Enhancing oral bioavailability of an antifungal thiazolylhydrazone derivative: Development and characterization of a self-emulsifying drug delivery system.

RN104 (2-[2-(cyclohexylmethylene)hydrazinyl)]-4-phenylthiazole) is a thiazolylhydrazone derivative with prominent antifungal activity. This work aimed to develop a self-emulsifying drug delivery system (SEDDS) loaded with RN104 to improve its biopharmaceutical properties and enhance its oral bioavailability. Medium chain triglycerides, sorbitan monooleate, and polysorbate 80 were selected as components for the SEDDS formulation based on solubility determination and a pseudo-ternary phase diagram. The formulation was optimized using the central composite design in response surface methodology. The optimized condition consisted of medium chain triglycerides, sorbitan monooleate, and polysorbate 80 in a mass ratio of 65.5:23.0:11.5, achieving maximum drug loading (10 mg/mL) and minimum particle size (118.4 ± 0.7 nm). The developed RN104-SEDDS was fully characterized using dynamic light scattering, in vitro release studies, stability assessments, polarized light microscopy, and transmission electron microscopy. In vivo pharmacokinetic studies in mice demonstrated that RN104-SEDDS significantly improved oral bioavailability compared to free RN104 (the relative bioavailability was 2133 %). These results clearly indicated the successful application of SEDDS to improve the pharmacokinetic profile and to enhance the oral bioavailability of RN104, substantiating its potential as a promising antifungal drug candidate.

Discovery of Lead 2-Thiazolylhydrazones with Broad-Spectrum and Potent Antifungal Activity.

Opportunistic fungal infections represent a global health problem, mainly for immunocompromised individuals. New therapeutical options are needed since several fungal strains show resistance to clinically available antifungal agents. 2-Thiazolylhydrazones are well-known as potent compounds against Candida and Cryptococcus species. A scaffold-focused drug design using machine-learning models was established to optimize the 2-thiazolylhydrazone skeleton and obtain novel compounds with higher potency, better solubility in water, and enhanced absorption. Twenty-nine novel compounds were obtained and most showed low micromolar MIC values against different species of Candida and Cryptococcus spp., including Candida auris, an emerging multidrug-resistant yeast. Among the synthesized compounds, 2-thiazolylhydrazone 28 (MIC value ranging from 0.8 to 52.17 µM) was selected for further studies: cytotoxicity evaluation, permeability study in Caco-2 cell model, and in vivo efficacy against Cryptococcus neoformans in an invertebrate infection model. All results obtained indicate the great potential of 28 as a novel antifungal agent.

Avaliação da bioequivalência entre duas formulações de rivaroxabana ­ 20 mg comprimido revestido ­ administradas em jejum e pós-prandial em voluntários sadios / Evaluation of bioequivalence between two rivaroxaban formulations ­ coated tablet 20 mg ­ administered under fasting and fed conditions in healthy volunteers

Objetivo: O objetivo deste trabalho foi avaliar a bioequivalência entre duas formulações de rivaroxabana 20 mg comprimido revestido, sendo a formulação teste produzida por Sanofi Medley, Brasil e a formulação referência (Xarelto®) comercializada por Bayer S/A. Métodos: Os estudos foram conduzidos em voluntários sadios de ambos os sexos e as formulações foram administradas em dose única, sob o estado de jejum e pós-prandial. Cada estudo foi conduzido de maneira independente, sendo ambos do tipo aberto, randomizado e com intervalo (washout) de sete dias entre os períodos. O estudo em jejum foi realizado em quatro períodos, com 48 voluntários, enquanto o pós-prandial foi realizado em dois períodos, com 36 voluntários. Resultados: Na administração em jejum, a razão entre a média geométrica da formulação teste e referência (T/R) de Cmáx foi de 100,77%, com intervalo de confiança de 90% (IC 90%) de 94,24% a 107,76%. Para ASC0-t, a razão T/R foi de 100,65%, com IC 90% de 96,13% a 105,39%. Na administração pós-prandial, a razão T/R de Cmáx foi de 110,63%, com IC 90% de 102,39% a 119,54%. Para ASC0-t, a razão T/R foi de 104,65%, com IC 90% de 98,44% a 109,12%. Conclusões: As formulações teste e referência foram consideradas estatisticamente bioequivalentes em ambas as condições de administração, de acordo com os critérios exigidos pela Agência Nacional de Vigilância Sanitária (Anvisa). A formulação teste foi registrada na Anvisa e disponibilizada para comercialização, contribuindo, assim, para a ampliação da disponibilidade do tratamento para doenças tromboembólicas e para a redução de custos ao paciente e ao Sistema Único de Saúde.

Objective: The objective of the present study was to evaluate the bioequivalence between two formulations of rivaroxaban 20 mg coated tablet, the test formulation being manufactured by Sanofi Medley, Brazil and the reference formulation (Xarelto® ) commercialized by Bayer S/A. Methods: The studies were conducted in healthy volunteers of both sexes and the formulations were administered in a single dose, under fasting and fed conditions. Each study was conducted independently, both being open-label, randomized and with a seven-day interval (washout) between periods. The fasting study was carried out in four periods, with 48 volunteers, while the fed study was carried out in two periods, with 36 volunteers. Results: In the fasting administration, the ratio between.

Electrochemical evidence of nitrate release from the nitrooxy compound 4-((nitrooxy) methyl)-3-nitrobenzoic acid and its antinociceptive and anti-inflammatory activities in mice.

Considering the many biological activities of nitric oxide (NO), some lines of research focused on the modulation of these activities through the provision of this mediator by designing and synthesizing compounds coupled with an NO donor group. Thus, the objectives of the present study were to carry out an electrochemical investigation of the nitrooxy compound 4-((nitrooxy) methyl)-3-nitrobenzoic acid (1) and evaluate its activities and putative mechanisms in experimental models of pain and inflammation. Voltammetric studies performed in aprotic medium (mimetic of membranes) showed important electrochemical reduction mechanisms: nitroaromatic reduction, self-protonation, and finally reductive elimination, which leads to nitrate release. Systemic administration of the nitrooxy compound (1) inhibited the nociceptive response induced by heat and the tactile hypersensitivity and paw edema induced by carrageenan in mice. The activities in the models of inflammatory pain and edema were associated with reduced neutrophil recruitment and production of inflammatory cytokines, such as interleukin (IL)-1ß, IL-6, tumor necrosis factor-α and CXCL-1, and increased production of IL-10. Concluding, electrochemical analysis revealed unequivocally that electron transfer at the nitro group of the nitrooxy compound (1) results in the cleavage of the organic nitrate, potentially resulting in the generation of NO. This electrochemical mechanism may be compared to a biochemical electron-transfer mediated nitrate release that, by appropriate in vivo bioreduction (enzymatic or not) would lead to NO production. Compound (1) exhibits activities in models of inflammatory pain and edema that may be due to reduced recruitment of neutrophils and production of inflammatory cytokines and increased production of IL-10. These results reinforce the interest in the investigation of NO donor compounds as candidates for analgesic and anti-inflammatory drugs.

Rapid Simultaneous Separation of Four Oral Antidiabetic Drugs and Quantitative Determination of Glibenclamide Using Conventional and Fused-Core Silica Columns.

Diabetes mellitus is a chronic disease with high and growing prevalence worldwide. Therefore, the development of fast and efficient methods for the QC of antidiabetic drugs is of fundamental importance. Two ultra-fast methods, using a conventional (C18 100 × 2.1 mm, 5 µm fully porous particle) column or a fused-core (C18 100 × 2.1 mm, 2.7 µm fused-core particle) column, were developed for the simultaneous determination of four antidiabetic drugs (chlorpropamide, glibenclamide, gliclazide, and glimepiride). The developed methods were compared in terms of efficiency, speed of analysis, resolution, and peak symmetry. Both methods were validated with respect to selectivity, system suitability, linearity, precision, accuracy, LOD, LOQ, and robustness, using glibenclamide as model. Conventional and fused-core methods were shown to be appropriate for the determination of glibenclamide in tablets; however, the fused-core column presented higher efficiency, detectability, and resolution. Also, it enabled faster analysis, with separation of the four drugs in less than 1 min.

Development and validation of an HPLC method for the simultaneous determination of artesunate and mefloquine hydrochloride in fixed-dose combination tablets

The present study developed and validated an HPLC method for the simultaneous determination of artesunate (AS) and mefloquine hydrochloride (MQ) in fixed-dose combination tablets, according to ICH guidelines. The chromatographic separation was carried out on an XBridge C18 (250 x 4.6 mm i.d., 5 µm particle size, Waters) analytical column. The mobile phase included a 0.05 M monobasic potassium phosphate buffer (pH adjusted to 3.0 with phosphoric acid) and acetonitrile (50 + 50, v/v). The flow rate was 1.0 mL/min, and the run time was 13 minutes. A dual-wavelength approach was employed: AS detection was performed at 210 nm and MQ was detected at 283 nm, using a diode array detector. Stability of sample solutions was evaluated for 8 hours after preparation, during which time the solutions remained stable. Youden's test was employed to evaluate robustness. The method proved to be linear (r²>0.99), precise (RSD<2.0%), accurate, selective, and robust, proving to be appropriate for routine drug quality control analysis.

Um método por cromatografia a líquido de alta eficiência para a determinação simultânea de artesunato (AS) e cloridrato de mefloquina (MQ) em comprimidos em dose fixa combinada foi desenvolvido e validado, de acordo com as normas do ICH. A separação cromatográfica foi realizada com uma coluna analítica XBridge C18 (250 x 4,6 mm d.i., partículas de 5 µm, Waters). A fase móvel foi constituída de tampão fosfato monobásico de potássio 0,05 M (pH ajustado para 3,0 com ácido fosfórico) e acetonitrila (50 + 50, v/v). O fluxo da fase móvel foi de 1,0 mL/min e o tempo de corrida foi de 13 minutos. Utilizaram-se dois comprimentos de onda: a detecção do AS foi realizada em 210 nm e a de MQ foi realizada em 283 nm, utilizando-se um detector de arranjo de diodos. A estabilidade das soluções padrão e amostra foi avaliada por 8 horas após sua preparação e as soluções permaneceram estáveis nesse período. O teste de Youden foi empregado para a avaliação da robustez do método. O método se mostrou linear (r²>0,99), preciso (DPR<2,0%), exato, seletivo e robusto, sendo adequado para análises rotineiras de controle de qualidade dos medicamentos.

Comparação de cromatografia líquida de alta eficiência e titulação em meio não aquoso para quantificação de alprazolam em cápsulas manipuladas / Comparison of high performance liquid chromatography and non-aqueous titration for the quantitation of alprazolam in compounded capsules

O objetivo pretendido com o presente trabalho foi avaliar a adequabilidade e viabilidade de dois métodos analíticos para quantificação de alprazolam em cápsulas manipuladas: cromatografia líquida de alta eficiência (CLAE) e titulação em meio não aquoso. A quantificação de alprazolam por CLAE fase normal foi realizada em coluna de sílica (30 x 4,6 mm) e fase móvel composta por acetonitrila, clorofórmio, butanol, água e ácido acético glacial (85:8:5:2:0,05). No método titulométrico, as amostras foram dissolvidas em mistura de ácido acético glacial e anidrido acético (3:2) e tituladas com ácido perclórico 0,1 M até o segundo ponto de inflexão. O teor médio de alprazolam obtido por CLAE foi 94,61%, demonstrando a adequabilidade do método proposto. Já as análises por titulação apresentaram teores equivalentes a 128,87% e 91,49% do valor rotulado, devido a interferências detectadas pela presença de excipientes da formulação. A adaptação e o desenvolvimento de métodos analíticos simples e viáveis são de extrema importância para avaliar e garantir a qualidade de medicamentos manipulados, de acordo com as exigências da legislação vigente.

The aim of this study was to assess the suitability and viability of two analytical methods for the quantitation of alprazolam in compounded capsules: high performance liquid chromatography (HPLC) and non-aqueous titration. Quantitation by normal phase HPLC was performed with a silica column (30 x 4.6 mm) and a mobile phase composed of acetonitrile, chloroform, butyl alcohol, water and glacial acetic acid (85:8:5:2:0.05). In the titration method, samples were dissolved in a mixture of glacial acetic acid and acetic anhydride (3:2) and titrated potentiometrically with 0.1 M perchloric acid until the second inflection point. The mean content of alprazolam obtained by HPLC was 94.61% of the label value, showing the suitability of the proposed method. On the other hand, the titration analysis returned contents equivalent to 128.87% and 91.49% of the label value, owing to interference caused by the presence of formulation excipients. The adaptation and development of simple and viable analytical methods are extremely important, in order to assay and ensure the quality of compounded formulations, according to the requirements of the current legislation.

Development and validation of an HPLC method for mefloquine hydrochloride determination in tablet dosage form.

A simple HPLC method for determination of mefloquine hydrochloride in tablets was developed and validated. The separation was carried out on an Xterra RP18 (250 x 4.6 mm id, 5 pm particle size) analytical column. The mobile phase was 0.05 M monobasic potassium phosphate buffer (pH 3.5)-methanol (40 + 60, v/v). The flow rate and wavelength were set to 1 mL/min and 283 nm, respectively. The method was specific for mefloquine hydrochloride in the presence of hydrolytic, oxidative, and photolytic degradation products. It was also linear, precise, accurate, and robust, being suitable for routine QC analyses and stability studies. The developed HPLC method was compared to a previously described spectrophotometric method.

Simultaneous quantitation of levodopa and 3-O-methyldopa in human plasma by HPLC-ESI-MS/MS: application for a pharmacokinetic study with a levodopa/benserazide formulation.

A sensitive and simple method was developed for the quantitation of levodopa and its metabolite 3-O-methyldopa, in human plasma, after oral administration of tablet formulations containing levodopa (200 mg) and benserazide (50 mg). The analytes were extracted by a protein precipitation procedure, using carbidopa as an internal standard. A mobile phase consisting of 0.2% formic acid and acetonitrile (94:6, v/v) was used and chromatographic separation was achieved using ACE C(18) column (50 mm×4.6 mm i.d.; 5 µm particle size). Selected reaction monitoring was performed using the fragmentation transitions m/z 198→m/z 107, m/z 212→m/z 166 and m/z 227→m/z 181 for levodopa, 3-O-methyldopa and carbidopa, respectively. Calibration curves were constructed over the range 50.0-6000.0 ng/mL for levodopa and 25.0-4000.0 ng/mL for 3-O-methyldopa. The method shown to be specific, precise, accurate and provided recovery rates higher than 85% for all analytes. No matrix effect was detected in the samples. The validated method was applied in a pharmacokinetic study with a levodopa/benserazide tablet formulation in healthy volunteers.

Quantitation of artemether in pharmaceutical raw material and injections by high performance liquid chromatography / Quantificação de artemether a matéria-prima farmacêutica e injeções por cromatografia líquida de alto desempenho

The quantitation of artemether in both pharmaceutical raw material and injections was carried out by high performance liquid chromatography (HPLC) with ultraviolet detection. A Zorbax C18 column (150 x 4.6 mm; 5 μm), at 30 ºC, and a mobile phase composed of acetonitrile and water (70:30), at a flow rate of 1ml/min, were used. The detection wavelength was 216 nm and the injection volume was 20 μL. The method proved to be linear (r²=0.9999), precise (RSD < 20 percent for intra-day and inter-day precision), accurate and selective regarding possible impurities and excipients of the samples. The detection and quantitation limits were 8 μg/mL and 25 μg/mL, respectively. The artemether content obtained in the raw material analysis was 99.26 percent and in the injections, 102.08 percent. The optimized and validated method may be successfully employed to perform routine quality control analyses.

A quantificação de artemeter em matéria-prima farmacêutica e solução injetável foi realizada por cromatografia líquida de alta eficiência (CLAE) com detecção na região do ultravioleta. Empregou-se coluna Zorbax C18 (150 x 4.6 mm; 5 μm), mantida a 30 ºC, e fase móvel composta por acetonitrila e água (70:30), com fluxo de 1 ml/min. A detecção foi realizada a 216 nm, e o volume de injeção foi 20 μl. O método se mostrou linear (r²=0,9999), preciso (DPR < 2,0 por cento para precisão intra-dia e inter-dias) e seletivo em relação a possíveis impurezas e excipientes das amostras. Os limites de detecção e quantificação obtidos foram 8 μg/mL e 25 μg/mL, respectivamente. O teor médio de artemeter obtido na análise da matéria-prima farmacêutica foi 99,26 por cento e na solução injetável, 102,08 por cento. O método otimizado e validado pode ser utilizado com sucesso para análises rotineiras em controle de qualidade.

Determination of ketoconazole in capsules by high-performance liquid chromatography and microbiological assay.

The development and validation of an HPLC-UV method and a microbiological assay were performed for the analysis of ketoconazole in capsule formulations. The bioassay was developed using a specific agar diffusion technique with the strain of Candida albicans ATCC 18804 as the test organism. The effect of the mobile phase pH in the range of 2.5-7.5 on the retention and tailing factors of the ketoconazole peak was analyzed in the chromatography method and a pH value of 4.5 was considered to be adequate. A prospective validation of both methods showed adequate linearity (r2 > 0.99 for the two methods), precision, (RSD = 2.42% for intraday and 2.69% for interday precision for bioassay; RSD = 0.74% for intraday and 0.66% for interday precision for HPLC-UV), and accuracy (mean recoveries were 103 +/- 1.0% for bioassay and 99 +/- 1.0% for HPLC-UV). Student's t-test revealed no significant difference between the results obtained by the two methods (P < 0.05). The contents found for three capsule samples showed a strong correlation, as attested by Pearson's coefficient value (r = 0.9998), which also evidenced the concordance between the studied methodologies.

Robustness evaluation of the chromatographic method for the quantitation of lumefantrine using youden's test / Avaliação da robustez do método cromatográfico para quantificação de lumefantrina utilizando o teste de youden

Youden's test is a reliable method to evaluate the robustness of analytical methods, by means of an experiment design which involves seven analytical parameters combined in eight tests. In the present study, we assessed the robustness of a chromatographic method to quantify lumefantrine in raw material samples, using Youden's test. Hence, it was possible to determine the effect of each analytical parameter in the final analysis results. Youden's test showed to be a simple and feasible procedure to evaluate the robustness of chromatographic methods.

O teste de Youden constitui um método confiável para avaliação da robustez de métodos analíticos, por meio de um delineamento que envolve sete parâmetros analíticos combinados em oito experimentos. No presente estudo, a robustez de um método cromatográfico para quantificação de lumefantrina em matéria-prima farmacêutica foi avaliada utilizando-se o teste de Youden. Assim, foi possível determinar o efeito de cada parâmetro analítico nos resultados finais das análises. O teste de Youden se mostrou um procedimento simples e confiável para a avaliação da robustez de métodos cromatográficos.

Simultaneous determination of artemether and lumefantrine in fixed dose combination tablets by HPLC with UV detection.

This paper describes the development and validation of a HPLC-UV method (210 nm) for the simultaneous quantitation of artemether and lumefantrine in fixed dose combination tablets. The method showed to be linear (r(2)>0.99), precise (R.S.D.<2.0%), accurate (recovery of 101.07% for artemether and 101.58% for lumefantrine), specific and robust. Four batches of artemether-lumefantrine tablets were assayed by the validated method. The artemether contents in the tablets varied from 98.61% to 103.35%, while lumefantrine contents were 97.92-100.48%.

Determinação de daidzeína, genisteína e gliciteína em cápsulas de isoflavonas por cromatografia em camada delgada (CCD) e cromatografia líquida de alta eficiência (CLAE) / Determination of daidzein, genistein and glycitein in isoflavone capsules by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC)

A utilização de produtos naturais e suplementos contendo extratos secos de isoflavonas aumentou na última década, devido, principalmente, aos efeitos benéficos atribuídos a estes compostos no alívio dos sintomas da menopausa. Genisteína, daidzeína e gliciteína são as agliconas mais abundantes nos extratos de soja, ocorrendo também como glicosídeos. Tendo em vista seus usos, não existe ainda na literatura uma definição da quantidade mínima de cada uma das agliconas que os extratos ou cápsulas de isoflavonas devem ter, e também não existe um método oficial para o controle de qualidade dos mesmos. O presente trabalho apresenta um método por CCD para análise qualitativa das três agliconas e de seus glicosídeos em extratos e cápsulas de isoflavonas, antes e após hidrólise ácida. A análise quantitativa das cápsulas de isoflavonas, realizada por cromatografia líquida de alta eficiência (CLAE), revelou grandes variações nos teores das três agliconas, após hidrólise ácida. Os teores variaram da seguinte forma, nos 18 lotes de cápsulas avaliados: daidzeína (13,34 a 76,20 mg/cápsula), genisteína (0,61 a 27,18 mg/cápsula) e gliciteína (0,49 a 8,80 mg/cápsula).

The use of herbal products and supplements based on isoflavone dry extracts has increased considerably in the last decade, mainly due to beneficial effects to relief of the menopausal symptoms credited to those compounds. Genistein, daidzein and glycitein are the most abundant isoflavone aglycones found in soy extract, where they also occur as glycosides. Concerning their uses, there is neither standardization regarding the minimum content of each aglycone in the extracts or capsules, nor an official method to the quality control of these products. The present work presents a TLC method for qualitative analysis of the three aglycones and their glycosides in extracts and capsules of isoflavones, before and after acid hydrolysis. The quantitative analysis of the isoflavone capsules, carried out by high performance liquid chromatography (HPLC), showed high variation in the content of the three aglycones, after acid hydrolysis. The contents varied in the following way, in the 18 batches of evaluated capsules: daidzein (13.34 to 76.20 mg/capsule), genistein (0.61 to 27.18 mg/capsule) and glycitein (0.49 to 8.80 mg/capsule).

Development and validation of a RP-HPLC method for quantification of isoflavone aglycones in hydrolyzed soy dry extracts.

Isoflavones are widely used as an alternative treatment to hormone replacement therapy and also for prevention of several chronic diseases, including cancers. Genistein, daidzein and glycitein are the most abundant isoflavone aglycones found in soy extracts, where they also occur as glycosides. This paper describes the development and validation of an isocratic reversed-phase HPLC (RP-HPLC) method for the analysis of isoflavone aglycones, released after acid hydrolysis of soy dry extracts, used as pharmaceutical raw material. The quantification was carried out in a C(18) endcapped column, using a mobile phase composed of 0.1% acetic acid and methanol (52:48), at a flow rate of 1.0 ml/min and diode array detection (DAD) at 254 nm. The method showed to be linear (r(2)>0.99), precise (R.S.D.<2%), accurate (recovery of 98.88% for daidzein and 98.12% for genistein), robust and specific.