Combinação dose fixa de hidroclorotiazida (12, 5 mg) e valsartana (160 mg): Desenvolvimento de metodologia de dissolução in vitro e in silico para avaliar os perfis de dissolução dos produtos comercializados no Brasil e Peru / Fixed dose combination of hydrochlorothiazide (12. 5 mg) and valsartan (160 mg): Development of in vitro and in silico dissolution methodology to evaluate the dissolution profiles of products marketed in Brazil and Peru

Hidroclorothiazida (HTZ) e valsartana (VAL) são fármacos pouco solúveis em meio aquoso e pertencem às classes IV e II do Sistema de Classificação Biofarmacêutica (SCB), respectivamente. O objetivo deste trabalho foi desenvolver um método para avaliar o perfil de dissolução de formas farmacêuticas sólidas de dose fixa combinada contendo HTZ (12,5 mg) e VAL (160 mg) usando ferramentas in silico para avaliar os perfis de dissolução de produtos comercializados no Brasil e Peru. O presente trabalho foi dividido em 4 capítulos. No Capítulo I, foi determinada a solubilidade da HTZ e VAL pelo método shake-flask e potenciométrico, no qual foi possível demonstrar que existe correlação entre ambos os métodos e que HTZ e VAL são solúveis em tampão fosfato pH 6,8. No Capítulo II, um método cromatográfico em HPLC foi desenvolvido com base em Quality by Design (QbD), com auxílio do software Fusion®, no qual foi estabelecido uma zona de confiança dos parâmetros, que garantiu a robustez do método. O Capítulo III descreve o desenvolvimento de um método de dissolução utilizando ferramenta in silico (DDDplus®) na qual foi definido um delineamento experimental do tipo fatorial completo 33 usando como fatores a formulação, utilização de âncora e velocidade de agitação. Para os ensaios de dissolução in vitro, foi proposto um outro delineamento fatorial 3(3-1) com o intuito de obter as constantes de calibração das simulações in silico. Através de uma análise estatística das eficiências de dissolução obtidas nas simulações, foram avaliados os efeitos e as interações entre os fatores. Assim, as condições finais do método de dissolução estabelecidas foram: 900 mL de tampão fosfato pH 6,8 como meio de dissolução, 75 rpm de velocidade de agitação, e utilização de âncora para evitar a flutuação das formulações. O método desenvolvido foi empregado, no contexto do Capítulo IV, para avaliar o perfil de dissolução dos produtos contendo HTZ e VAL comercializados no Brasil e no Peru. Por análise multivariada, a eficiência de dissolução (ED), tempo médio de dissolução (MDT) e as porcentagens de dissolução de 5 até 60 minutos foram utilizadas para agrupar as formulações em grupos distintos. Embora os perfis de dissolução mostrem similaridade entre todas as formulações avaliadas, o produto referência se destacou por apresentar uma maior ED comparado com as outras formulações, devido à maior liberação nos primeiros 5 minutos de ensaio. Concluiu-se que o método proposto, além de garantir a liberação total de HTZ e VAL a partir das formulações, possui adequado poder discriminativo

Hydrochlorothiazide (HTZ) and valsartan (VAL) are poorly soluble drugs in aqueous medium and belong to classes IV and II of the Biopharmaceutical Classification System (BCS), respectively. The objective of this study was to develop a dissolution method to evaluate the dissolution profile of solid pharmaceutical forms of combined dose containing HTZ (12.5 mg) and VAL (160 mg) using in silico tools to evaluate the dissolution profiles of products sold in Brazil and Peru. The present study was divided into four chapters. In Chapter I, the HTZ and VAL solubility were determined by the shake-flask and potentiometric methods, in which it was possible to demonstrate that there is a correlation between both methods and that HTZ and VAL are soluble in pH 6.8 phosphate buffer. In Chapter II, a chromatographic method in HPLC was developed based on Quality by Design (QbD), using the Fusion® software, in which a zone of confidence of the parameters was established, which ensured the robustness of the method. Chapter III presents the development of a dissolution method using in silico (DDDplusTM) as a tool, in which an experimental design of the complete factorial type 33 was defined using as factors: the formulation, use of sinker and agitation speed. For in vitro dissolution assays, another factor design 3(3-1) was proposed to obtain the calibration constants of the in silico simulations. Through a statistical analysis of the dissolution efficiencies obtained in the simulations, the effects and interactions between the factors were evaluated. Thus, the final conditions of the dissolution method established were: 900 mL of pH 6.8 phosphate buffer as a dissolution medium, 75 rpm of stirring speed, and use of sinker to avoid the fluctuation of the formulations. The method developed was used, in the context of Chapter IV, to evaluate the dissolution profile of HTZ and VAL products marketed in Brazil and Peru. By multivariate analysis, the dissolution efficiency (ED), mean dissolution time (MDT) and the dissolution percentages from 5 to 60 minutes were used to group the formulations in different groups. Although the dissolution profiles show a similarity between all the evaluated formulations, the reference product stood out for presenting a higher ED compared to the other formulations, due to the higher release in the first 5 minutes of the test. It was concluded that the proposed method, besides guaranteeing the total release of HTZ and VAL from the formulations, has adequate discriminatory capacity

An HPLC-UV method for the measurement of permeability of marker drugs in the Caco-2 cell assay

The Caco-2 cell line has been used as a model to predict the in vitro permeability of the human intestinal barrier. The predictive potential of the assay relies on an appropriate in-house validation of the method. The objective of the present study was to develop a single HPLC-UV method for the identification and quantitation of marker drugs and to determine the suitability of the Caco-2 cell permeability assay. A simple chromatographic method was developed for the simultaneous determination of both passively (propranolol, carbamazepine, acyclovir, and hydrochlorothiazide) and actively transported drugs (vinblastine and verapamil). Separation was achieved on a C18 column with step-gradient elution (acetonitrile and aqueous solution of ammonium acetate, pH 3.0) at a flow rate of 1.0 mL/min and UV detection at 275 nm during the total run time of 35 min. The method was validated and found to be specific, linear, precise, and accurate. This chromatographic system can be readily used on a routine basis and its utilization can be extended to other permeability models. The results obtained in the Caco-2 bi-directional transport experiments confirmed the validity of the assay, given that high and low permeability profiles were identified, and P-glycoprotein functionality was established.

Metanálise de estudos de bioequivalência: a intercambiabilidade de genéricos e similares que contêm hidroclorotiazida é possível, mas não àqueles com maleato de enalapril / Meta-analysis for bioequivalence studies: interchangeability of generic drugs and similar containing hydrochlorothiazide is possible but not with enalapril maleate

INTRODUÇÃO: O programa de genéricos no Brasil propiciou maior acesso da população a medicamentos. Para garantir a intercambiabilidade entre medicamentos referência e genérico ou similar, é necessário que eles sejam bioequivalentes. Com o crescimento do número de medicamentos genéricos, é comum que pacientes o substituam por outro genérico ou similar. Contudo, essa troca pode não garantir a manutenção da bioequivalência. Para avaliar a segurança na intercambiabilidade entre diferentes genéricos e similares com hidroclorotiazida e maleato de enalapril, foi realizada metanálise de vários estudos de bioequivalência que utilizaram esses medicamentos. MÉTODOS: Foram utilizados dados provenientes de estudos de bioequivalência de genéricos e similares registrados pela Agência Nacional de Vigilância Sanitária (Anvisa). A compatibilidade dos dados de cada um dos estudos foi analisada, e a determinação de um intervalo de confiança para as diferenças entre as médias dos parâmetros farmacocinéticos, área sob a curva (ASC) e concentração plasmática máxima (Cmáx ), foi feita para cada estudo por meio da metanálise. RESULTADOS: A intercambiabilidade entre as combinações dos três produtos com Hidroclorotiazida foi confirmada com base nos intervalos de confiança obtidos. Para os medicamentos com maleato de enalapril, a intercambiabilidade não foi confirmada em 50 por cento das comparações estudadas dos produtos. CONCLUSÃO: A intercambiabilidade foi comprovada entre os três produtos com hidroclorotiazida. No entanto, para o maleato de enalapril, metade dos produtos estudados não é intercambiável, uma vez que não contempla os intervalos preconizados pelos testes de bioequivalência; portanto, a resposta farmacocinética e, por conseguinte, a efetividade do medicamento podem ser alteradas.

INTRODUCTION: The generic drugs program provided a better population's access to medicines. To ensure interchangeability between a brand-name and generic or similar drugs is necessary that they are bioequivalent. With the growing number of generic drugs, it is common for patients to replace a generic to another or one similar. However, this exchange can not guarantee the maintenance of bioequivalence. To evaluate the safety interchangeability between different generic and similar drugs with hydrochlorothiazide and enalapril maleate, a meta-analysis was carried out with several bioequivalence studies with these drugs. METHODS: Data from bioequivalence of generic and similar drugs approved by the National Health Surveillance Agency (Anvisa) (drug regulatory agency in Brazil) were used. The compatibility of data from each study was analyzed and the determination of a confidence interval for the differences between the means of pharmacokinetic parameters, area under the curve (ASC0-t) and maximum plasma concentration (Cmax), was made for each study by meta-analysis. RESULTS: The interchangeability between the combinations of the three products with hydrochlorothiazide was confirmed based on the obtained confidence intervals. For the drugs studied with enalapril maleate interchangeability has not been confirmed for 50 percent of the product comparisons. CONCLUSION: The exchange was established between the three products with hydrochlorothiazide. However, for the enalapril maleate half of the products studied are not interchangeable, considering they do not match the established intervals for bioequivalence tests, so the pharmacokinetics behavior and thus the effectiveness of the product may be changed.

Simultaneous determination of irbesartan and hydrochiorothiazide in human plasma by high performance liquid chromatography and its pharmacokinetic application

Development of a simple, rapid and routine assay for the combination lrbesartan Hydrochlorothiazide [IB/HCTZ] for the investigation of their pharmacokinetic parameters in human plasma and bioequivalence study of LB I UCT [300/12.5mg] tablets manufactured locally [Test] and originally [Reference]. After extraction of [IB.HCTZ] from plasma, it was chromatographed with mobile phase consisting of phosphate buffer: acetonitrile: methanol [65:25:10] at flow rate of 1 ml/min and detected at wavelength of 272 nm. The pharmacokinetic study was conducted in a 2 X 2 crossover design involving 24 volunteers. The criteria used to assess bioequivalence of the two products were AUC[0-t], AUC[0-infinity], C[max], and t[max]. The described method for analysis showed that the recoveries of LB I HCTZ from plasma were 99.63%and 100.793% the limit of detection were 0.015 micro g/ml and 1.5 ng/ml respectively and the regression analysis for the drug concentrations indicated excellent linearity[r>0.999] for both. Statistical analysis [ANOVA] of the measured parameters showed that there was no significant difference between the two products. The HPLC method presented is direct, simple. reproducible, sensitive and linear for the determination of lB/HCT in human plasma and is adequate for its clinical pharmacokinetic studies. besides, the Test was found to be biocquivalent to the Reference and both products can be considered interchangeable in medical practice