Determinação de fármacos diuréticos em associação por cromatografia em camada delgada e espectrofotometria

A rapid, sensitive and reliable thin-layer chromatography/spectrophotometry screening procedure was developed for quantitative determination of diuretics associated in pharmaceutical dosage forms. The chromatographic method employed microcrystalline cellulose and butanol : acetic acid : water (4:1:1) or amilic alcohol : ammonium hydroxide 25% (9:1) as mobile phases and detection by U.V. light. The drugs were extracted using a simple procedure and were quantified by U.V. spectrophotometry. Results varied from 97.5 to 102.5% and are similar to those obtained by conventional methods. This method of quantification of diuretics is promising for quality control of drugs.

Distinção entre cachaças destiladas em alambiques e em colunas usando quimiometria

One hundred fifteen cachaça samples derived from distillation in copper stills (73) or in stainless steels (42) were analyzed for thirty five itens by chromatography and inductively coupled plasma optical emission spectrometry. The analytical data were treated through Factor Analysis (FA), Partial Least Square Discriminant Analysis (PLS-DA) and Quadratic Discriminant Analysis (QDA). The FA explained 66.0% of the database variance. PLS-DA showed that it is possible to distinguish between the two groups of cachaças with 52.8% of the database variance. QDA was used to build up a classification model using acetaldehyde, ethyl carbamate, isobutyl alcohol, benzaldehyde, acetic acid and formaldehyde as chemical descriptors. The model presented 91.7% of accuracy on predicting the apparatus in which unknown samples were distilled.

Síntese e avaliação da atividade fitotóxica de derivados da α-Santonina

Mixtures of α-Santonin and various solvents were irradiated by either high or low pressure mercury lamps. The photochemical reactions afforded lumisantonin (11) (76% in acetonitrile), (3S,3aS,9bS)-3,6,6-trimethyl-3,3a,4,5-tetrahydronafto[1,2-b]furan-2,7(6H,9bH)dione (12) (100% in acetonitrile), 10α-acetoxy-3-oxo-1,7αH,6,11βH-guaia-4-en-6,12-olide (8) (26% in acetic acid), 10α-hydroxy-3-oxo-1,7αH,6,11βH-guaia-4-en-6,12-olide (10) (32%) and (E)-3-((3S,3aS,7aS)-3-methyl-2-oxo-6-(propan-2-ylidene)hexahydrobenzofuran-7-(7aH)-ylidene)propanoic acid (9) (44%) (in water/ acetic acid 1:1, v/v). Lactone 12 was also prepared by irradiation of lumisantonin in diethyl ether. Lactones 8 and 10 were converted, respectively, into the 10α-acetoxy-3β-hydroxy-1,7αH,6,11βH-guaia-4-en-6,12-olide (13) (87%) and 3β,10α-dihydroxy-1,7αH,6,11βH-guaia-4-en-6,12-olide (14) (75%) by sodium borohydride reduction. The effects of the compounds on the development of radicle of Sorghum bicolor and Cucumis sativus were evaluated.

Teores de compostos orgânicos em cachaças produzidas na região norte fluminense - Rio de Janeiro

This work aimed to quantify some organic compounds in "cachaças" (sugar cane spirit). The ethyl alcohol was quantified by densimetry, after distillation. The acetic acid, methyl alcohol, n-propyl alcohol, n-butyl alcohol, isobutyl alcohol, isoamyl alcohol (mixture of 2-methyl-butyl and 3-methyl-butyl), ethyl acetate and acetaldehyde were determined by gas chromatography; and the furfural, 5-hydroxy-methylfurfural and acrolein by high efficiency liquid chromatography. From the 30 samples analyzed, 63.3% showed non-conformity with national legislation regarding at least one of the analyzed components.

Enriquecimento de compostos fenólicos de folhas de Inga edulis por extração em fase sólida: quantificação de seus compostos majoritários e avaliação da capacidade antioxidante

A phenolic fraction was obtained from of the acetone-water-acetic acid extract of Inga edulis leaves, by liquid-liquid partition and SPE-C18 cartridges. This method provided an increase of 108, 66, 51, 50 and 36% of flavonols, proanthocyanidins, total polyphenols, gallotannins and flavanols, respectively. The major phenolics in purified fraction were procyanidin B2, catechin and myricetin-3-O-α-L-rhamnopyranoside, which achieved increases of 111, 47 and 45%, respectively, after SPE. Acid hydrolysis confirmed the presence of procyanidins, prodelphinidins and glycosylated flavonoids.

Determinação de compostos fenólicos por cromatografia líquida de alta eficiência isocrática durante estacionamento da erva-mate

Different phenolic compound, 5- caffeoylquinic acid (5-CQA), caffeic acid (AC) and rutin (Ru) contents of yerba-mate (Ilex paraguariensis) Brazilian samples of 06 different regions of São Mateus - Paraná, during natural and accelerated industrial storage, were evaluated. For quantification, a reverse phase HPLC isocratic method was developed and validated using methanol:water (35:65 v/v) acidified with 0.5% acetic acid as mobile phase and a photodiode array detector. The six sample global average contents were (34.90 and 36.10 mg g-1) for 5-CQA, (0.18 mg g-1 and 0.23 mg g-1) for AC and (7.12 and 7.18 mg g-1) for Ru, respectively, for the natural and accelerated storage systems. The results showed that the 5-CQA and Ru content are kept constant during the storage while AC content increase only during accelerated storage.

Determinação de ácido acéttico em amostra de vinagre adulterada com ácido clorídrico - um experimento integrado de titulação potenciométrica e condutométrica

The determination of acetic acid in vinegar adulterated sample using simultaneous potentiometric and condutometric titrations was used as an example of integrated experiment in instrumental analysis. An Excel® spreadsheet, which allows the entry of simultaneous data and the construction of the superimposed experimental curves (condutometric, potentiometric, first and second derivative potentiometric curve and, distribution diagrama of the acetic species as function of pH), was used as powerful tool to discuss the fundamental concepts involved in each technique and choose the best of them to quantify, without mutual interference, H3CCOOH and HCl in vinegar adulterated sample.

Síntese e avaliação preliminar da atividade antinociceptiva de novas isoxazolil-aril-hidrazonas

New 2-isoxazoline aldehydes were synthesized, in good yields, from cycloadduct of the 1,3-dipolar cycloaddition reaction between endocyclic enecarbamate and carboethoxyformonitrile oxide (CEFNO). Condensation of these 2-isoxazoline aldehydes with several phenyl-hydrazines produced new isoxazolyl-aryl-hydrazones, which showed low toxicity and excellent antinociceptive activity, when compared to dipyrone. The antinociceptive activity of isoxazolyl-aryl-hydrazones was performed using the acetic acid-induced mice abdominal constrictions test.

Leaf and root volatiles produced by tissue cultures of Alpinia zerumbet (pers.) Burtt & Smith under the influence of different plant growth regulators

Volatiles produced by plantlets of Alpinia zerumbet were obtained by means of simultaneous distillation-extraction (SDE). The effects of indole-3-acetic acid, kinetin, thidiazuron and 6-benzylaminopurine on leaf and root volatile composition obtained by tissue cultures were investigated. A higher content of b-pinene and a lower content of sabinene were observed in leaf volatile of plantlets cultured in control, IAA and IAA+ TDZ media, as compared with those of donor plants. In vitro conditions were favorable to increase caryophyllene content. Volatile compounds from the root were characterized mainly by camphene, fenchyl-acetate and bornyl acetate; which constitute about 60% of total volatile.

Otimização e validação de método multirresíduo para determinação de sulfonamidas em camarão cultivado por cromatografia líquida de alta eficiência com detecção por UV

This work reports the optimization and method validation for sulfonamides (sulfamethazine, sulfaquinoxaline, sulfadimethoxine and sulfathiazole) in shrimp muscle using HPLC-UV. The sulfonamides were extracted with acetonitrile and acetic acid, and the extract cleaned up with a Strata SCX SPE cartridge prior to analysis. The method presented linearity in the range of 20-120 µg kg-1, good linear correlation (r > 0.99), and limits of quantification in the range of 4.7-20.2 µg kg-1. The recovery for shrimp muscles spiked with 50-150 µg kg-1 ranged from 63.2-108.0%. Precision and accuracy analysis showed acceptable relative standard deviation. Commercial shrimps were analyzed and sulfonamides don't were found above of the method limit of quantification.

Isolation and quantitative HPLC-PDA analysis of lupeol in phytopharmaceutical intermediate products from Vernonanthura ferruginea (Less.) H. Rob.

Prior to obtain a standardized dried extract from V. ferruginea, lupeol was first time isolated from leaves and used as chemical maker. An analytical method using HPLC-PDA for lupeol determination in V. ferruginea intermediate products was developed using a C8 reverse-phase column, acetonitrile-acetic acid (99.99:0.01, v/v) as mobile phase at 0.8 mL min-1, oven temperature at 23-25 ºC, sample injection volume at 30 µL and detection at 210 nm. The method presented linearity from 10 to 160 µg mL-1, accuracy, precision, robustness and suitable sensitivity proving to be a useful tool to the obtainment process of lupeol standardized dried extracts of V. ferruginea.

Flavonoids and other bioactive phenolics isolated from Cenostigma macrophyllum (Leguminosae)

This work describes the phytochemical study of stem bark and leaves of Cenostigma macrophyllum Tul. (Leguminosae). Through usual chromatographic techniques were isolated bergenin as the primary compound of the stem bark of and from the leaves gallic acid, methyl gallate, ellagic acid, quercetin, quercetin-3-O-β-D-glucopyranoside, quercetin-3-O-(6"-O-galloyl)-β-D-glucopyranoside (tellimoside), quercetin-3-O-(6"-O-E-p-coumaroyl)-β-D-glucopyranoside (helichrysroside), agathisflavone and vitexin were obtained. The isolates were identified by spectroscopic data analysis, and bergenin showed dose-related antinociception when assessed in acetic acid-induced writhing in mice.

Development and validation of a High Performance Liquid Chromatographic method for determination of etoposide in biodegradable polymeric implants

A method using HPLC-UV was developed and validated for the determination of etoposide incorporated into polycaprolactone implants. The method was carried out in isocratic mode using a C18 column (250 x 4.6 mm; 5 µm), at 25 ºC, with acetonitrile and acetic acid 4% (70:30) as mobile phase, a flow rate of 2 mL/min, and UV detection at 285 nm. The method was linear (r² > 0.99) over the range of 5 to 65 µg/mL, precise (RSD < 5%), accurate (recovery of 98.7%), robust, selective regarding excipient of the sample, and had a quantitation limit equal to 1.76 µg/mL. The validated method can be successfully employed for routine quality control analyses.

Método QuEChERS para determinação de ocratoxina a e citrinina em arroz e farelo de arroz

The present study was carried out to establish the optimal conditions for performing ochratoxin A (OTA) and citrinin (CIT) extraction using the QuEChERS method in rice. Employing the factorial experimental design, variables that significantly influenced the extraction stages were determined. The following variables were analyzed: addition of water, acidification of acetonitrile with glacial acetic acid, as well as amounts of magnesium sulfate, sodium acetate, sodium citrate and diatomaceous earth. The best combining procedure resulted in a predictive model using more water and less diatomaceous earth. Recoveries of CIT and OTA were 78-105%.

Optimization of wood flour acetylation by factorial design and partial least squares regression

Acetylation was performed to reduce the polarity of wood and increase its compatibility with polymer matrices for the production of composites. These reactions were performed first as a function of acetic acid and anhydride concentration in a mixture catalyzed by sulfuric acid. A concentration of 50%/50% (v/v) of acetic acid and anhydride was found to produced the highest conversion rate between the functional groups. After these reactions, the kinetics were investigated by varying times and temperatures using a 3² factorial design, and showed time was the most relevant parameter in determining the conversion of hydroxyl into carbonyl groups.