Novel Eco-Friendly Stability Indicating Capillary Zone Electrophoresis Method for Determination of Aripiprazole in Tablet Dosage form: DoE Directed Optimization, Development and Method Validation.

In this work, a novel environment-friendly stability indicating capillary zone electrophoresis (CZE) method has been developed and validated for assaying the aripiprazole (ARP) in tablet dosage form. The separation of ARP from its degradation products and internal standard was achieved using a fused silica capillary column (30.2 cm x 75 µm ID), a background electrolyte containing 6 mmol L-1 ammonium formate buffer (pH 3) with 5% methanol under a potential of 15 kV and detection at 214 nm. The stability indicating ability of the method was investigated by analyzing ARP after being subjected to acidic, alkaline, thermal, photolytic, and oxidative stress conditions, according to ICH guidelines. Design of experiments was used during forced degradation and method optimization. Oxidation was the main degradation pathway among those evaluated. The drug was separated from its oxidative degradation products in less than 4 min. CZE method was linear between 60 - 140 µg mL-1, R2 = 0.9980, precise (intra-day 0.88% and inter-day 1.30%). The average recovery was 100.93 ± 0.77%. This is the first method in the literature for quantification of ARP in the presence of its related degradation products with high separation efficiency, low operation cost and minimum solvent consumption. This method could be helpful in the routine quality control analysis in the pharmaceutical industries with least harmful effect on the environment. CZE is considered an eco-friendly alternative of conventionally HPLC methods.

Stability-indicating method development for quantification of bromopride, its impurities, and degradation products by ultra-high performance liquid chromatography applying Analytical Quality by Design principles.

A comprehensive forced degradation study for bromopride was carried out in accordance with International Conference on Harmonization (ICH) recommendations followed by the identification and prospecting of the major degradation products. The analytical quality by design (AQbD) concepts were used to develop a stability-indicating method for bromopride and five organic impurities quantitation by ultra-high performance liquid chromatography with UV detection (UHPLC-UV). Two screenings and one optimization design were performed, including a Monte Carlo simulation to assess the Method Operable Design Region (MODR). The AQbD approach provided a high degree of method understanding in a very short period of time, less than two weeks, and the validated MODR provided information on robust analytical conditions contributing to the assignment of suitable control strategies.

Luliconazole: Stability-indicating LC method, structural elucidation of major degradation product by HRMS and in silico studies / Luliconazol: método por LC indicativo de estabilidad, elucidación estructural del producto de degradación mayoritario por HRMS y estudios in silico / Luliconazol: método LC indicativo de estabilidade, elucidação estrutural do principal produto de degradação por HRMS e estudos in sílico

SUMMARY Aim: A new stability-indicating liquid chromatography method was developed and validated for the quantitative determination of luliconazole. Materials and methods: Preliminary forced degradation study demonstrated an additional peak of the degradation product at the same retention time to the drug, due to this, the method was developed optimizing the chromatographic conditions to provide sufficient peak resolution (R ≥ 2). The experimental design was evaluated to assess the robustness and the best chromatographic conditions to be used for the validation. Methodology: Luliconazole solutions were exposed to various stress conditions to evaluate the method indication stability, in which the degradation product (DP-1) formed was isolated, identified, and evaluated in silico to predict degradation pathway and toxicity. The procedure was validated by robustness, selectivity, linearity, precision, and accuracy. Liquid chromatography was performed in a Phenomenex® RP-18 column with a mixture of acetonitrile and 0.3% (v/v) triethylamine solution as a mobile phase in isocratic elution. Results and conclusions: The method demonstrated robustness, good recovery, precision, linear response over a range from 5.0 to 40.0 μg.mL-1- and to be stability indicating. The alkaline stress condition resulted in the formation of DP-1. HRMS studies identified this product as an hydroxyacetamide derivative, and in silico studies did not show toxic potential.

RESUMEN Objetivo: Un nuevo método indicativo de estabilidad por cromatografía líquida fue desarrollado y validado para la determinación cuantitativa de luliconazol. Materiales y métodos: Estudios preliminares de degradación forzada demostraron un pico adicional en el mismo tiempo de retención del fármaco. El método desarrollado para optimizar las condiciones cromatográicas proporcionó una adecuada resolución (R ≥ 2). El diseño experimental fue evaluado para verificar su robustez y la mejor condición cromatográica para validación. Metodología: Las soluciones de luliconazol fueron expuestas a diferentes condiciones de estrés para evaluar la indicación de estabilidad del método, el aislamiento del producto de degradación formado (DP-1), su identificación y análisis in silico para predecir su ruta de degradación y toxicidad. El procedimiento se validó por robustez, selectividad, linealidad, precisión y exactitud. Las condiciones cromatográficas incluyeron una columna Phenomenex® RP-18, como fase móvil una mezcla de acetonitrilo y solución 0,3% (v/v) de trietilamina en elución isocrática. Resultados y conclusiones: El método mostró ser robusto, con buena recuperación, precisión, respuesta lineal en el rango de 5,0 a 40,0 μg.mL-1 e indicativo de la estabilidad. La condición de estrés alcalina resultó en la formación de DP-1. Estudios por HRMS identificaron este producto como un derivado hidroxiacetamida y los estudios in silico no mostraron potencial de toxicidad.

RESUMO Objetivo: Um novo método indicativo de estabilidade por cromatograia líquida foi desenvolvido e validado para a determinação quantitativa de luliconazol. Materiais e métodos: Estudos preliminares de degradação forçada demonstraram um pico adicional no mesmo tempo de retenção do medicamento. O método desenvolvido para otimizar as condições cromatográficas proporcionou resolução adequada (R ≥ 2). O delineamento experimental foi avaliado para verificar sua robustez e a melhor condição cromatográica para validação. Metodologia: Soluções de luliconazol foram expostas a diferentes condições de estresse para avaliar a indicação da estabilidade do método, o isolamento do produto de degradação formado (DP-1), sua identificação e análise in silico para predizer sua rota de degradação e toxicidade. O procedimento foi validado quanto à robustez, seletividade, linearidade, precisão e exatidão. As condições cromatográficas incluíram uma coluna Phenomenex® RP-18, como fase móvel uma mistura de acetonitrila e solução de trietilamina 0,3% (v/v) em eluição isocrática. Resultados e conclusões: O método mostrou-se robusto, com boa recuperação, precisão, resposta linear na faixa de 5,0 a 40,0 μg.mL-1 e indicativo de estabilidade. A condição de estresse alcalino resultou na formação de DP-1. Os estudos da HRMS identificaram este produto como um derivado da hidroxiacetamida e os estudos in silico não mostraram nenhum potencial de toxicidade.

Stability-indicating method for the novel antifungal compound RI76: Characterization and in vitro antifungal activity of its active degradation product.

RI76 is a novel 2-thiazolylhydrazone compound with reported antifungal activity. In preclinical drug development, it is fundamental to know the impurity profile and to understand degradation mechanisms of the molecule. In our study, RI76 was subjected to forced degradation conditions, and a stability-indicating HPLC-DAD method was developed and validated. Separation was carried out on a C18 column (150 × 4.6 mm i.d., 5 µm) maintained at 40°C using a 1 mL/min flow rate of 2 mM ammonium acetate with 0.1% formic acid (pH 3.0) and acetonitrile in gradient mode. The method was linear in the range of 0.7-91 µg/mL for RI76 and 0.7-25 µg/mL for its degradation product PD76. The formation of a major degradation product was quickly observed when RI76 was in aqueous solution. The chemical structure of this product, named PD76, was proposed based on LC-UV-MS experiments, synthesized in-house, and confirmed by NMR spectroscopy and chromatographic analysis. In vitro antifungal activity assays demonstrated that this resultant product shows a promising activity against clinically important Candida and Cryptococcus strains, matching or surpassing the activity of its precursor and of well-established antifungal drugs.

Comparative stability of arbutin in Arctostaphylos uva-ursi by a new comprehensive stability-indicating HPLC method.

INTRODUCTION: Arbutin is a phenol glucoside found in high concentrations in bearberry leaves and associated with the antimicrobial activity of the plant. Hydroquinone can also be found in leaves or be formed by degradation of arbutin. Lengthy exposure to free hydroquinone is associated with induction of toxicity in different organs. OBJECTIVE: To develop and validate a stability-indicating method by high-performance liquid chromatography diode array detector (HPLC-DAD) for simultaneous quantification of arbutin and hydroquinone in bearberry leaves and perform a comprehensive forced degradation study comparing synthetic arbutin and the arbutin in bearberry leaves. METHODS: Separation was performed using a C18 column, mobile phase with water-methanol (95:5), flow rate 1.0 mL/min and detection at 280 nm. Bearberry leaves were assayed and a forced degradation study of arbutin was performed in different conditions. RESULTS: The method complied with all required validation parameters. Contents varied from 1.19 to 4.15% (w/w) of arbutin and from 0.022 to 0.604% (w/w) of hydroquinone. Synthetic arbutin was susceptible to acid hydrolysis and oxidative degradation, forming hydroquinone as the main degradation product. The same study using bearberry leaves showed that constituents of the plant matrix may act as antioxidants, reducing the oxidative degradation of arbutin, however acid hydrolysis of arbutin occurred in higher intensity. CONCLUSION: Analysis of bearberry leaves evidenced high variation in arbutin and hydroquinone levels, demonstrating the need for standardisation and control. The stability profiles of synthetic arbutin and the arbutin in bearberry leaves were considerably different and the results may be useful for determining the most appropriate conditions for extraction and production of bearberry-based formulations.

Stability-indicating HPLC-DAD method for the simultaneous determination of fluoroquinolone in combination with a non-steroidal anti-inflammatory drug in pharmaceutical formulation

We developed and validated a stability-indicating assay method for the simultaneous determination of enrofloxacin and piroxicam in combination and in the presence of degradation products. Reverse-phase high-performance liquid chromatography analyses were carried out on a Vertisep C18 column and acetonitrile-water (48:52 v/v, pH 3.0) mobile phase with a 1.00 mL min−1 flow rate. The efficient chromatographic separation of these drugs and their forced degradation products was achieved in less than 5min with a peak purity match factor higher than 950. The method used showed linearity in the concentration ranges of 0.25 to 16.0 µg mL−1 for enrofloxacin (r = 0.9997) and 0.125 to 8.0 µg mL−1 for piroxicam (r = 0.9999) as well as precision (relative standard deviation lower than 2%), accuracy (mean recovery 100 ± 2%), and robustness, according to ICH (International Conference on Harmonization) and AOAC (Association of Official Analytical Chemists) guidelines. This method can simultaneously determine the combination of these drugs in a veterinary formulation and separate the drug peaks from their forced degradation products. Additionally, its optimized chromatographic conditions can contribute to the quality control of this formulation in pharmaceutical manufacturing plants and minimize waste from the organic solvent.

Stability and degradation products of imipenem applying high-resolution mass spectrometry: An analytical study focused on solutions for infusion.

Carbapenems show recognized instability in aqueous solutions; therefore some care must be taken in their handling and preparation and their use in the hospital environment. The stability and degradation products of imipenem were investigated from conditions that simulate its clinical use. For this, a simple stability-indicating method by HPLC-DAD was validated with a focus on the quantitation of drug concentration remaining from infusion solutions (sodium chloride 0.9% and glucose 5%). The degradation products formed were identified by high-resolution mass spectrometry (ESI-Q-TOF-MS/MS), with detection of the [M + H]+ ions at m/z 318 (DP-1), m/z 599 (DP-2) and m/z 658 (DP-3). The most probable elemental compositions were obtained with a high degree of confidence, where the error between the masses observed and calculated was 1.25 ppm for DP-1, -0.33 ppm for DP-2 and 1.82 ppm for DP-3. The DP-1 degradation product resulted from cleavage of the ß-lactam ring; DP-2 corresponded to the drug dimer; and DP-3 was generated from the interaction between imipenem and cilastatin. The proposed method provides a safe and reliable alternative for the quantitation of imipenem, and the stability data obtained by ESI-Q-TOF help in understanding the drug behavior under the conditions of clinical use.

Development and validation of a stability indicating HPLC method to determine diltiazem hydrochloride in tablets and compounded capsules

ABSTRACT A stability indicating HPLC method to determine diltiazem hydrochloride (DTZ) in tablets and compounded capsules was developed and validated according to Brazilian and the International Conference on Harmonization (ICH) guidelines. The separation was carried out on a Purospher Star® C18 (150 x 4.6 mm i.d., 5 µm particle size, Merck Millipore) analytical column. The mobile phase consisted of a 0.05% (v/v) trifluoroacetic acid aqueous solution and a 0.05% trifluoroacetic acid methanolic solution (44:56, v/v). The flow rate was 1.0 mL.min-1 with a run time of 14 minutes. The detection of DTZ and degradation products (DP) was performed at 240 nm, using a diode array detector. The method proved to be linear, precise, accurate, selective, and robust, and was adequate for stability studies and routine quality control analyses of DTZ in tablets and compounded capsules.

A bioanalytical HPLC method for coumestrol quantification in skin permeation tests followed by UPLC-QTOF/HDMS stability-indicating method for identification of degradation products.

Coumestrol is present in several species of the Fabaceae family widely distributed in plants. The estrogenic and antioxidant activities of this molecule show its potential as skin anti-aging agent. These characteristics reveal the interest in developing analytical methodology for permeation studies, as well as to know the stability of coumestrol identifying the major degradation products. Thus, the present study was designed, first, to develop and validate a versatile liquid chromatography (HPLC) method to quantify coumestrol in a hydrogel formulation in different porcine skin layers (stratum corneum, epidermis, and dermis) in permeation tests. In the stability-indicating test coumestrol samples were exposed to stress conditions: temperature, UVC light, oxidative, acid and alkaline media. The degradation products, as well as the constituents extracted from the hydrogel, adhesive tape or skin were not eluted in the retention time of the coumestrol. Hence, the HPLC method showed to be versatile, specific, accurate, precise and robust showing excellent performance for quantifying coumestrol in complex matrices involving skin permeation studies. Coumestrol recovery from porcine ear skin was found to be in the range of 97.07-107.28 µg/mL; the intra-day precision (repeatability) and intermediate precision (inter-day precision), respectively lower than 4.71% and 2.09%. The analysis using ultra-performance liquid chromatography coupled to a quadrupole time-of-flight high definition mass spectrometry detector (UPLC-QTOF/HDMS) suggest the MS fragmentation patterns and the chemical structure of the main degradation products. These results represent new and relevant findings for the development of coumestrol pharmaceutical and cosmetic products.

Desarrollo y validación de un método analítico indicativo de estabilidad por HPLC para la cuantificación de Rosuvastatina Cálcica / Development and validation of a stability indicating analytical HPLC method for the quantification of Rosuvastatin Calcium

En este trabajo, fue desarrollado y validado un método indicador de estabilidad por cromatografía líquida, para ser aplicado al estudio cinético de Rosuvastatina Cálcica en diferentes valores de pH y temperatura. Las condiciones cromatográficas seleccionadas fueron: columna C18, 50 x 4.6 mm y 3,5 µm de tamaño de partícula; fase móvil MeOH: Agua-0.1%TFA, temperatura de la columna de la columna 25 ° C, y velocidad de flujo 1 mL/min. El método validado presentó una adecuada repetibilidad y precisión intermedia y una recuperación superior al 98%. Por otra parte, el método fue lineal en el rango de 10 a 150 ppm. En condiciones ácidas, fueron identificados tres posibles productos de degradación como: Rosuvastatina Lactona, Rosuvastatina Anti-isómero y Rosuvastatina Lactona Anti-isómero y en condiciones de degradación con la luz se identificaron dos posibles productos mayoritarios. El método validado puede ser empleado en estudios de estabilidad y de degradación cinética del fármaco.

In this work, a liquid chromatography stability-indicating method was development and validated to be applied at study the hydrolytic behavior of Rosuvastatin Calcium in different pH values and temperatures. The selected chromatographic conditions were a column C18 50 x 4.6 mm and 3.5 µm. The mobile phase was Methanol: Water-1%TFA; 25°C column temperature and flow rate 1 mL/min. The validation method exhibited an adequate repeatability and intermediate precision and a recovery higher than 98%. Furthermore, the method was lineal in range of 10 to 150 ppm. Under acidic conditions, three degradation products possible were identified as Rosuvastatin lactone, Rosuvastatin anti-isomer and Rosuvastatin lactone anti-isomer, with light were identified two major decomposition products. The validated method can be used in the stability studies and drug degradation kinetics.

Desenvolvimento de metodologias indicativas de estabilidade para medicamentos que atuam no diabetes mellitus tipo II / Development of stability indicating methods for drugs that are used in diabetes mellitus 2

O diabetes mellitus (DM) é uma síndrome na qual o metabolismo de hidratos de carbono, gorduras e proteínas está alterado, por falta de secreção de insulina ou por diminuição da sensibilidade tissular a este hormônio. O DM pode ser do tipo I, também denominado diabetes mellitus insulinodependente (DMID), caracterizado pela falta de secreção da insulina, e do tipo II, também denominado diabetes mellitus não insulinodependente (DMNID), caracterizado pela menor sensibilidade dos tecidos efetores às ações metabólicas da insulina. Embora ainda não haja cura definitiva, há vários tratamentos disponíveis que proporcionam qualidade de vida para o paciente portador, como a administração de hipoglicemiantes orais. Nesta pesquisa, objetivou-se desenvolver métodos indicativos de estabilidade para a glibenclamida e o cloridrato de metformina. Assim, foram desenvolvidos métodos de rastreamento ortogonais utilizando a cromatografia líquida de alta eficiência (HPLC) e a eletroforese capilar (CE), metodologias que foram desafiadas com os estudos da degradação forçada. Realizou-se, também, a identificação do principal produto de degradação da glibenclamida utilizando a cromatografia líquida acoplada à espectrometria de massa (LC-MS). O método por HPLC teve o melhor desempenho no monitoramento dos produtos de degradação da glibenclamida, apresentando boa linearidade nas concentrações entre 0,210 e 0,360 mg/mL; com coeficiente de correlação maior de 0,99. A precisão calculada como desvio padrão relativo (DPR) foi menor de 3%, exatidão do método comprovada mediante teste de recuperação, obtendo-se valores de 100±3,0%. No teste de especificidade, foram detectados três potenciais produtos de degradação, com os seguintes tempos de retenção relativos (TRR) de 0,33; 0,46 e 0,83. O método CZE teve o melhor desempenho no monitoramento dos produtos de degradação do cloridrato de metformina, apresentando boa linearidade nas concentrações entre 0,210 e 0,360 mg/mL, com coeficiente de...

Diabetes mellitus (DM) is a syndrome which alters the metabolism of carbohydrates, fats and proteins by lack of insulin secretion or a decrease in tissue sensitivity to insulin. Type 1 DM is also known as insulin-dependent diabetes mellitus is characterized by lack of insulin secretion. The second type of diabetes known as Type II, also called non-insulin dependent, is characterized by the reduced sensitivity of target tissues to the metabolic actions of insulin. Although there is no definitive cure, there are several treatments available that provide quality of life for the patient how treatment with oral hypoglycemic agents. This study had as objective to developed stability-indicating methods for glibenclamide and metformin hydrochloride. Thus, the techniques used in this study involved high performance liquid chromatography (HPLC) and capillary electrophoresis (CE), and both were challenged with forced degradation studies. The identification of degradation products of glibenclamide was also performed, utilizing the mass spectrometry (MS) technique. However, the HPLC technique had the best performance for monitoring the degradation products of glibenclamide, which showed a good linearity in concentrations between 0.210 - 0.360 mg/ml, with a correlation coefficient greater than 0.99. The precision was calculated as a relative standard deviation (RSD) which was less than 3%; the accuracy of the method calculated as the percent recovery was obtained with the following values: 100 ± 3.0%. On the specificity were detected three potential products of degradation utilizing forced degradation, with the following relative retention times (RRT) 0.33, 0.46 and 0.83. The CZE method had the best performance to monitoring the degradation products of metformin hydrochloride, which showed good linearity of concentrations between 0.210 and 0.360 mg/ml, with a correlation coefficient greater than 0.99. The intra-day and inter-day precision calculated as DPR was less than...

Determination of lumiracoxib by a validated stability-indicating MEKC method and identification of its degradation products by LC-ESI-MS studies.

A stability-indicating MEKC method was developed and validated for the analysis of lumiracoxib (LMC) in pharmaceutical formulations using nimesulide as the internal standard (IS). Optimal conditions for the separation of LMC and degradation products were investigated. The method employed 50 mM borate buffer and 50 mM anionic detergent SDS solution at pH 9.0. MEKC method was performed on a fused-silica capillary (50 µm id; effective length, 40 cm) maintained at 30°C. The applied voltage was 20 kV and photodiode array (PDA) detector was set at 208 nm. The method was validated in accordance with the International Conference on Harmonisation requirements. The stability-indicating capability of the method was established by enforced degradation studies combined with peak purity assessment using PDA detection. The degradation products formed under stressed conditions were investigated by LC-ESI-MS and the two degraded products were identified. MEKC method was linear over the concentration range of 5-150 µg/mL (r(2) =0.9999) of LMC. The method was precise, accurate, with LOD and LOQ of 1.34 and 4.48 µg/mL, respectively. The robustness was proved by a fractional factorial design evaluation. The proposed MEKC method was successfully applied for the quantitative analysis of LMC in tablets to support the quality control.