Photochemical stability of biologically active compounds: V. Photochemical degradation of primaquine in an aqueous medium

Kristensen, Solveig; Grislingaas, Anne-Lise; Greenhill, John V.; Skjetne, Tore; Karlsen, Jan; Tønnesen, Hanne

doi:10.1016/0378-5173(93)90070-v

Cited by 23 publications

(12 citation statements)

References 10 publications

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“…Os produtos de degradação fotoquímica da primaquina são potentes indutores de radicais livres 9 10 . Os produtos de degradação identificados para primaquina in vitro são diferentes dos metabólitos deste fármaco, mas há correlação da estabilidade in vitro e os efeitos adversos in vivo 10 . Ensaios preliminares realizados pelo Ministério da Saúde, por intermédio da Rede Amazônica de Vigilância às Drogas Antimaláricas (RAVREDA), sobre a eficácia de fármacos constantes no Manual de Terapêutica da Malária, mostram resistência dos parasitos aos medicamentos e sugerem à qualidade dos medicamentos empregados como um dos fatores determinantes 15 .…”

Section: Discussionunclassified

Perfil de dissolução in vitro de comprimidos de primaquina disponíveis para tratamento de malária no Brasil

Rodrigues

Watanabe

Ferraz

2008

Rev. Soc. Bras. Med. Trop.

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Até o início da década de 60, era comum que se considerasse um medicamento eficaz clinicamente apenas assegurando-se o controle de qualidade, que incluía somente o conhecimento das propriedades físicas e físico-químicas do fármaco. A ineficácia clínica e, em alguns casos, intoxicações graves, serviram de alerta para estudos mais profundos sobre os componentes da formulação, processos empregados e características físico-químicas dos fármacos 17 . Dentre as formas farmacêuticas de uso oral, as formas farmacêuticas sólidas -particularmente os comprimidos -têm merecido destaque pela possibilidade de apresentarem problemas de biodisponibilidade.Para obtenção do efeito terapêutico a partir de um medicamento na forma de comprimido, quando administrado por via oral, é necessário que o fármaco passe da forma de dosificação em que se encontra para outra em que seja diretamente absorvível. ABSTRACTThe clinical inefficacy of many medications has served to highlight the need for deeper studies on the formulation components, processes used and physicochemical characteristics of drugs. The objective of this study was to evaluate the in vitro release of primaquine phosphate from tablets available in Brazil for treating malaria, and the development of new formulations for conventional release. Although the primaquine phosphate tablets studied had been approved according to the criteria proposed by the United States Pharmacopoeia (2006) for the dissolution test, they did not present adequate dissolution performance characteristics, in that there was drug retention during the release process. The results indicate the existence of problems in the primaquine phosphate tablets analyzed, and it may suggest that this is one of the factors responsible for the appearance of parasite resistance.

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Section: Discussionunclassified

Perfil de dissolução in vitro de comprimidos de primaquina disponíveis para tratamento de malária no Brasil

Rodrigues

Watanabe

Ferraz

2008

Rev. Soc. Bras. Med. Trop.

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“…Excitation wavelength E° Reducion potential FEN Fenbufen k 1 First order rate constant k 2 Second order rate constant k obs Observed 1.…”

Section: Abbreviationsmentioning

confidence: 99%

“…The degradation was followed by HPLC and UV-vis spectrophotometry. The degradation of primaquine (40 μM) in D 2 O was compared to the analogue degradation in water, and the influence of molecular oxygen was investigated by flushing with N 2 -gas for 10 min. prior to irradiation.…”

Section: Photochemical Degradationmentioning

confidence: 99%

“…The sample cell (Spectrosil quartz) had an optical path length of 25 mm [19]. Radiation doses were measured using the thiocyanate actinometer where the absorption of (SCN) 2 •-formed by pulsing an air saturated aqueous solution of 10 mM KSCN is measured taking ε 500 (SCN) 2…”

Section: Pulse Radiolysismentioning

confidence: 99%

“…Primaquine is a photolabile compound, with a ground state absorption maximum at 350 nm and extension of the absorption spectrum towards 430 nm under physiological conditions. The drug decomposes photochemically into several degradation products at physiological pH, by oxygen dependent reaction mechanisms [2][3][4]. Primaquine forms an intramolecular hydrogen bond, which seems to be essential for chemical and biological properties, including photochemical stability and fluorescence.…”

Section: Introductionmentioning

confidence: 99%

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Photoreactivity of biologically active compounds. XIX: Excited states and free radicals from the antimalarial drug primaquine

Kristensen

Edge

Tønnesen

et al. 2009

Journal of Photochemistry and Photobiology B: Biology

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The formation and reactivity of excited states and free radicals from primaquine was studied in order to evaluate the primary photochemical reaction mechanisms. The excited primaquine triplet was not detected, but is likely to be formed with a short lifetime (< 50 ns) and with a triplet energy < 250 kJ/mol as the drug is an efficient quencher of the fenbufen triplet and the biphenyl triplet, and forms -is eliminated as a degradation pathway in the photochemical reactions. Impurities in the raw material and photochemical degradation products initiate photosensitized degradation of primaquine in deuterium oxide, prevented by addition of the 1 O 2 quencher sodium azide. Photosensitized degradation by formation of 1 O 2 is thus important for the initial photochemical decomposition of primaquine, which also proceeds by free radical reactions. Formation of PQH 2+

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Determination of quinacrine dihydrochloride dihydrate stability and characterization of its degradants

Espeau

Corvis

Guyon

et al. 2011

Journal of Pharmaceutical Sciences

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Photochemical stability of biologically active compounds: V. Photochemical degradation of primaquine in an aqueous medium

Cited by 23 publications

References 10 publications

Perfil de dissolução in vitro de comprimidos de primaquina disponíveis para tratamento de malária no Brasil

Perfil de dissolução in vitro de comprimidos de primaquina disponíveis para tratamento de malária no Brasil

Photoreactivity of biologically active compounds. XIX: Excited states and free radicals from the antimalarial drug primaquine

Determination of quinacrine dihydrochloride dihydrate stability and characterization of its degradants

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