Análises quali- e quantitativa de cafés comerciais via ressonância magnética nuclear

Coffee is one of the beverages most widely consumed in the world and the "cafezinho" is normally prepared from a blend of roasted powder of two species, Coffea arabica and Coffea canephora. Each one exhibits differences in their taste and in the chemical composition, especially in the caffeine percentage. There are several procedures proposed in the literature for caffeine determination in different samples like soft drinks, coffee, medicines, etc but most of them need a sample workup which involves at least one step of purification. This work describes the quantitative analysis of caffeine using ¹H NMR and the identification of the major components in commercial coffee samples using 1D and 2D NMR techniques without any sample pre-treatment.

Sistema de almacén y dispensación robotizada de productos farmacéuticos

Actualmente, las necesidades de mejora en gestión de stocks y la mayor disponibilidad de sistemas automáticos, están haciendo que muchas empresas inviertan en técnicas modernas para almacenamiento y manipulación de productos. Esta inquietud también ha llegado a las farmacias, que de forma lenta pero firme se van apuntando a su robotización. Uno de los principales problemas a los que se enfrentan las farmacias es la pérdida de tiempo en la gestión y búsqueda de medicamentos, provocando situaciones negativas como las esperas, la falta de tiempo para una atención más personalizada y como consecuencia, la pérdida de clientes. Este inconveniente y la necesidad de mejora en la gestión de los stocks han hecho que aparezcan los Sistemas de dispensación automática de productos farmacéuticos. El dispensador automático facilita el trabajo del farmacéutico al automatizar la búsqueda de la medicina requerida, aumentando la dedicación al cliente y reduciendo los tiempos no productivos y las colas. El presente estudio desarrolla un sistema de dispensación automático de fármacos aplicado a farmacias con una rotación de medicamentos media/ baja, valorando tanto su viabilidad técnica como económica. El almacén propuesto es de tipo caótico con sistema de carga, almacenamiento y descarga completamente automáticos. La mayoría de diseños y conceptos expuestos en este trabajo son de desarrollo propio del autor con el único objetivo de la búsqueda de nuevas soluciones para conseguir un sistema de almacenamiento efectivo y de máximo rendimiento.

Determinação espectrofotométrica de citrato de sildenafil em formulações farmacêuticas

This paper describes a simple and rapid spectrophotometric method for quantitative determination of sildenafil citrate based on its reaction with p-chloranil accelerated by hydrogen peroxide, producing a stable purple compound (λmax= 535 nm). In the absence of peroxide this reaction is very slow. The experimental conditions were optimized by using response surface methodologies. Beer's law is obeyed in a concentration range of 8.52 x 10-5 - 1.70 x 10-3 mol L-1 (r = 0.999). The detection limit was 1.96 x 10-5 mol L-1. The method was successfully applied for the determination of sildenafil citrate in medicines with good accuracy and precision.

Uso de scanner em espectrofotometria de absorção molecular: aplicação em experimento didático enfocando a determinação de ácido ascórbico

Quantitative analysis of colored substances is generally performed using a spectrophotometer for detection of radiation. However, the combination of digital images and mathematical conversion of colors is an alternative for quantitative procedures based on colored chemical reactions. This work proposes a didactic experiment using a scanner for determination of ascorbic acid in medicines based on the formation of the Prussian blue complex. Results were in good agreement with a conventional spectrophotometer method and the procedure is attractive for instrumental analysis undergraduate courses.

Ácidos ciclopentênicos do óleo da sapucainha (Carpotroche brasiliensis Endl, Flacourtiaceae): o primeiro antileprótico usado no Brasil

The chaoolmugra oil is one of the oldest medicines used for leprosy until the development of sulfas. In Brazil, it is known as sapucainha oil that is obtained from Carpotroche brasilienesis seeds (Flacourtiaceae). Chemical and medicinal studies of sapucainha oil were introduced in Brazil by Peckolt, Cole and Cardoso which showed that major ciclopentenyl fatty acids as chaulmoogric, hydnocarpic and gorlic were responsible for its bactericidal activity. In this work, a method for quantification of sapucainha oil acidic fraction by HRGC was established using methyl n-heptadecanoate as internal standard. The oil chemical stability was investigated by the use of GC-MS, IR, ¹H and 13C NMR and showed that the main degradation products belong to the cyclopentenyl moiety oxidation.

Biodiversidade: fonte potencial para a descoberta de fármacos

In economic terms, biodiversity transcends the boundaries usually given to conventional industries because it is a valuable source of biological and chemical data of great use to drug discovery. Certainly, the use of natural products has been the single most successful strategy in the discovery of novel medicines, and most of the medical breakthroughs are based on natural products. Half of the top 20 best-selling drugs are natural products, and their total sales amounted to US$ 16 billions shows the importance of natural products, which is evidenced by the new chemical entities (NCE) approved by regulatory authorities around the world in the past decade. Recently, the approval of the alkaloid galanthamine as a medicine to treat Alzheimer's disease shows that natural compounds from plants will continue to reach the market. The huge biological diversity of the Brazilian biomes, by its ability to generate new knowledge and technological innovation can be a fantastic alternative as raw material for drug discovery.

Química e farmacologia de quimioterápicos antineoplásicos derivados de plantas

This review demonstrates the importance of plants as sources of molecules used in anticancer therapies. The approach is performed by relating the active molecules to their origins, details, mechanisms of action, structure-activity relationship and chemical characteristics of chemotherapeutical medicines. It was also described the development of anticancer agents from plants by the pharmaceutical industry and the difficulties to release these compounds as a trademark. These include the well known paclitaxel, docetaxel, vincristine, vinblastine, vinorelbine, vindesine, etoposide, teniposide, and other molecules that are undergoing clinical trials.

Construção de espectrômetro de emissão atômica com atomização eletrotérmica em filamento de tungstênio (WCAES)

It is here discussed the development of a low cost analytical instrument with capacity for metals determination using atomic emission measurements in an electrothermal atomization system with a tungsten coil atomizer. The main goal was to show a new frontier for using this atomizer and to demonstrate that the simple instrumental arrangement here proposed has potential for portability and for solving analytical tasks related to metals determination. Atomic emission of calcium was selected for the adjustment of instrumental parameters and to evaluate the main characteristics of the lab-built instrument. Cobalt was determined in medicines and one alloy to demonstrate its feasibility.

A quantitative validated method using liquid chromatography and chemometric analysis for evaluation of raw material oF Maytenus ilicifolia (Schrad.) Planch., Celastraceae

The hydroalcoholic extracts prepared from standard leaves of Maytenus ilicifolia and commercial samples of espinheira-santa were evaluated qualitatively (fingerprinting) and quantitatively. In this paper, fingerprinting chromatogram coupled with Principal Component Analysis (PCA) is described for the metabolomic analysis of standard and commercial espinheira-santa samples. The epicatechin standard was used as an external standard for the development and validation of a quantitative method for the analysis in herbal medicines using a photo diode array detector. This method has been applied for quantification of epicatechin in commercialized herbal medicines sold as espinheira-santa in Brazil and in the standard sample of M. ilicifolia.

Avaliação de métodos de extração para a determinação de cromo e níquel em formulações farmacêuticas e em matérias-primas usadas na fabricação de medicamentos à base de cefalexina e ciprofloxacino

This paper reports the evaluation of extraction strategies for the treatment of medicine samples to determine chromium and nickel by GFAAS. Different approaches for extraction were evaluated and the most efficient involved magnetic stirring. The metals were quantitatively extracted by stirring 0.20 g samples with 25 mL of 2.0 mol L-1 HCl solution for 60 min. The developed method was successfully applied for the determination of Cr and Ni in tablets containing antibiotics and raw materials, with cephalexin and ciprofloxacin as active ingredients.

Tropical biodiversity: has it been a potential source of secondary metabolites useful for medicinal chemistry?

The use of natural products has definitely been the most successful strategy in the discovery of novel medicines. Secondary metabolites from terrestrial and marine organisms have found considerable use in the treatment of numerous diseases and have been considered lead molecules both in their natural form and as templates for medicinal chemistry. This paper seeks to show the great value of secondary metabolites and emphasize the rich chemical diversity of Brazilian biodiversity. This natural chemical library remains understudied, but can be a useful source of new secondary metabolites with potential application as templates for drug discovery.

Desafios da indústria farmacêutica brasileira

The paper traces a panorama of the development of new drugs and hopes to contribute for Brazil to become a player in the discovery of new drugs. Brazil is the sixth world market retail consumer of medicines prone to expansion, has a pharmaceutical industry focused on the production of generics and a very large number of undergraduate courses in Pharmacy. The national industry has grown over the last decade after the Generics Act 9787/99. Despite these positive aspects, a number of bottlenecks prevent Brazilian pharmaceutical industry to invest in the development of new drugs. There are, however, a number of initiatives to reduce the dependence on imported generic drugs. It is a very good start for the development of new pharmaceutical drugs.

Eletrodo compósito à base de grafite-Araldite®: aplicações didáticas - parte II

This work proposes the use of a graphite-Araldite® 70% (graphite, m/m) composite electrode in didactic experiments, specifically in the quantitative determination of the neurotransmitter dopamine (DA) in a sample of pharmaceutical formulation. The goal is to demonstrate the possibility of using voltammetric techniques in quality control of medicines, besides covering some concepts such as the influence of pH on the redox process, the differential pulse voltammetry (DPV) technique, the optimization of experiments and comparison with an official method described in the United States Pharmacopoeia.

Determination of hydrochlorothiazide in pharmaceutical formulations by diffuse reflectance spectroscopy

This paper describes a method for quantitative spot test analysis of hydrochlorothiazide using diffuse reflectance spectroscopy. The reflectance measurements were performed analyzing the colored compound (l = 585 nm) produced from the reaction between hydrochlorothiazide and p-dimethylaminocinnamaldehyde (PDAC) in acid medium. This reaction occurred on filter paper after heating to 80ºC for 8 minutes. Factorial designs allowed varying multiple reaction factors simultaneously in order to obtain the best reaction conditions. These factors included heating temperature, heating time, acid volume and PDAC volume. The linearity was studied in the range of 3.36x10-2 to 1.01x10-1 mol L-1 with a correlation coefficient of 0.998. The limit of detection was estimated to be 1.32x10² mol L-1. Commercial samples were analyzed using the proposed method and the results were favorably compared with those of the United States Pharmacopeia method, showing that quantitative spot test analysis by diffuse reflectance could be successfully used to determine hydrochlorothiazide in medicines.

Supersaturation-controlled crystallization

Identification of product requirements and quality, together with the management of production are key issues in chemical engineering. Quality control of crystalline products is part of the quality of many industrially manufactured products like paper, paintings, medicines and fertilizers. In most crystallization cases, quality is described with the size, polymorph, shape and purity of the crystal. The chemical composition, hydrodynamics and driving force, together with the operating temperature are in a key position when the properties of a crystalline product are controlled with the crystallization process. This study concentrates on managing the identified properties of a crystalline product with the control of a driving force. The controlling of the driving force can be based on the change of solubility or the change of concentration. Solubility can be changed with temperature, pressure and an antisolvent. The concentration of crystallizing compound, the solute can be changed with the evaporation of the solvent and with the addition of a reagent. The present study focuses on reagent addition and temperature change as methods of changing the level of the driving force. Three control structures for direct control of supersaturation are built, one for cooling crystallization and two for reactive crystallization. Closed loop feedback control structures are based on the measurement of the solute concentration with attenuated total reflection - Fourier transform infrared spectrometer. The details of the reagent feed are analyzed with experimental studies and with results of computational fluid dynamic simulations of the inert particle pulse in the premixer and inert particle injection to the mixing tank. Nucleation in conditions of controlled reactive crystallization is analyzed with Nielsen’s equation of homogeneous nucleation. The resulting control systems, based on regulation of supersaturation, can be used to produce the desired polymorph of an organic product. The polymorph composition of product crystals is controlled repeatably with the decision of a set value of supersaturation level.