Evaluation of hard gelatin capsules and hydroxypropyl methylcellulose containing ampicillin

This study aims to develop and evaluate formulations containing ampicillin in capsules of gelatin and hydroxypropyl methylcellulose (HPMC). Two formulations (A and B) were developed. The final product quality was evaluated by testing for quality control and the results were in agreement with the Brazilian Pharmacopoeia. The formulations with HPMC capsules showed lower percentages of drug dissolved (99.67%, HPMC-A and 87.70%, HPMC-B) than the gelatin (100.18%, GEL-A and 101.16% GEL-B). Because of the delay of the ampicillin release observed in the dissolution profiles, it becomes necessary to evaluate the drugs that can be conditioned in the HPMC capsules.

A fluorescence-based assay for octreotide in kinetic release from depot formulations

Here we report the validation of a derivatization method that makes use of fluorescamine as a selective reactant for the quantitative analysis of peptide and protein drugs in the dissolution profile from depot formulations. Typical current methods require separation of the nano/microparticles and time-consuming chromatographic runs. In this study we report a method which can be conducted without the need for complete physical separation of the particles or removal of the unreacted probe. This method was used here for the analysis of the release profile of octreotide in a depot formulation, with results in excellent agreement with reported chromatographic assays.

Solution thermodynamics of methocarbamol in some ethanol + water mixtures

Apparent thermodynamic functions, Gibbs energy, enthalpy and entropy of solution and mixing, for methocarbamol in ethanol + water mixtures, were evaluated from solubility data determined at temperatures from 293.15 K to 313.15 K and from calorimetric values of drug fusion. The drug solubility was greatest in the mixtures with 0.70 or 0.80 mass fraction of ethanol and lowest in neat water across all temperatures studied. Non-linear enthalpy-entropy compensation was found for the dissolution processes. Accordingly, solution enthalpy drives the respective processes in almost all the solvent systems analyzed.

Desenvolvimento e validação de um método analítico por espectrofotometria UV para quantificação de carvedilol

This paper reports the development and validation of a new analytical method using UV spectrophotometry to quantify carvedilol (CRV) in hydrophilic matrices and raw material. This method was shown to be linear, accurate, precise, robust and to have adequate limits of quantification and detection (LQ and LD, respectively), allowing its use in the dissolution test of hydrophilic matrices. The content of CRV determined through this method was compared with two previously validated methods based on the reference techniques of High Performance Liquid Chromatography (HPLC) and Potentiometric Titrations (PT). ANOVA confirmed the equivalence of these methods, showing no significant differences.

Interaction of naproxen with calcium carbonate: physicochemical characterization and in vitro drug release studies

Interaction and physicochemical characterization of dispersions of naproxen in calcium carbonate after freeze-drying the wet-state equilibrated mixture have been investigated by analytical methods. The FT-IR study revealed the acid-base reaction between naproxen and calcium carbonate. The DSC study indicated physical interaction and significantly diminished crystallinity of naproxen in the formulation containing higher quantities of calcium carbonate. Furthermore, the SEM study showed the reduced particle size and loss of crystalline morphology in the same sample. Drug release increased with the increase of calcium carbonate in the formulations. Formulation of naproxen with calcium carbonate in 1:2 ratio allowed its dissolution to the greatest extent (94.96%) while other compositions, 1:0.5 and 1:1, showed 80.86% and 78.30% release, respectively.

Influência de parâmetros de processo na obtenção de sílica a partir de cinza da casca de arroz pela ação de Fusarium oxysporum

In this work, an experimental design was used to analyze the influence of process parameters on the production of extracellular enzymes such as β-glucosidase and peroxidase, and their possible effect on the obtention of soluble and nanostructured silica from rice husk ash by the action of the fungus Fusarium oxysporum. Specifically, pH, fermentation time and glucose concentration in the culture medium were varied. Statistical analysis indicated that the silica synthesis in the aqueous medium was strongly dependent on pH and time. Although the glucose concentration does not exert a direct influence on the biosynthesis of silica, it is an important parameter in the production of extracellular enzymes. To prevent enzyme inhibition and provide higher dissolution of silica, it is recommended to work at a pH close to neutral with a glucose concentration of 3 g L-1 for at least 144 h.

Inertization of small-scale chemical wastes using iron phosphate glass

The viability of small-scale heavy-metal waste immobilization into iron phosphate glasses was investigated. Several waste forms containing different amounts of heavy-ion wastes were evaluated (5%, 10%, 15%, 20%, 26%, 33%, 40% and 50% by mass) and their X-ray diffraction patterns revealed that no crystallization occurred in glasses with waste concentrations up to 26%. The dissolution rates for all of the reported glass compositions (ca. 10-8 g cm-2 min-1) are similar to those reported for the materials most commonly used for waste vitrification. Iron phosphate glasses thus proved to be very useful for the immobilization of heavy-metal wastes, exhibiting good contention and chemical durability comparable to that of borosilicate glasses.

Remoção do ácido mefenâmico em água utilizando carvão ativado em pó, lama vermelha e oxidação com cloro

The use of activated carbon powder (ACP), red mud and oxidation with chlorine to remove mefenamic acid in water are described, aimed at their application as a complement to sewage treatment processes in Brazil. A study on the behavior of mefenamic acid in water was performed by evaluating its dissolution for different concentrations and times. Subsequently, the optimal conditions for removal of mefenamic acid were investigated using ACP adsorption at different pH and concentrations, and red mud adsorption using different pH. The utilization of different pH and times was also investigated to establish the ideal conditions for chemical oxidation of the drug. Among the different conditions studied, the best condition for drug removal by ACP and red mud were 100% and 96%, respectively, while the best condition for chemical oxidation occurred using solutions with pH 6 and 7 and reaction times of 30 and 60 minutes.

Coprecipitation of trace amounts of silicon with aluminum hydroxide and the determination by flame atomic absorption spectrometry

A simple preconcentration method of silicon based on coprecipitation with aluminum hydroxide prior to its flame atomic absorption (FAAS) determination was established. The recovery values of analyte ion was higher than 95%. The parameters including types of hydroxide ion source for precipitation, acid type for dissolution step, amount of aluminum ion as collector, pH, temperature, standing and centrifuge time, and sample volume were optimized for the quantitative recovery of the analyte. The influences of matrix ions were also examined. The relative standard deviation was found to be 3.2%. The limit of detection was calculated as (0.1 mg L-1). The preconcentration factor is 100 for (200 mL) solution. The proposed method was successfully applied for the determination of silicon in some water and alloy samples.

DETERMINAÇÃO ESPECTROFOTOMÉTRICA DE METILDOPA EM ENSAIO DE DISSOLUÇÃO DE COMPRIMIDOS UTILIZANDO EXTRATO DE RABANETE COMO FONTE DE PEROXIDASE

An enzymatic spectrophotometric method for the determination of methyldopa in a dissolution test of tablets was developed using peroxidase from radish (Raphanus sativus). The enzyme was extracted from radish roots using a phosphate buffer of pH 6.5 and partially purified through centrifugation. The supernatant was used as a source of peroxidase. The methyldopachrome resulting from the oxidation of methyldopa catalyzed by peroxidase was monitored at 480 nm. The enzymatic activity was stable for a period of at least 25 days when the extract was stored at 4 or -20 ºC. The method was validated according to RDC 899 and ICH guidelines. The calibration graph was linear in the range 200-800 µg mL-1, with a correlation coefficient of 0.9992. The limits of detection and quantification in the dissolution medium were 36 and 120 µg mL-1, respectively. Recovery was greater than 98.9%. This method can be applied for the determination of methyldopa in dissolution tests of tablets without interference from the excipients.

MICROEMULSÕES: COMPONENTES, CARACTERÍSTICAS, POTENCIALIDADES EM QUÍMICA DE ALIMENTOS E OUTRAS APLICAÇÕES

Microemulsions (MEs) are thermodynamically stable systems consisting of nanosized droplets dispersed in a solvent continuous medium (known as pseudo-phase), which is immiscible with the dispersed phase. These systems consist of water, a hydrophobic solvent called "oil," an amphiphile and often, a co-surfactant that is normally a medium chain alcohol. A large number of publications describe the importance of MEs in many branches of chemistry, and there is an intensive search for new applications. In addition, MEs have been applied in many areas, including oil extraction, removal of environmental pollutants from soils and effluents, dissolution of additives in lubricants and cutting oils, cleaning processes, dyeing and textile finishing, as nanoreactors to obtain nanoparticles of metals, semiconductors, superconductors, magnetic and photographic materials, and latex. However, only some studies indicate the potential applications of MEs in food and even fewer evaluate their chemical behavior. Potential applications of MEs in food comprise dissolution of lipophilic additives, stabilization of nutrients and biologically active compounds, using as an antimicrobial agent and to maximize the efficiency of food preservatives. This work consists of a literature review focusing on composition and physical and chemical characteristics of microemulsions. Despite the small number of studies on the subject reported in the literature, we demonstrate some potential applications of MEs in food chemistry.

Models, truth and realism: assessing Bas van Fraassen's views on scientific representation

This paper is devoted to an analysis of some aspects of Bas van Fraassen's views on representation. While I agree with most of his claims, I disagree on the following three issues. Firstly, I contend that some isomorphism (or at least homomorphism) between the representor and what is represented is a universal necessary condition for the success of any representation, even in the case of misrepresentation. Secondly, I argue that the so-called "semantic" or "model-theoretic" construal of theories does not give proper due to the role played by true propositions in successful representing practices. Thirdly, I attempt to show that the force of van Fraassen's pragmatic - and antirealist - "dissolution" of the "loss of reality objection" loses its bite when we realize that our cognitive contact with real phenomena is achieved not by representing but by expressing true propositions about them.

Queimaduras autoinfligidas: tentativa de suicídio

OBJETIVO: Analisar a incidência, características, conduta e taxa de mortalidade de pacientes com autolesão por queimaduras internados no Centro de Queimaduras de Brasília, Distrito Federal, Brasil. MÉTODOS: Os pacientes do estudo consistiram das vítimas de queimaduras consecutivamente internadas na Unidade de Queimados do Hospital Regional da Asa Norte, Brasília, Distrito Federal, Brasil, durante o período de fevereiro de 2008 e fevereiro de 2009. Os dados foram obtidos na admissão e foram registrados prospectivamente durante a internação. Os pacientes foram seguidos até a alta ou o óbito. RESULTADOS: No período do estudo, foram admitidos 15 casos de autolesão por queimaduras na Unidade de Queimados. A média de idade foi 38,0 ± 20,6 anos; 66,7% dos casos de autolesão por queimadura eram mulheres. Na maioria dos casos eram casadas, provedoras do lar, e pobres. O maior motivo foi conflito conjugal. A taxa de mortalidade foi 40%. A área média de superfície corporal queimada foi 38,7 ± 26,1%. O álcool foi usado por 66,7% dos pacientes como causa das queimaduras. A média de duração do tratamento foi 20,1 ± 14,8 dias. Pacientes com autoinjúria por queimadura apresentaram lesões mais extensas, permaneceram mais tempo no hospital e pior prognóstico. CONCLUSÃO: Pacientes com autolesão por queimaduras apresentaram média de idade mais elevada, maior superfície corporal queimada, maior período de internação, mais complicações infecciosas e maior taxa de letalidade do que os pacientes com queimaduras acidentais. Esses pacientes precisam de constante suporte psiquiátrico, o qual pode ser útil na prevenção de futuros episódios de autoagressão.

Avaliação das condições de saúde das mulheres em uma unidade de atendimento primário no Rio Grande do Sul

Objetivos: realizar um censo sobre as condições de saúde das mulheres com idade entre 20 e 49 anos residentes na Vila Santos Dumont, Pelotas, RS. Métodos: utilizaram-se questionários padronizados para obtenção de informações sobre idade, escolaridade, vida conjugal e utilização de serviços de saúde (pré-natal, prevenção do câncer ginecológico e métodos contraceptivos). Resultados: entre as 411 mulheres entrevistadas, 343 (83,5%) haviam consultado médico no último ano. No momento do estudo, 18 (4,4%) mulheres estavam grávidas. Verificou-se que 80% das mulheres tinham exame citopatológico realizado nos últimos 3 anos e que 47,4% das mulheres tiveram suas mamas examinadas no último ano. Entre as 279 usuárias de métodos contraceptivos, 62,4% utilizavam anticoncepcionais orais, 14,0% ligadura tubária e 7,9% usavam DIU. Conclusões: este estudo incorporou o método epidemiológico ao serviço para que a partir do aprimoramento de processos, cuja efetividade até o momento é incontroversa na literatura médica, se possa produzir melhores resultados nas condições de saúde da população.

Lesões induzidas por papilomavírus humano em parceiros de mulheres com neoplasia intra-epitelial do trato genital inferior

RESUMO Objetivos: pesquisar a presença de lesões induzidas por papilomavírus (HPV) e os fatores associados em parceiros de mulheres com neoplasia intra-epitelial genital. Métodos: foram avaliados 337 homens por meio de citologia uretral, peniscopia e biópsia, quando necessário. Analisou-se a presença de lesão induzida por HPV correlacionando-a com a idade, escolaridade, tabagismo, estabilidade conjugal, início da atividade sexual, número de parceiras, antecedente de doença sexualmente transmissível (DST), postectomia, imagens peniscópicas e grau das lesões nas mulheres. Resultados: a peniscopia foi positiva em 144 homens (42,7%) e 105 (31,2%) apresentaram lesões induzidas por HPV. Somente o tabagismo, a estabilidade conjugal menor ou igual a seis meses e o antecedente de mais de uma parceira sexual estiveram associados com a presença de lesão induzida por HPV (p<0,05). A citologia uretral foi suspeita para HPV em 4,2% dos casos, sendo este achado significativamente associado com tabagismo, peniscopia ou biópsias positivas e com parceiros de mulheres com lesão de alto grau. Das 229 biópsias realizadas, 72,1% foram positivas para HPV, independentemente da imagem peniscópica e do grau de lesão na mulher. Conclusões: as lesões induzidas por HPV foram diagnosticadas em 31,2% dos casos e estiveram associadas com o tabagismo, tempo de união conjugal menor ou igual a seis meses e mais de uma parceira sexual. O grau de lesão na mulher, escolaridade, antecedente de DST, postectomia e imagem peniscópica não se mostraram correlacionados com a presença de lesão induzida por HPV.