RESUMO
SUMMARY The purpose of this study was to evaluate physicochemical properties and dissolution studies of furosemide (FUR), hydrochlorothiazide (HCTZ) and nifedipine (NIF), low water solubility drugs, in raw materials and pharmaceutical formulations. Surface and physicochemical characterization techniques -scanning electronic microscopy (SEM), thermogravimetry (TG), X-ray diffraction (XRD) and infrared (IR) spectrometry- as well as physical and physicochemical tests on tablets and capsules were applied as supporting information on drug quality control. Simple, rapid, and efficient UV-Vis methods were developed and validated for the determination of FUR, HCTZ and NIF samples. SEM exhibited considerable differences in the crystal morphological structures. Among the drugs studied, except for furosemide, more than one polymorph was present in the samples. Drug release profiles were satisfactory for all products. FUR and HCTZ tablets exhibited similar dissolution profiles, with very rapid release to the pharmaceutical specialties (reference, similar and generic). For HCTZ tablets, the similar drug (f2= 48.74) is not equivalent to the reference drug. NIF capsules (reference and compounded) showed a release >80% of stated on product labels, in 10 minutes. The results obtained in this study suggest that the quality parameters and drug dissolution profiles may have been influenced by the morphology and size of the crystals, excipients, and technological processes.
RESUMEN El propósito de este estudio fue evaluar las propiedades fisicoquímicas y los estudios de disolución de furosemida (FUR), hidroclorotiazida (HCTZ) y nifedipina (NIF), medicamentos de baja solubilidad en agua, en materias primas y formulaciones farmacéuticas. Técnicas de caracterización fisicoquímica y de superficie: microscopía electrónica de barrido (SEM), termogravimetría (TG), difracción de rayos X (XRD) y espectrometría infrarroja (IR), así como pruebas físicas y fisicoquímicas en tabletas y cápsulas que se aplicaron como información de apoyo sobre el control de calidad. Se desarrollaron y validaron métodos simples, rápidos y eficientes de UV-Vis para la determinación de muestras de FUR, HCTZ y NIF. SEM exhibió diferencias considerables en las estructuras morfológicas de cristal. Entre las drogas estudiadas, a excepción de la furosemida, más de un polimorfo estaba presente en las muestras. Los perfiles de liberación de fármacos fueron satisfactorios para todos los productos. Las tabletas FUR y HCTZ exhibieron perfiles de disolución similares, con una liberación muy rápida a las especialidades farmacéuticas (referencia, similares y genéricas). Para las tabletas de HCTZ, el medicamento similar (f2= 48,74) no es equivalente al medicamento de referencia. Las cápsulas NIF (de referencia y compuestas) mostraron una liberación >80% de la indicada en las etiquetas del producto, en 10 minutos. Los resultados obtenidos en este estudio sugieren que los parámetros de calidad y los perfiles de disolución del fármaco pueden haber sido influenciados por la morfología y el tamaño de los cristales, excipientes y procesos tecnológicos.
RESUMO
The use of vermicompost (humified material) for treating wastewaters, remediating polluted soils, improving agricultural productivity, protecting crop production, and developing sensitive analytical methods is reviewed here, covering the past 17 years. The main advantages of vermicompost, considering all applications covered in this paper, comprise (i) easy acquisition, (ii) low costs, (iii) structural, chemical, and biological characteristics responsible for exceptional adsorptive capacities as well as pollutant degradation, and (iv) the promotion of biocontrol. Specifically, for wastewater decontamination, a considerable number of works have verified the adsorption of toxic metals, but the application of vermicompost is still scarce for the retention of organic compounds. Problems related to the final disposal of enriched vermicompost (after treatment steps) are often found, in spite of some successful destinations such as organic fertilizer. For decontaminating soils, the use of vermicompost is quite scarce, mainly for inorganic pollutants. In agricultural productivity and biocontrol, vermicompost imparts remarkable benefits regarding soil aggregation, plant nutrition, and the development of beneficial microorganisms against phytopathogens. Finally, the use of vermicompost in sensitive analytical methods for quantifying toxic metals is the newest application of this adsorbent.
