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Witamina C w terapii przeciwnowotworowej? – przegląd danych klinicznych i przedklinicznych

100%

Regulska K., Litwiniuk M. M.

Farmacja Polska

2020

vol. 76

issue 4

222-236

The use of intravenous, high-dose vitamin C in cancer therapy has remained controversial for a long time. Despite this, it has been commonly administered for decades by complementary health care practitioners. This article reviews the existing clinical and pre-clinical data on the efficacy and safety of L-ascorbic acid in oncological diseases, with the emphasis on the following issues: 1) Does vitamin C demonstrate therapeutic efficacy? In which clinical situations? 2) What is the mechanism of vitamin C action? 3) Is the use of vitamin C in oncology safe? 4) What is the effect of vitamin C on other therapies used simultaneously? Based on the analysis of available literature, it has been concluded that although L-ascorbic acid exhibits a possible anticancer effect, as shown mainly by preclinical studies, the reliable clinical data justifying the introduction of vitamin C into conventional oncology has been lacking so far. In fact, the following issues still remain unknown: types of cancer that could be sensitive to high-dose vitamin C therapy, groups of patients that could benefit from such management, doses, routes of administration and pharmaceutical forms that could provide an optimal anticancer effect, the molecular mechanism of vitamin C anticancer action, the impact of vitamin C on the concurrently used therapies, including chemotherapy, impact of vitamin C on the quality of life of oncological patients. So far, the available clinical trials have not confirmed the positive reports from experimental studies. Therefore, it is suggested that patients intending to undrgo such treatment should be informed that there is no evidence to justify the anticancer efficacy of vitamin C infusions and that in certain populations (i.e. patients with deficiency of glucose 6-phosphate dehydrogenase, renal dysfunction or haemochromatosis) vitamin C infusions may cause serious adverse effects. However, there seems to be sufficient evidence to continue research on the role of vitamin C in cancer treatment.

Stosowanie witaminy C w postaci dożylnych infuzji w bardzo wysokich dawkach w ramach alternatywnej terapii nowotworów od wielu lat pozostaje przedmiotem rozlicznych kontrowersji. Jednakże z uwagi na dość powszechny charakter takich praktyk w ramach niniejszego artykułu dokonano przeglądu dostępnych danych klinicznych i przedklinicznych w tym zakresie, próbując znaleźć odpowiedź na pytania dotyczące skuteczności i bezpieczeństwa kwasu L-askorbinowego w leczeniu chorób onkologicznych. Rozważano między innymi: 1) Czy witamina C wykazuje skuteczność terapeutyczną, na podstawie jakich dowodów i w jakich sytuacjach klinicznych? 2) Jaki jest mechanizm działania witaminy C? 3) Czy stosowanie witaminy C w onkologii jest bezpieczne? 4) Jaki jest wpływ witaminy C na inne, jednocześnie stosowane terapie? Na podstawie analizy dostępnego piśmiennictwa stwierdzono, że choć pewien efekt przeciwnowotworowy tego związku jest możliwy, na co wskazują głównie badania przedkliniczne, to jednak współczesna medycyna wciąż nie dysponuje wiarygodnymi danymi klinicznymi, które mogłyby uzasadnić wprowadzenie witaminy C do konwencjonalnej terapii w onkologii.

Kinetics and mechanism of solid state imidapril hydrochloride degradation and its degradation impurities identification

100%

Regulska K., Stanisz B.

Open Chemistry

2013

vol. 11

issue 5

754-762

A detailed stability testing of solid state imidapril hydrochloride (IMD) was performed and its degradation products were identified. The analysis was conducted according to ICH guidelines Q1A(R2). Pure IMD samples were exposed to stress conditions of elevated temperature and relative humidity (T = 363 K, RH = 76.4%) in order to accelerate degradation. The regular loss of IMD content with time, and the formation of two degradation impurities were observed. The appropriate reaction rate constants k (for IMD degradation and for the formation of product I and II) were calculated using Prout-Tompkins equation. The obtained degradation products were separated and identified by means of LC-MS technique. Based on the obtained m/z values, the masses and the structures of the formed degradation impurities were established. Also IMD degradation scheme was constructed. It was demonstrated that under the applied analytical conditions, IMD degradation follows an autocatalytic reaction model with the rate constant k = (4.764 ± 0.34)×10 −6 s −1 and with the parallel formation of two degradation products: imidaprilat and the diketopiperazine derivative. The obtained experimental results are in agreement with IMD degradation pathways proposed theoretically. [...]

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1 Farmacja Polska

1 Open Chemistry

1 2020

1 2013

2 Regulska K.

1 Litwiniuk M. M.

1 Stanisz B.

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Witamina C w terapii przeciwnowotworowej? – przegląd danych klinicznych i przedklinicznych

Kinetics and mechanism of solid state imidapril hydrochloride degradation and its degradation impurities identification