L. A. P. Freitas

Microencapsulation of B. lactis (BI 01) and L. acidophilus (LAC 4) by Complex Coacervation Followed by Spouted-Bed Drying

Microcapsules containing B. lactis and L. acidophilus were produced by complex coacervation and spouted bed dehydrated afterwards. The aim of this study was to evaluate the resistance of these microorganisms in face of the dehydration process, shelf life, and in vitro tolerance to acid pH besides microcapsules and particles morphology by optical microscopic and SEM. The processes of complex coacervation, drying, and formation of the casein/pectin complex were adjusted to microencapsulate L. acidophilus and B. lactis, but were not efficient in protecting these organisms at pH values similar to those of the human stomach. The microorganisms maintained greater viability at a storage temperature of 7°C.

A quantitative method for the analysis of xanthine alkaloids in Paullinia cupana (guarana) by capillary column gas chromatography

The aim of the present study was to develop a capillary gas chromatography method for the quantitative analysis of caffeine in Brazilian guarana as seed powder, dried crude ethanol extracts, and lyophilized water extracts with the addition of 7β-Hydroxyethyltheophylline as the internal standard. The experimental protocol, the conditions, the analytical instrumentation, the recovery studies, as well as the analysis of seven different commercial batches of guarana, are presented and discussed.

HYDRODYNAMICS AND STABILITYOF SLOT-RECTANGULAR SPOUTED BEDS. PART I: THIN BED

Spouted beds of rectangular cross-section with gas entry through bottom slots have been proposed as a means of overcoming scale-up difficulties of conventional spouted beds. A study was undertaken of bed hydrodynamics in a thin slot-rectangular column of width 150 mm and slot width 2 to 20 mm for four types of particles. Flow regimes and bed hydrodynamics are qualitatively similar to those in cylindrical spouted beds, but there are significant quantitative differences caused by the different geometry. Slot width exerts a strong influence on such features as flow regimes, maximum spoutable bed height, minimum spouting velocity, pressure drop and fountain height.

HYDRODYNAMICS AND STABILITY OF SLOT-RECTANGULAR SPOUTED BEDS PART II: INCREASING BED THICKNESS

Tests were carried out with rectangular spouted bed columns of different thickness, i.e., front-to-back dimension, while holding the column width and air-entry slot width constant, to investigate the effects on spoul stability and bed hydrodynamics. For the three sizes of glass beads and one size of polyethylene beads examined, increasing the column thickness led to three-dimensional effects, such as formation of multiple spouts, and affected such hydrodynamics variables as the minimum spouting velocity, maximum spoutable bed depth and maximum pressure drop.

Drying of Pharmaceuticals: The Applicability of Spouted Beds

ABSTRACT This study evaluates the performance of conventional spouted beds (CSB) with inert bodies in the drying of pharmaceutical pastes, based on the dry product quality. The powder obtained by drying annatto extracts shows properties comparable to one of the commercial products, indicating that the spouting is competitive with other industrial and lab-scale processes. The contents of bixin and caffeine in annatto and guarana dry powders demonstrated a strong dependence on the inlet air temperature. Also, the properties of indomethacin-containing microcapsules dried in CSB and spray dryers revealed that spouting is a promising technique to obtain pharmaceutical forms with unique drug release qualities.

The Preparation of Ternary Solid Dispersions of an Herbal Drug via Spray Drying of Liquid Feed

The present study aimed the preparation and characterization of ternary solid dispersions by direct spray drying of a liquid suspension containing curcumin, a solubility enhancer and a drying aid. The experiments followed a Box-Behnken design in order to evaluate the influence of temperature, ratio of curcumin: lipidic carrier, and the collodial silicon dioxide content on the characteristics of the microparticulated solid dispersions. The angle of repose, Hausner factor, Carr index, water activity, and solubility were used to characterize solid dispersions. The results show that water activity, Hausner factor, and Carr index varied in an acceptable range for pharmaceutical purposes. The condition that maximizes solubility was determined using an exploratory design based on a surface response analysis and allowed a 3200-fold increase in curcumin solubility. Ternary solid dispersion showed a 90% curcumin release after 10 min during a dissolution test. The results show that the spray drying of a liquid feed is an attractive and promising alternative to obtain enhanced solubility drug ternary solid dispersions.

Curcumin reduces cisplatin-induced neurotoxicity in NGF-differentiated PC12 cells

The potential neuroprotective benefits of curcumin against cisplatin neurotoxicity were investigated. Curcumin is a polyphenol derived from the rhizome of Curcuma longa whose pharmacological effects include antioxidant, anti-inflammatory and anti-cancer properties. Cisplatin is a potent chemotherapeutic drug with activity against a wide variety of tumors, although it has notorious side effects. Cisplatin neurotoxicity is clinically evident in patients that have undergone a full course of chemotherapy and develop a peripheral neuropathy that may affect the treatment regimen and the patients qualify of life. In this study, we examined whether curcumin can protect against cisplatin neurite outgrowth inhibition in PC12 cells, which is an indicator of the protective potential against neuropathy. We also investigated whether curcumin affects cisplatin effectiveness by analyzing the modulation of p53 gene expression and its effect on cisplatin cytotoxicity in HepG2 tumor cells. Non-cytotoxic concentrations of curcumin reduced in vitro neurotoxicity of cisplatin in PC12 cells. The treatment of PC12 cells with cisplatin (10μg/mL) significantly reduced neurite outgrowth. The tested concentration of curcumin (1.0 and 10μg/mL) did not result in neurite toxicity but nevertheless diminished cisplatin-induced inhibition of neurite outgrowth by up to 50% (p<0.05). Our results indicate that curcumin does not compromise cisplatins anticancer activity. Curcumin neither suppressed p53 mRNA transcription nor protected tumor cells against cisplatin cytotoxicity. These results indicate that curcumin may reduce cisplatin-induced neurotoxicity, and clinical studies should potentially be considered.

Heat transfer in a draft tube spouted bed with bottom solids feed

Abstract Detailed temperature measurements were obtained for a draft tube spouted bed of 2.6-mm glass beads with bottom solids feed at different air flow rates, air inlet temperatures, solids feed rates and bed heights. The temperature profiles showed that air temperature drops significantly with the axial position in the spout, while air and solids temperatures are uniform in the annulus. The drop in air temperature along the spout decreases with increasing air flow rate and increases with solids feed rate. A model was adapted for use with the spouted bed configuration studied here and its predictions were compared with the experimental data. In general, the model could accurately predict the temperature profiles in the bed, since the largest deviations were observed for the air temperature in the spout and were always less than 5%. Although the model provided for a low deviation in predictions, air temperature in the spout was systematically over-estimated.

Chitosan microparticles for sustaining the topical delivery of minoxidil sulphate

Given the hypothesis that microparticles can penetrate the skin barrier along the transfollicular route, this work aimed to obtain and characterise chitosan microparticles loaded with minoxidil sulphate (MXS) and to study their ability to sustain the release of the drug, attempting a further application utilising them in a targeted delivery system for the topical treatment of alopecia. Chitosan microparticles, containing different proportions of MXS/polymer, were prepared by spray drying and were characterised by yield, encapsulation efficiency, size and morphology. Microparticles selected for further studies showed high encapsulation efficiency (∼82%), a mean diameter of 3.0 µm and a spherical morphology without porosities. When suspended in an ethanol/water solution, chitosan microparticles underwent instantaneous swelling, increasing their mean diameter by 90%. Release studies revealed that the chitosan microparticles were able to sustain about three times the release rate of MXS. This feature, combined with suitable size, confers to these microparticles the potential to target and improve topical therapy of alopecia with minoxidil.

Spray Congealing of Pharmaceuticals: Study on Production of Solid Dispersions Using Box-Behnken Design

This work aimed at evaluating the spray congealing method for the production of microparticles of carbamazepine combined with a polyoxylglyceride carrier. In addition, the influence of the spray congealing conditions on the improvement of drug solubility was investigated using a three-factor, three-level Box-Behnken design. The factors studied were the cooling air flow rate, atomizing pressure, and molten dispersion feed rate. Dependent variables were the yield, solubility, encapsulation efficiency, particle size, water activity, and flow properties. Statistical analysis showed that only the yield was affected by the factors studied. The characteristics of the microparticles were evaluated using X-ray powder diffraction, scanning electron microscopy, differential scanning calorimetry, and hot-stage microscopy. The results showed a spherical morphology and changes in the crystalline state of the drug. The microparticles were obtained with good yields and encapsulation efficiencies, which ranged from 50 to 80% and 99.5 to 112%, respectively. The average size of the microparticles ranged from 17.7 to 39.4 µm, the water activities were always below 0.5, and flowability was good to moderate. Both the solubility and dissolution rate of carbamazepine from the spray congealed microparticles were remarkably improved. The carbamazepine solubility showed a threefold increase and dissolution profile showed a twofold increase after 60 min compared to the raw drug. The Box-Behnken fractional factorial design proved to be a powerful tool to identify the best conditions for the manufacture of solid dispersion microparticles by spray congealing.