Voltammetric Determination of Ascorbic Acid in Pharmaceutical Formulations Using Modified Iodine-Coated Platinum Electrode / Determinación voltamétrica del ácido ascórbico en formulaciones farmacéuticas utilizando un electrodo de platino modificado recubierto de yodo

Background: Despite the high reactivity of the platinum electrode, the iodine-coated platinum electrode shows obvious inertness toward adsorption and surface processes. For that, iodine-coated platinum electrodes accommodate themselves to interesting voltammetric applications. Objectives: This study reports using the modified iodine-coated polycrystalline platinum electrode as a voltammetric sensor for ascorbic acid determination in pharmaceutical formulations. Methods: The developed voltammetric method based on recording cyclic voltammograms of ascorbic acid at iodine-coated electrode The optimized experimental parameters for the determination of ascorbic acid were using 0.1 M KCl as a supporting electrolyte with a scan rate of 50mV/s. Results: The anodic peak related to ascorbic acid oxidation was centered at nearly 0.28V. An excellent and extended linear dependence of the oxidative peak current on the concentration of ascorbic acid was observed in the range 2.84x10-3 - 5.68 mM. The limit of detection (LOD) and limit of quantitation (LOQ) were 1.0 µM and 3.01 µM, respectively, attesting to the method's sensitivity. The investigation for the effect of potential interference from multivitamin tablet ingredients (vitamins B1, B6, B12, folic acid, citric acid, sucrose, glucose, and zinc) indicated specific selectivity toward ascorbic acid and the absence of any electrochemical response toward these components. Recovery results in the range 98.93±2.78 - 99.98±5.20 for spiked standard ascorbic acid in pharmaceutical formulations further confirmed the potential applicability of the developed method for the determination of ascorbic acid in real samples. Conclusions: The developed method was successfully applied to the analysis of ascorbic acid (vitamin C), and the obtained results were in good agreement with the labeled values; besides, the statistical tests indicated no significant difference at p=0.05 with a 95% confidence level

Antecedentes: A pesar de su alta reactividad, el electrodo de platino recubierto de yodo muestra una inercia evidente hacia la adsorción y los procesos superficiales. Por ello, los electrodos de platino recubiertos de yodo se adaptan a interesantes aplicaciones voltamétricas. Objetivos: Este estudio informa sobre el uso del electrodo de platino policristalino recubierto de yodo modificado como sensor voltamétrico para la determinación del ácido ascórbico en formulaciones farmacéuticas. Métodos: El método voltamétrico desarrollado se basa en el registro de voltamperogramas cíclicos del ácido ascórbico en el electrodo recubierto de yodo Los parámetros experimentales optimizados para la determinación del ácido ascórbico fueron utilizando KCl 0,1 M como electrolito de soporte con una velocidad de barrido de 50mV/s. Resultados: El pico anódico relacionado con la oxidación del ácido ascórbico se centró en casi 0,28V. Se observó una excelente y extendida dependencia lineal de la corriente del pico oxidativo con respecto a la concentración de ácido ascórbico en el rango 2,84x10-3 - 5,68 mM. El límite de detección (LOD) y el límite de cuantificación (LOQ) fueron 1,0 µM y 3,01 µM, respectivamente, lo que demuestra la sensibilidad del método. La investigación del efecto de la interferencia potencial de los ingredientes de las tabletas multivitamínicas (vitaminas B1, B6, B12, ácido fólico, ácido cítrico, sacarosa, glucosa y zinc) indicó una selectividad específica hacia el ácido ascórbico y la ausencia de cualquier respuesta electroquímica hacia estos componentes. Los resultados de recuperación en el rango de 98,93±2,78 - 99,98±5,20 para el ácido ascórbico estándar adicionado en formulaciones farmacéuticas confirmaron además la potencial aplicabilidad del método desarrollado para la determinación del ácido ascórbico en muestras reales. Conclusiones: El método desarrollado se aplicó con éxito al análisis de ácido ascórbico (vitamina C), y los resultados obtenidos coincidieron con los valores etiquetados; además, las pruebas estadísticas no indicaron diferencias significativas a p=0,05 con un nivel de confianza del 95%

Clarification of ancient works written by foreign researchers on mongolian pharmacology and pharmaceutical formulation / Монголын эм зүй, эм судлал

Abstract@#In recent years, the study of pharmacology and pharmaceutical formulation of traditional Mongolian medicine has been developing significantly. However, there are few research papers on Mongolian pharmacology and development of pharmaceutical formulation written by foreign researchers in ancient times. Therefore, the study was carried out to fill this “gap” and to clarify the ancient works of foreign researchers related to Mongolian pharmacology and development of pharmaceutical formulation.@*Purpose of the study@#To chronologically identify the early works of foreign researchers on the study of pharmacology and pharmaceutical formulation of traditional Mongolian medicine.@*Research method@#Hermeneutic approach, analysis of ancient textbook, and analysis and synthesis methods were used.@*Conclusion@#According to facts and eyewitnesses in the book of Zhouhou Beijifang (Emer- gency Prescriptions) by Ge Hong (261-341) of the Jin Dynasty, Jingui Yaolüe (Essential Prescriptions from the Golden Cabinet) by Chang Ji, the Northern Han Dynasty’s notes on “Xiongnu Doctors Carry Toxic Drugs”, Jāmiʿ al-Tawārīkh (Compendium of Chronicles) by Rashid-ad-Din, William de Rubruck’s “Journey to the Orient”, and book of Plano Carpini, an Italian tourist, the development of pharmacology and pharmaceuticals in traditional Mongolian medicine dates back to the Xiongnu period. Later, in the fourteenth century, it became an independent system of medical knowledge of many nations, as evidenced by the writings of Chinese, Persian, French, and Italian scholars as well as religious envoys.

Evaluation of physicochemical properties as supporting information on quality control of raw materials and veterinary pharmaceutical formulations / 药物分析学报

This study aimed to show that the physicochemical proprieties obtained by Fourier transform infrared spectroscopy (FTIR), thermogravimetry (TG), and scanning electronic microscopy (SEM) can be useful tools for evaluating the quality of active pharmaceutical ingredients (APIs) and pharmaceutical products. In addition, a simple, sensitive, and efficient method employing HPLC-DAD was developed for simulta-neous determination of lidocaine (LID), ciprofloxacin (CFX) and enrofloxacin (EFX) in raw materials and in veterinary pharmaceutical formulations. Compounds were separated using a Gemini C18 (250 mm × 4.6 mm, 5 μm) Phenomenex ? column, at a temperature of 25 °C, with a mobile phase containing 10 mM of phosphoric acid (pH 3.29): acetonitrile (85.7:14.3, v/v) and a flow rate of 1.5 mL/min. Physicochemical characterization by TG, FTIR, and SEM of raw materials of LID, CFX, and EFX provided information useful for the evaluation, differentiation, and qualification of raw materials. Finally, the HPLC method was proved to be useful for evaluation of raw material and finished products, besides satisfying the need for an analytical method that allows simultaneous determination of EFX, CFX, and LID, which can also be extended to other matrices and applications.

Estudo da separação de glicocorticoides e aplicações em formulações farmacêuticas utilizando eletroforese capilar / Study of the separation of glucocorticoids and application in pharmaceutical formulations using capillary electrophoresis

Estudos envolvendo os glicocorticoides merecem destaque devido a serem hormônios responsáveis pela transferência de informações e instruções às células, desta forma regulando o metabolismo, desenvolvimento, crescimento, função imune e também auxiliam no controle das funções tanto reprodutivas quanto tecidual. Estes também são sintetizados e amplamente utilizados com finalidade terapêutica processos alérgicos, tratamento de doenças autoimunes, em transplantes no pré-operatório e/ou pós-operatório-, devido a sua eficiente ação como imunossupressores e anti-inflamatórios. Os dois primeiros capítulos deste trabalho exibem uma revisão da literatura com foco em considerações gerais sobre os glicocorticoides, metodologias empregadas na análise destes hormônios e fundamentos da eletroforese capilar. Na sequência, o quarto capitulo, mostra a otimização da separação de 17 glicocorticoides utilizando cromatografia eletrocinética micelar devido a alto grau hidrofóbico dos analitos. Para tal, a composição do eletrólito consistiu em 20mM de tetraborato de sódio (pH=9.3) e 30 mM de dodecil sulfato de sódio (como surfactante), e a interação soluto-micela e, portanto, retenção do soluto, foi manipulada com a adição (volume/volume) de solventes orgânicos na composição de até 20% acetonitrila (ACN), 20% etanol (EtOH) e 1% tetrahidrofurano (THF), a qual se baseia num modelo de desenho de misturas (totalizando dez diferentes eletrólitos), e através desta abordagem um ótimo de separação foi obtido (13,3% EtOH, 3,3% ACN e 0,17% THF). A melhor condição de separação foi testada qualitativamente numa amostra de urina de um voluntário que faz uso contínuo de prednisona como terapia corticoidal. As misturas de solventes estudadas neste trabalho afetam a solubilidade dos hormônios na fase aquosa e a estrutura micelar também sofre grande impacto,principalmente na camada de solvatação. O quarto capítulo busca racionalizar tais efeitos através da obtenção de descritores, e as informações contidas nos descritores hidrofóbicos e hidrofílicos são sempre relevantes e contribuem nas correlações encontradas. Obteve três grupos de comportamento distinto, onde a capacidade doadora e aceptora de prótons para a realização de ligações de hidrogênios foram as interações consideradas as mais relevantes para o comportamento observado da separação. E o capítulo final, apresenta possibilidades de aproveitamento no controle de qualidade na indústria farmacêutica, métodos baseados na injeção e tensão inversas foram propostos a fim de ganho de tempo de análise (máximo de 5 minutos), estes foram validados seguindo o protocolo preconizado pela ANVISA (Agência Nacional de Vigilância Sanitária) nos parâmetros: precisão, exatidão, seletividade, linearidade, limites de detecção e quantificação e robustez; e aplicados na quantificação de quatro (diferentes formulações comerciais contendo glicocorticoides (prednisona 20 mg, betametasona 4 mg, furoato de mometasona 200 mcg e dipropionato de beclometasona 200 mcg)

Studies involving glucocorticoids deserve to be highlighted because they are hormones responsible for the transfer of information and instructions to cells, thus regulating metabolism, development, growth, immune function and also assist in the control of both reproductive and tissue functions. These are also synthesized and widely used for therapeutic purposes - allergic processes, treatment of autoimmune diseases, in preoperative and/or postoperative transplants - due to their efficient action as immunosuppressants and anti-inflammatories. The first two chapters of this paper present a review of the literature focusing on general considerations about glucocorticoids, methodologies used in the analysis of these hormones and fundamentals of capillary electrophoresis. Subsequently, the fourth chapter shows the optimization of the separation of 17 glucocorticoids using micellar electrokinetic chromatography due to the high hydrophobic degree of the analytes. To this end, the electrolyte composition consisted of 20 mM sodium tetraborate (pH = 9.3) and 30 mM sodium dodecyl sulfate (as a surfactant), and the solute-micelle interaction and therefore solute retention was manipulated with organic solvent in the composition of up to 20% acetonitrile (ACN), 20% ethanol (EtOH) and 1% tetrahydrofuran (THF), which is based on a mixture design model (totaling ten different electrolytes), and through this approach an optimal separation was obtained (13.3% EtOH, 3.3% ACN and 0.17% THF). The best separation condition was qualitatively tested in a urine sample from a volunteer who makes continuous use of prednisone as corticosteroid therapy. The solvent mixtures studied in this work affect the solubility of the hormones in the aqueous phase and the micellar structure also has a great impact, especially on the solvation layer. The fourth chapter seeks to rationalize these effects by obtainingdescriptors, and the information contained in the hydrophobic and hydrophilic descriptors is always relevant and contributes to the correlations found. It obtained three groups of distinct behavior, where the donor and acceptor capacity of protons for the realization of hydrogen bonds were the interactions considered the most relevant for the observed behavior of the separation. And the final chapter presents possibilities of use in quality control in the pharmaceutical industry, methods based on injection and reverse voltage were proposed in order to gain analysis time (maximum of 5 minutes), these were validated following the protocol recommended by ANVISA (Brazilian National Agency of Sanitary Surveillance) in the parameters: precision, accuracy, selectivity, linearity, limits of detection and quantification and robustness; and applied in the quantification of four different commercial formulations containing glucocorticoids (prednisone 20 mg, betamethasone 4 mg, mometasone furoate 200 mcg and beclomethasone dipropionate 200 mcg)

Pharmaceutical development of tablets containing a spray-dried optimized extract from Lippia origanoides H. B. K.: influence of excipients and toxicological assessment

ABSTRACT Lippia origanoides is a honey shrub which has showed hypotensive potential assessed by in vivo studies. The aim of this work is the development of a pharmaceutical formulation composed by an optimized extract obtained from aerial parts of L. origanoides. The quantification of the naringenin marker in the dry extract and tablets developed was performed, as well as the assessment of the oral acute toxicity in rats. The hydroalcoholic extract of L. origanoides was spray-dried with the addition of colloidal silicon dioxide (Lo-HAE/CSD), and then applied in the preparation of eight different lots of tablets. The influence of the diluent (cellulose or babassu mesocarp), the presence of binder, and the percentage of lubricant, as well as organoleptic and physicochemical characteristics were screened. For the quantification of the marker content both in Lo-HAE/CSD and in the tablets, an analytical curve of the naringenin standard was fitted, and the samples were then analyzed in UFLC. The toxicological assessment was performed in female Wistar rats according to the Acute Toxic Class Method from OECD. The developed tablets produced meet acceptable macroscopic characteristics, and the presence of babassu as diluent provided improved physicochemical properties. The best content of Lo-HAE/CSD in the tablet (100.27%) was identified for the lot containing babassu, composed by 1.0% magnesium stearate, without PVP binder in its formulation. Moreover, Lo-HAE/CSD showed no signs of toxicity. Therefore, the babassu mesocarp powder is a promising pharmaceutical excipient for the development of herbal tablets containing the Lippia origanoides extract.

Simultaneous estimation of Esomeprazole and Tadalafil in pharmaceutical formulations using High Performance Liquid Chromatography.

An easily, specific, precise, and accurate reversed-phase HPLC method was developed and validated for simultaneous estimation of esomeprazole ( Nexium®) and tadalafil (Cialis®) in pharmaceutical formulation. The separation was achieved by using Hypersil BDS C18 column (250 mm × 4.6 mm; 5.0 μm) and acetonitrile: 0.05 M potassium dihydrogen phosphate buffer at pH 6 adjusted with phosphoric acid as a mobile phase at a flow rate of 1 mL/min. Detection was carried out at wavelength 285nm. The retention time of esomeprazole and tadalafil were 3.1, 3.7 min, respectively. The linearity was established over the concentration ranges of 60-180μg/mL and 40-120μg/mL with correlation coefficients 0.9998 and 0.9996 for esomeprazole and tadalafil, respectively. The mean recoveries were found to be in the ranges of 98–102% for esomeprazole and tadalafil. The proposed method has been validated as per ICH guidelines and successfully applied to the simultaneous estimation of esomeprazole and tadalafil in pharmaceutical formulation.

Voltammetric quantitation of nitazoxanide by glassy carbon electrode / 药物分析学报

The present study reports voltammetric reduction of nitazoxanide in Britton-Robinson (B-R) buffer by cyclic and square-wave voltammetry at glassy carbon electrode. A versatile fully validated voltammetric method for quantitative determination of nitazoxanide in pharmaceutical formulation has been proposed. A squrewave peak current was linear over the nitazoxanide concentration in the range of 20-140 mg/mL. The limit of detection (LOD) and limit of quantification (LOQ) was calculated to be 5.23μg/mL and 17.45μg/mL, respectively.

Voltammetric quantification of anti-hepatitis drug Adefovir in biological matrix and pharmaceutical formulation / 药物分析学报

Electrochemical reduction behavior of Adefovir was studied using Hanging Mercury Drop Electrode (HMDE) in Britton-Robinson (BR) buffer solution.Voltammetric study showed one well-defined reduction peak in the potential range -1.2 to -1.4 V (vs.Ag/AgCl) due to reduction of C=N bond of the imidazole ring.Solid-phase extraction and protein-precipitation techniques were employed for extraction of Adefovir from human plasma.The proposed method allows quantification of Adefovir in human plasma over the concentration range 0.50-5.00 μg/mL with the detection limit 0.17 μg/mL,whereas in pharmaceutical formulation 0.25-2.25 μg/mL with the detection limit 0.08 μg/mL.

RP-HPLC method for the estimation of nitroxazepine hydrochloride in pharmaceutical dosage forms.

A simple and sensitive isocratic RP‐HPLC method was developed for the determination of Nitroxazepine hydrochloride in bulk drug and its pharmaceutical tablet formulations where the mobile phase optimized was Phosphate buffer : Acetonitrile (70:30) and Phenomenex C18 column (250 mm length, 4.6 mm internal diameter and particle size 5 μm) was used as the stationary phase. The flow rate and detection wavelength was 1.0 mL min‐1 and 265 nm respectively. The developed method was validated as per ICH guidelines for specificity, linearity and range, precision, accuracy, robustness, limit of quantification and limit of detection. The results of all the validation parameters were well within their acceptance values. The method gave good recovery in the range of 98.95‐99.43 % for Nitroxazepine hydrochloride when it was applied for its determination in pharmaceutical tablet formulations.