Efecto del ciprofibrato sobre el metabolismo del colesterol HDL y la capacidad antioxidante plasmática en el ratón / Effect of ciprofibrate on HDL cholesterol metabolism and plasma anti-oxidant capacity in mice

Antecedentes: Las dislipidemias, ya sea un aumento en los niveles de colesterol LDL y/o una disminución en las cifras de colesterol HDL, son muy relevantes para el desarrollo de la enfermedad cardiovascular ateroesclerótica, siendo el colesterol HDL bajo la dislipidemia más frecuente en la población chilena. Con respecto al colesterol HDL bajo y los tri -glicéridos elevados, los fibratos, agonistas del receptor nuclear PPAR-a que modula la transcripción de genes involucrados en el metabolismo de lípidos, representan una importante alternativa de manejo farmacológico de las dislipidemias. Sin embargo, estudios clínicos recientes no han sido concluyentes con respecto a su beneficio real sobre el control de la ateroesclerosis cuando se usan combinados con estatinas. Objetivo: Evaluar el impacto de la administración de fibratos sobre el metabolismo del colesterol HDL y la función antioxidante del plasma usando el ratón como modelo experimental. Metodología: Los ratones de la cepa C57BL/6 fueron tratados con ciprofibrato al 0,2% en dieta control durante 7 días. Luego del tratamiento, se analizaron los niveles de colesterol plasmático y triglicéridos, la expresión hepática de proteínas claves involucradas en el metabolismo de colesterol HDL, el contenido de colesterol hepático, la secreción de colesterol biliar y el daño oxidativo y la función antioxidante plasmática. Resultados: El tratamiento con ciprofibrato disminuyó significativamente los niveles de triglicéridos plasmáticos y la expresión hepática del receptor de HDL SR-BI, efecto que se correlacionó con un aumento en el tamaño de las partículas de HDL, pero no en los niveles de colesterol HDL. Además, el ciprofibrato disminuyó los niveles proteicos de los transportadores de colesterol ABCG1 y ABCG8, aunque no modificó ABCA1, en conjunto con una reducción del contenido hepático de colesterol y un aumento en la secreción de colesterol hacia la bilis. Finalmente, el uso de este hipolipemiante mejoró la función antioxidante del plasma, aunque se detectó un aumento en el daño nitrosativo de las proteínas plasmáticas. Conclusión: Este estudio ha permitido obtener nueva información sobre el efecto metabólico y funcional de la administración de fibratos en ratones, lo cual podría ayudar comprender los resultados de estudios clínicos recientes que han usado esta clase de hipolipemiantes en humanos.

Background: Increased serum levels of LDL cholesterol and/or decreased values of HDL cholesterol are very relevant for atherosclerotic cardiovascular disease. Low HDL cholesterol is the most prevalent dyslipidemia in the Chilean population. Regarding reduced HDL cholesterol and high triglyceride levels, fibrates, nuclear receptor PPAR-a agonists that modulate transcription of genes involved in lipid metabolism, represent an important alternative for pharmacological management of dyslipidemia. However, recent clinical studies have been inconclusive with respect to their real benefit on atherosclerosis when used in combination with statins. Aim: To evaluate the impact of fibrate administration on HDL cholesterol metabolism and antioxidant plasma functionality using the mouse as experimental model. Methodology: Using wild-type C57BL/6 mice, ciprofibrate was administered at 0.2% in chow diet for 7 days. After treatment, plasma cholesterol and triglycerides levels, hepatic expression of key proteins involved in HDL cholesterol metabolism, liver cholesterol content, biliary cholesterol secretion, and plasma oxidative damage and antioxidant function were analyzed. Results: Ciprofibrate treatment significantly decreased plasma triglycerides levels and hepatic HDL receptor SR-BI expression. This latter finding was associated with increased HDL particle size, without changes in HDL cholesterol levels. Furthermore, ci-profibrate decreased hepatic expression of cholesterol transporters ABCG1 and ABCG8, but not ABCA1, which correlated with reduced liver cholesterol content and increased biliary cholesterol secretion. Fina-lly, fibrate therapy improved plasma antioxidant func-tion, even though increased nitrosative plasma protein damage was detected. Conclusion: This study has provided new information on metabolic and functional effects derived from fibrate use in mice and it may help to better understand recent clinical findings using this lipid-lowering drug class in humans.

Stability-indicating liquid chromatographic and UV spectrophotometric methods for the quantification of ciprofibrate in capsules and tablets

This study describes the development and evaluation of stability-indicating liquid chromatographic (LC) and UV spectrophotometric methods for the quantification of ciprofibrate (CPF) in tablets and capsules. Isocratic LC separation was achieved on a RP18 column using a mobile phase of o-phosphoric acid (0.1% v/v), adjusted to pH 3.0 with triethylamine (10% v/v) and acetonitrile (35:65 v/v), with a flow rate of 1.0 mL min-1. Detection was achieved with a photodiode array detector at 233 nm. For the spectrophotometric analysis, ethanol and water were used as the solvent and a wavelength of 233 nm was selected for the detection. The methods were validated according to International Conference on Harmonization (ICH) guidelines for validating analytical procedures. Statistical analysis showed no significant difference between the results obtained by the two methods. The proposed methods were successfully applied to the CPF quality-control analysis of tablets and capsules.

Este estudo descreve o desenvolvimento e avaliação de método indicativo da estabilidade por cromatografia líquida (LC) e método por espectrofotometria UV para quantificação de ciprofibrato (CPF) em comprimidos e cápsulas. No método por cromatografia líquida as análises foram realizadas isocraticamente em coluna de fase reversa C18, utilizando fase móvel composta por ácido o-fosfórico (0.1% v/v) pH 3.0, ajustado com trietilamina (10% v/v), e acetonitrila (35:65 v/v), com fluxo de 1,0 mL min-1. A detecção foi realizada em detector de arranjo de diodos a 233 nm. Na análise espectrofotométrica, etanol e água foram utilizados como solventes e o comprimento de onda de 233 nm foi selecionado para a detecção do fármaco. Os métodos foram validados de acordo com as diretrizes do International Conference on Harmonization (ICH). A análise estatística não mostrou diferença significativa entre os resultados obtidos pelos dois métodos. Os métodos foram aplicados com sucesso para análises de controle de qualidade do ciprofibrato em comprimidos e cápsulas.

Estudo de bioequivalência entre duas formulações de ciprofibrato 100 mg comprimidos em voluntários sadios após administração de dose única / Bioequivalence study between two formulations of ciprofibrate 100 mg tablets in healthy volunteers after single dose administration

A comparação da biodisponibilidade de duas formulações de ciprofibrato 100 mg comprimidos (ciprofibrato 100 mg - Aché Laboratórios Farmacêuticos S/A, formulação teste, e Oroxadin® 100 mg - Sanofi-Aventis Farmacêutica Ltda., formulação referência) foi realizada por meio de um estudo de bioequivalência em 52 voluntários sadios. O estudo foi realizado através de um delineamento aberto, randomizado, em dose única, cruzado em dois períodos e com tempo de washout de nove semanas. As amostras de plasma foram obtidas durante um intervalo de tempo de 72 horas. As concentrações plasmáticas de ciprofibrato foram determinadas por cromatografia líquida de alta eficiência com detecção por espectrometria de massas (CLAE-MS/MS), com ionização por electrospray em modo positivo. Os parâmetros farmacocinéticos área sob a curva (ASC0-72), concentração plasmática máxima (Cmax) e tempo máximo (Tmax) foram obtidos a partir da curva de concentração plasmática do ciprofibrato versus tempo. As razões das médias geométricas com intervalo de confiança 90% após transformação logarítmica foram 89,43% (85,09% - 93,99%) para Cmax e 97,23% (94,73% - 99,79%) para ASC0-72. As formulações teste e referência são consideradas bioequivalentes se os intervalos com 90% de confiança para a média geométrica da razão teste/referência ficarem compreendidos na faixa de 80% a 125%. Dessa forma os comprimidos de ciprofibrato 100 mg testados (Aché Laboratórios Farmacêuticos S/A) foram bioequivalentes aos comprimidos de Oroxadin® 100 mg, de acordo com taxa e extenção de absorção.

Validation of a spectrophotometric method to determine ciprofibrate content in tablets / A validação de um método espectrofotométrico para determinar o conteúdo de ciprofibrato em comprimidos

Ciprofibrate is a drug indicated in cases of hypertriglyceridemia and mixed hyperlipidemia, but no monographs are available in official compendia for the analysis of this substance in tablets. The objective of this work was to develop and validate a spectrophotometric method for routine analysis of ciprofibrate in tablets. In this study, commercial and standard ciprofibrate were used, as well as placebo in absolute ethanol, analyzed by UV spectrophotometer. All tests followed the rules of Resolution RE-899, 2003. The results showed that the developed and validated method offers low cost, easy implementation, precision and accuracy, and may be included in the routine of quality control laboratories.

O ciprofibrato é um fármaco indicado em casos de hipertrigliceridemia e hiperlipidemia mista, mas não há monografias em compêndios oficiais para a análise desta substância em comprimidos. O objetivo deste trabalho é desenvolver e validar um método espectrofotométrico para análise de rotina de ciprofibrato em comprimidos. Neste estudo foram empregados ciprofibrato comercial, padrão e placebo em etanol absoluto, analisadas por espectrofotometria UV. Todos os testes seguiram as regras da Resolução RE- 899, 2003. Os resultados mostraram que o método desenvolvido e validado apresenta baixo custo, fácil implementação, precisão e exatidão e pode ser incluído em rotina de laboratórios de controle de qualidade.

Efficacy of Ciprofibrate Monotherapy in Patients with Type II and Type IV Hyperlipidemia

BACKGROUND: The ciprofibrate, 3rd generation fibrate derivative, is known as an effective hypolipidemic drug in both hypercholesterolemia and hypertriglyceridemia. We studied the efficacy and side effects of ciprofibrate dmonotherapy in patients with primary type II and type IV hyperlipidemia. METHOD: Patients who showed 12-hours fasting serum total cholesterol level more than 240mg% and/or serum triglyceride level more than 250mg% were enrolled to diet therapy. After 12 weeks of diet therapy serum lipid profiles were checked and the drug therapy was considered according to the above mentioned guidelines. The ciprofibrate 100mg p.o qd was administrated and the patients had regular follow-up every 6 weeks for 12 weeks. RESULTS: The total study population was 32 patients. Fifteen patients were type II hyperlipidemia and seventeen patients were type IV hyperlipidemia. The drug was well tolerated in all patients. There was mild gastrointestinal side effects in 9% of study patients but no patients discontinued ciprofibrate due to side effects. There was mild and transient serum CK elevation less than 3 times of baslines in 5(15%) patients. The LFT, serum uric acid, BUN and creatinine level did not show any significant changes during therapy. Serum total cholesterol and apolipoprotein B level in patients with type II hyperlipidemia showed significant reduction after 6week of therapy. The mean reduction was 25% and 32% respectively. Serum triglyceride level in patients with type IV hyperlipidemia decreased by 55%. The reduction of total cholesterol more than 25% could be achieved in 50% of type II hyperlipidemia and the reduction of triglyceride more than 25% could be achieved in 93% of type IV hyperlipidemia. CONCLUSION: The ciprofibrate is effective and sage hypolidipemic drug in patients with primary type II and type IV hyperlipidemia.