Thermal study and physico-chemical characterization of some functional properties of guava seeds protein isolate (Psidium guajava)

The guava seed protein isolate ( PI) was obtained from the protein precipitation belonging to the class of the gluteline (Ip 4.5). The conditions for the preparation of the PI were determined by both the solubility curve and simultaneous thermogravimetry-differential thermal analysis (TG-DTA): pH 11.5, absence of NaCl and whiteners and T=( 25 +/- 3) degrees C. Under these conditions a yield of 77.0 +/- 0.4%, protein content of 94.2 +/- 0.3, ashes 0.50 +/- 0.05% and thermal stability, T= 200 degrees C, were obtained. The TG-DTA curves and the PI emulsification capacity study showed the presence of hydrophobic microdomains at pH 11.5 and 3.0 suggesting a random coil protein conformation and, to pH 10.0, an open protein conformation. The capacity of emulsification (CE), in the absence of NaCl, was verified for: 1 - pH 3.0 and 8.5, using the IP extracted at pH 10.0 and 11.5, CE >= 343 +/- 5 g of emulsified oil/g of protein; 2 - pH 6.60 just for the PI obtained at pH 11.5, CE >= 140 +/- 8 g of emulsified oil/g of protein.

Preparation and characterisation of Dextran-70 hydrogel for controlled release of praziquantel

Um hidrogel foi desenvolvido a partir de dextrano 70 kDa (DEX-70) e praziquantel incorporado (PZQ) como fármaco modelo. Propriedades biofarmacêuticas, como solubilidade e velocidade de dissolução, foram analisadas no desenvolvimento do hidrogel. Além disso, o hidrogel também foi caracterizado por espectroscopia na região do infravermelho e calorimetria diferencial exploratória (DSC). Testes da taxa de intumescimento mostraram que o hidrogel intumesce lentamente, embora tenha sido mais rápido do que a taxa do polímero livre. Nos testes de dissolução, o hidrogel liberou o fármaco lenta e continuamente. Esta liberação lenta foi semelhante a observada nos testes de intumescimento e resultou em uma liberação controlada do fármaco. Assim, o dextrano 70 kDa é um polímero adequado para o desenvolvimento de hidrogéis como veículos para a liberação controlada de fármacos.

LC Evaluation of Intestinal Transport of Praziquantel

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A new approach to the granulation of beta-cyclodextrin inclusion complexes

Cyclodextrins (CDs) are annular oligosaccharides containing 6-12 glucose unities joined together by alpha-1,4 bonds. They have a conical-truncated shape with a lipophilic cavity in which different molecules can be included resulting in a stable inclusion complex. The cyclodextrins have been widely applied in pharmaceutical technology with the objective of increasing the solubility, stability and bioavailability of drugs in different pharmaceutical dosage forms, such as tablets. In order to obtain beta-CD tablets, liquid dispersions of drug/beta-CD are usually submitted to different drying processes, like spray-drying, freeze-drying or slow evaporation, being this dry material added to a number of excipients. However, such drying processes can generate particulate materials showing problems of flow and compressibility, needing their conversion into granulates by means of wetting with granulation liquid followed by additional drying. In this work, the main objective was to evaluate the preparation of tablets without the need of this additional drying step. For this purpose an aqueous dispersion containing acetaminophen/beta-CD complex and cornstarch was dried using a spouted bed and the obtained granules were compressed in tablets. Acetaminophen was used as model drug due to its low water solubility and the inexpensive and widely available cornstarch was chosen as excipient. Acetaminophen powder was added into a beta-cyclodextrin solution prepared in distilled water at 70 degrees C. Stirring was kept until this dispersion cooled to room temperature. Then cornstarch was added and the resulting dispersion was dried in spouted bed equipment. This material was compressed into tablets using an Erweka Korsh EKO tablet machine. This innovative approach allowed the tablets preparation process to be carried out with fewer steps and represents a technological reliable strategy to produce beta-cyclodextrin inclusion complexes tablets. (C) 2010 Elsevier By. All rights reserved.

Chitosan-pectin multiparticulate systems associated with enteric polymers for colonic drug delivery

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

A discriminating dissolution method for glimepiride polymorphs

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analysis of the molecular association of rifampicin with hydroxypropyl-²-cyclodextrin

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Pressure drop correlation for oil-refrigerant R134a mixture flashing flow in a small diameter tube

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of the addition of soy lecithin and Yucca schidigera extract on the properties of gelatin and glycerol based biodegradable films

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Produção de biscoitos extrusados de polvilho azedo com fibras: efeito de parâmetros operacionais sobre as propriedades físicas

Neste trabalho buscou-se avaliar o efeito de parâmetros operacionais do processo de extrusão no desenvolvimento de biscoitos de polvilho com fibras, utilizando como matérias-primas o polvilho azedo e o farelo de mandioca. O processamento foi realizado em um extrusor mono-rosca, sendo considerados parâmetros variáveis: temperatura na 3ª zona de extrusão, umidade e porcentagem de fibras na mistura. Para analisar o efeito combinado das variáveis independentes nas características tecnológicas dos extrusados, utilizou-se o delineamento 'central composto rotacional' para três fatores. Os resultados obtidos mostraram efeitos significativos da umidade e porcentagem de fibras sobre o volume específico, sendo que a temperatura afetou os índices de solubilidade e absorção de água dos produtos extrusados. Condições de baixa temperatura (65 °C), baixa umidade (12%) e baixo teor de fibras (<4%), nas condições de processo utilizadas, produzem biscoitos com boas características tecnológicas.

Efeito dos parâmetros de extrusão sobre as propriedades funcionais de extrusados da farinha de batata-doce

Farinha de batata-doce (Ipomoea batatas) foi extrusada em equipamento de rosca simples, mantendo-se fixas as temperaturas na 1ª e 2ª zonas de extrusão (20ºC e 60ºC, respectivamente). O efeito das variáveis umidade da farinha (15, 18 e 21%), temperatura na 3ª zona (100, 120 e 140ºC) e rotação da rosca (180, 210 e 240 rpm) sobre as características dos extrusados foi investigado utilizando-se metodologia de superfície de resposta. O teor de umidade e a temperatura de extrusão influenciaram significativamente a expansão dos extrusados. O índice de expansão apresentou valores crescentes com a temperatura sob baixos teores de umidade. A dureza dos extrusados e também o índice de absorção de água e o índice de solubilidade em água das farinhas extrusadas não mostraram modelo de regressão significativo com as condições de processo. Quanto à cor das farinhas, o componente L* (luminosidade) apresentou valores crescentes e o parâmetro a*, valores decrescentes com a elevação do teor de umidade até 20-21%. O parâmetro b* e a diferença de cor entre farinhas extrusadas e não extrusadas mostraram valores decrescentes com o aumento da umidade.

Porcentagens de saponinas e taninos em vinte e oito cultivares de alfafa (Medicago sativa L.) em duas épocas de corte - Botucatu - SP

O objetivo do estudo foi determinar os conteúdos de saponinas, taninos e a solubilidade da proteína (SP) de 28 cultivares de alfafa: Crioula, Monarca, BR 4, Alto Great, MH 4, SW 9210 A, 5929, BR 1, EL Grande, 5715, MH 15, Valley Plus, BR 2, Rio, SW 8210, Maricopa, ICI 990, 5888, P 30, Alfa-200, WL 516, SW 8112 A, BR 3, Florida 77, Araucana, Falcon, Semit 921 e Sutter. O material analisado foi obtido do 10º e 14º corte, respectivamente; em 08/12/97 e 16/04/98, de um experimento desenvolvido na Faculdade de Medicina Veterinária e Zootecnia, UNESP, Botucatu. Amostras de cada cultivar foram colhidas, pesadas e secas em estufa a 52ºC. As saponinas foram extraídas com solvente hidrofílico e lipofílico e o conteúdo foi calculado pela equação y=0,8121x-1,4759, R² = 1,00. A extração dos taninos totais e condensados foi efetuada por meio de ultra-som (12 min), sendo os taninos totais determinados pela equação: y=44,978 + 0,5644 com R²=0,9977 e os condensados, multiplicando-se a absorbância por 78,26 dividido pelo teor de matéria seca. A SP foi determinada pelo método de KOH, de acordo com a seguinte fórmula: SP (%) = proteína solúvel x 100/proteína bruta da amostra. Os teores de saponinas, taninos totais e condensados e a solubilidade da proteína não diferiram (P>0,05) entre as cultivares. Houve efeito (P<0,05) da época de corte apenas sobre o teor de taninos totais. Os teores médios de saponinas de 1,00% aliados à baixa solubilidade média da proteína bruta (34,11%) não se constituem em fatores limitantes para uso dos cultivares de alfafa estudadas.

Effect of Iron II on Hydroxyapatite Dissolution and Precipitation in vitro

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Slow-release fluoride devices: a literature review

Although the prevalence of caries has decreased dramatically over the past decades, it has become a polarised disease, with most of subjects presenting low caries levels and few individuals accounting for most of the caries affected surfaces. Thus it become evident for the need of clinical approaches directed at these high-risk patients, in order to overcome problems related to compliance and low attendance at dental care centres. Slow-release fluoride devices were developed based on the inverse relationship existing between intra-oral fluoride levels and dental caries experience. The two main types of slow-release devices - copolymer membrane type and glass bead - are addressed in the present review. A substantial number of studies have demonstrated that these devices are effective in raising intra-oral F concentrations at levels able to reduce enamel solubility, resulting in a caries-protective effect. Studies in animals and humans demonstrated that the use of these devices was able to also protect the occlusal surfaces, not normally protected by conventional fluoride regimens. However, retention rates have been shown to be the main problem related to these devices and still requires further improvements. Although the results of these studies are very promising, further randomised clinical trials are needed in order to validate the use of these devices in clinical practice. The concept of continuously providing low levels of intra-oral fluoride has great potential for caries prevention in high caries-risk groups.

Evaluation of the physical and chemical properties of two commercial and three experimental root-end filling materials

Objective. The aim of this study was to evaluate the pH, calcium release, setting time, and solubility of two commercially available mineral trioxide aggregate (MTA) cements (white MTA Angelus and MTA Bio), and of three experimental cements (light-cured MTA, Portland cement with 20% bismuth oxide and 5% calcium sulfate, and an epoxy resin-based cement).Study design. For evaluation of pH and calcium ion release, polyethylene tubes with 1.0 mm internal diameter and 10.0 mm length were filled with the cements and immediately immersed in flasks containing 10 mL deionized water. After 3, 24, 72, and 168 hours, the tubes were removed and the water from the previous container was measured for its pH and calcium content with a pH meter and an atomic absorption spectrophotometer. For analysis of the setting time, Gilmore needles weighing 100 g and 456.5 g were used, in accordance with the American Society for Testing and Materials specification no. C266-03. Solubility of each cement was also tested.Results. All the cements were alkaline and released calcium ions, with a declining trend over time. After 3 hours, Portland cement + bismuth oxide and MTA Bio had the highest pH and light-cured MTA the lowest. After 1 week, MTA Bio had the highest pH and light-cured MTA and epoxy resin-based cement the lowest. Regarding calcium ion release, after 3 hours, Portland cement + bismuth oxide showed the highest release. After 1 week, MTA Bio had the highest. Epoxy resin-based cement and light-cured MTA had the lowest calcium release in all evaluation periods. Regarding setting times, white MTA Angelus and MTA Bio had the shortest, Portland cement + bismuth oxide had an intermediate setting time, and the epoxy resin-based cement had the longest. The materials that showed the lowest solubility values were the epoxy resin-based cement, Portland cement + bismuth oxide, and light-cured MTA. The highest solubility values were presented in white MTA Angelus and MTA Bio.Conclusions. The white MTA Angelus and MTA Bio had the shortest setting times, higher pH and calcium ion release, and the highest solubility. In contrast, the epoxy resin-based cement and light-cured MTA showed lower values of solubility, pH, and calcium ion release. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2010; 110: 250-256)