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

UV SPECTROPHOTOMETRIC METHOD FOR QUANTITATIVE DETERMINATION OF BILASTINE USING EXPERIMENTAL DESIGN FOR ROBUSTNESS

Bilastine is a novel nonsedative H1-receptor antagonist, which may be used for the symptomatic treatment of chronic idiopathic urticaria (CU). This study describes the validation of an UV spectrophotometric method for quantitative determination of bilastine in tablets using 0.1 mol L-1 HCl as solvent. The method was specific, linear, precise, exact and robust at 210 nm, confirming that the method is fast and useful to the routine quality control of bilastine in tablets. The validate method was compared to liquid chromatography (HPLC), which was previously developed and validated to the same drug, and no significative difference between the methods using Student´s t test was found to bilastine quantitation.Bilastine is a novel nonsedative H1-receptor antagonist, which may be used for the symptomatic treatment of chronic idiopathic urticaria (CU). This study describes the validation of an UV spectrophotometric method for quantitative determination of bilastine in tablets using 0.1 mol L-1 HCl as solvent. The method was specific, linear, precise, exact and robust at 210 nm, confirming that the method is fast and useful to the routine quality control of bilastine in tablets. The validate method was compared to liquid chromatography (HPLC), which was previously developed and validated to the same drug, and no significative difference between the methods using Student´s t test was found to bilastine quantitation

Bilastine: stability-indicating a method using environmentally friendly by reversed-phase high-performance liquid chromatography (RP-HPLC)

This study describes the development and validation of a new environmentally friendly analytical method for the determination of bilastine in coated tablets and the evaluation of its capacity to be stability-indicating as well. The ecofriendly analytical method was validated by specificity, linearity, accuracy, precision and robustness by reversed-phase high-performance liquid chromatography (RP-HPLC) according to International Conference on Harmonization guidelines (ICH) and Association of Official Analytical Chemists (AOAC). Isocratic LC separation was achieved on a RP18 column using a mobile phase of sodium dihydrogen phosphate aqueous buffer solution adjusted to pH (6.0 ± 0.1) with o-phosphoric acid (85% v/v) and triethylamine (0,3% v/v) and ethanol (EtOH) in the following proportions (60:40 v/v), at a flow rate of 1.0 mL·min-1 at temperature-controlled at 30 °C. The analytical method showed selectivity, good recovery and precision (intra- and inter-day), robustness, and linear over a range from 5.0 to 50 μg·mL-1

Evaluation of the influence of fluoroquinolone chemical structure on stability: forced degradation and in silico studies

Fluoroquinolones are a known antibacterial class commonly used around the world. These compounds present relative stability and they may show some adverse effects according their distinct chemical structures. The chemical hydrolysis of five fluoroquinolones was studied using alkaline and photolytic degradation aiming to observe the differences in molecular reactivity. DFT/B3LYP-6.31G* was used to assist with understanding the chemical structure degradation. Gemifloxacin underwent degradation in alkaline medium. Gemifloxacin and danofloxacin showed more degradation perceptual indices in comparison with ciprofloxacin, enrofloxacin and norfloxacin in photolytic conditions. Some structural features were observed which may influence degradation, such as the presence of five member rings attached to the quinolone ring and the electrostatic positive charges, showed in maps of potential electrostatic charges. These measurements may be used in the design of effective and more stable fluoroquinolones as well as the investigation of degradation products from stress stability assays

Validation of an analytical method by high-performance liquid chromatography and microbiological assay, biological safety and in silico toxicity for danofloxacin

Danofloxacin is a veterinary fluoroquinolone used to treat respiratory and gastrointestinal diseases of birds, pigs and cattle. The literature reviewed shows some analytical methods to quantify this fluoroquinolone, but microbiological and biological safety studies are limited. The analytical methods were validated by the Official Codes. The LC-DAD method was developed and validated using an RP-18 column, mobile phase containing a mixture of 0.3% triethylamine (pH 3.0) and acetonitrile (85:15, v/v). The microbiological assay was performed by agar diffusion method (3 x 3) and Staphylococcus epidermidis as a microorganism test. Forced degradation studies were performed in both methods. The minimum inhibitory concentration (MIC) was performed by test microdilution and toxicity studies were evaluated using in silico study, cell proliferation, cell viability test, micronuclei and comet assay. LC and a microbiological assay proved linear, accurate, precise, and robust to quantify danofloxacin, but only the LC method showed selectivity to quantify the drug in the presence of its degradation products. These results demonstrate that the LC method is suitable for stability studies of danofloxacin, but a microbiological assay cannot be used to quantify the drug due to the biological activity of the photoproducts. Ex-vivo cytotoxicity and theoretical and experimental genotoxicity were also observed

Nitazoxanide: development and validation of analytical methods and stability study

A nitazoxanida é um novo antiparasitário de amplo espectro e pertence à classe dos nitrotiazóis. No Brasil, encontra-se disponível na forma de comprimidos revestidos e pó para suspensão oral, sob nome cormercial de Annita . A análise de fármacos é necessária em todas as fases do desenvolvimento farmacêutico e na manutenção da segurança e eficácia terapêutica dos produtos comercializados. Assim, o presente trabalho objetivou o desenvolvimento e validação de métodos para análise qualitativa e quantitativa da nitazoxanida nas formas farmacêuticas comerciais e a avaliação da estabilidade do fármaco em condições de degradação forçada, contemplando a determinação da cinética de fotodegradação e o isolamento, identificação e estudo da citotoxicidade do produto de degradação majoritário. As análises por espectrometria de massas (MS/MS), infravermelho (IV), ressonância magnética nuclear (RMN 1H e 13C) e calorimetria exploratória diferencial permitiram identificar a nitazoxanida utilizada como substância química de referência. Os métodos por cromatografia em camada delgada, espectrofotometria no ultravioleta (UV), cromatografia líquida de alta eficiência (CLAE) e eletroforese capilar (EC) foram utilizados para identificação do fármaco nas formas farmacêuticas. Os métodos quantitativos validados foram: UV, CLAE e EC. Todos cumpriram com os parâmetros descritos pelas guias de validação e não apresentaram diferença estatística significativa na determinação do fármaco. O estudo preliminar de estabilidade frente à degradação oxidativa, ácida, básica, térmica e fotolítica demonstrou que o fármaco é instável em todas as condições testadas, sendo que os meios oxidativo, alcalino e fotolítico foram os fatores de maior importância. A cinética de fotodegradação da nitazoxanida apresentou cinética de ordem zero para ambas as formas farmacêuticas. Em todas as condições de degradação testadas ocorreu a formação de um produto de degradação majoritário, chamado de PD1, o qual precipitou nas condições analíticas e foi isolado por filtração. O mesmo foi identificado por RMN 1H e 13C, EM/EM e IV como o derivado desacetilado da nitazoxanida, a tizoxanida. A avaliação preliminar da citotoxicidade indicou que o produto isolado apresenta maior toxicidade celular in vitro após 48 horas de incubação frente à células mononucleares, quando comparado à nitazoxanida. Os resultados obtidos neste trabalho demonstram a importância do aprofundamento dos estudos nesta área para garantir a segurança e eficácia terapêutica dos produtos farmacêuticos comercializados.Nitazoxanide is a new broad-spectrum antiparasitic drug and it belongs to the class of nitrothiazol. In Brazil, it is available as tablets and powder for oral suspension, under the cormercial name of Annita . Drug analysis is needed in all phases of pharmaceutical development and maintenance of marketed products safety and efficacy. Thus, the present study aimed the methods development and validation for qualitative and quantitative analysis of nitazoxanide in commercial pharmaceutical forms and evaluation of drug stability in forced degradation conditions, comprising the photodegradation kinetics determination and the isolation, identification and the cytotoxicity study of the major degradation product. The analysis by mass spectrometry (MS/MS), infrared (IR), nuclear magnetic resonance (1H and 13C NMR) and differential scanning calorimetry allows to identify the nitazoxanide chemical reference structure. The methods by thin layer chromatography, spectrophotometry (UV), high performance liquid chromatography (HPLC) and capillary electrophoresis (CE) were used to identify the drug in pharmaceutical formulations. Quantitative methods have been validated: UV, HPLC and CE. All methods met the criteria described by the validation guidelines and showed no significant statistically difference in the drug determination. The preliminary stability study of nitazoxanide under oxidative, acidic, basic, thermal and photolytic conditions showed that the drug is unstable in all tested conditions, and oxidative, alkaline and photolytic conditions are the factors of major importance. The photodegradation kinetics of nitazoxanide showed zero-order kinetics for both dosage forms. In all tested degradation conditions it was formed a majority degradation product, named PD1, which precipitated in the analytical conditions and it was isolated by filtration. The same product was identified by 1H and 13C NMR, MS/MS and IR as deacetylated derivative of nitazoxanide, the Tizoxanide. The preliminary citotoxicity evaluation indicated that the isolated product has a higher cellular toxicity in vitro after 48 hours of incubation, when compared to nitazoxanide. The results demonstrate the importance of this type of study to ensure the safety and efficacy of marketed pharmaceutical products