple reasons. On the one hand, it is necessary to take into account the physicochemical properties of sometimes an unknown analyte, as well as the physiological characteristics of each individual. On the other hand, the test antibodies available to date do not have the necessary specificity for absolutely all drugs, especially designer ones. At the same time, there is an unlimited access to information and products supporting the manipulation of urine samples, respectively the achievement of false-negative results. In response, analytical chemistry offers a variety of methods to address the problem of filtering out abusers.Conclusion: Because of their high throughput and low cost, immunoassay techniques continue to be a cornerstone of drug screening, whether for clinical or criminological purposes. However, the risk of false-negative results requires efforts to improve their specificity in parallel with the implementation of countermeasures against the manipulation of the biological samples
Research about the Possibility of Increasing the Bioavailability of Capecitabine
No full textIntroduction: Capecitabine is an antimetabolite that belongs to the fluoropyrimidine carbamate class. It is a chemotherapy medication used to treat breast, gastric and colorectal cancer. Inside the organism, this pro-drug is converted to the active 5-fluorouracil (5-FU) that causes cell injury via RNA- and DNA-related mechanisms. The conversion is a three-step process with the participation of the enzymes - carboxylesterase (CES), cytidine deaminase and thymidine phosphorylase that are present in healthy and tumor cells. This research, specifically, is dedicated to CES isozymes CES1A1 and CES2, which convert Capecitabine to 5`-deoxy-5-fluorocytidine (5`-DFCR).Materials and methods: To determine Capecitabine we have used: Thermo Scientific Dionex UltiMate 3000 Analytical LC System, VWD-3100 variable wavelength detector, Thermo Scientific™ Chromeleon™ 7.2 Chromatography Data System software. The chromatographic analysis was carried out by using a mobile phase of methanol: buffer (water with 1% formic acid) with a Thermo Scientific Accucore C18 (100 mm x 4.6 mm, 2.6μ) analytical column in gradient mode with UV detection at 310 nm.Results: Recently, the structure of the active centre of isozymes CES1A1 and CES2 has been successfully determined. This allows the exploration of new or already known substances with structural similarity. It is important to investigate such supplements that could assist in the treatment without increasing the risk of adverse effects. A sensitive, accurate and reliable method for the determination of Capecitabine in pharmaceutical dosage forms and in human plasma was developed using a RP-HPLC. The established LOD and LOQ values allow us to conduct monitoring of the bioavailability of Capecitabine after CES-inhibitors application.Conclusions: Based on the established relationship between structure and biological activity of known CES inhibitors new potential inhibitors with natural origin could be offered. Using the RP-HPLC allows us to research the pharmacokinetic parameters of Capecitabine after CES-inhibitors in further investigations
The role of resources centres in the construction of information literacy in romanian school system
No full textNon-fourni par l'auteureNot given by the author in time
Rolul centrelor de documentare şi informare ïn crearea unei culturi informaţionale în învăţămăntul preuniversitar romănesc
No full textNot given by the author in time.Non-fourni par l'auteur
Rolul centrelor de documentare şi informare ïn crearea unei culturi informaţionale în învăţămăntul preuniversitar romănesc
No full textNot given by the author in time.Non-fourni par l'auteur
Study of patients' compliance and attitudes for self-medication with antibiotic therapy
No full textIntroduction: Since the discovery of penicillin by Alexander Fleming in 1928, antibiotics have been used widely and successfully in the treatment of various infectious diseases. However, in recent years, it is in-creasingly common for bacteria to become resistant to one or more pharmaceutical substances and on multiple occasions, there have been numerous reports for multidrug resistant strains. Some of the explanations for this fact include over-prescription of antibiotics by general practitioners, poor compliance by patients, as well as self-medication.Aim: To collect information for the treatment habits of the Bulgarian city population, including evaluation of the level of their compliance and willingness to self-medicate.Materials and Methods: A specially designed online questionnaire was applied as well as face-to-face interviews with an identical paper-based questionnaire. The data were processed statistically. Results: A medium percent of the interviewed population reported use of an antibiotic agent in the last 12 months, and about 20 percent of those reported self-medication. In general, patients who had consulted a doctor and had acquired a prescription showed a high level of compliance. Medication was obtained mainly through a community pharmacy, and information on therapeutic effects and dosage regimen was provided primarily by a physician, followed by pharmacists, patient information leaflets and the Internet.Conclusions: The reported high compliance level suggests a good probability for positive therapeutic outcome, while self-medication can lead to side effects, poor therapeutic outcome, as well as development of resistant microorganisms. A larger and more comprehensive survey will provide deeper insight into patients’ treatment habits and can investigate the influence of various socio-economic factors in patients’ decision for self-medication
Green Tea: Antioxidant vs. Pro-Oxidant Activity
No full textGreen tea is one of the most consumed beverages globally. It is very popular due to its specific taste, energizing effect and some health benefits related mainly to the catechins content. Green tea catechins possess antioxidant, anticancer, anti-inflammatory and antimicrobial activity as well as reduce body weight. One of the major and well-studied effects of green tea catechins is their antioxidant effect. However, long-term administration of high doses of antioxidants may result in a pro-oxidant effect and promote cell damage. Therefore, beneficial effects of green tea are directly related to the administered dose of catechins. But it should be noted that consumption of large quantities of green tea beverages or administration of high doses of green tea catechins does not guarantee health benefits and may even lead to adverse effects. This review provides a comprehensive overview of the current knowledge of the antioxidant and pro-oxidant activity of green tea catechins as well as research gaps that require further investigation. In conclusion, despite green tea antioxidant potential, further research is needed to fully understand the benefits and risks associated with the consumption of green tea beverages as well as green tea catechins in different forms and doses
Green Tea: Current Knowledge and Issues
No full textGreen tea possesses antioxidant, anti-inflammatory, anticancer, and antimicrobial activities, reduces body weight, and slows down aging. These effects are primarily attributed to catechins contained in green tea leaves, particularly epigallocatechin-3-gallate. However, in humans, the realization of green tea’s beneficial effects is limited. In order to summarize and critically analyze the available scientific information about green tea’s health benefits and issues related to its use, we conducted an in-depth literature review in scientific databases. A number of in vitro studies reported that green tea catechins modulate various signaling pathways in cells, which is thought to underlie their beneficial effects. However, data on the effects of catechins in humans are scarce, which is partly due to their low stability and oral bioavailability. Furthermore, catechins may also participate in pharmacokinetic interactions when co-administered with certain drugs such as anticancer agents, drugs for cardiovascular diseases, immunosuppressors, etc. As a result, adverse drug reactions or therapy failure may occur. In conclusion, over the years, various approaches have been investigated to optimize catechin intake and to achieve beneficial effects in humans, but to date, the use of catechins for prophylaxis or disease treatment remains limited. Therefore, future studies regarding the possibilities of catechins administration are needed
