Luiz Alberto Lira Soares

Dry granulation and compression of spray-dried plant extracts

The purpose of this research was to evaluate the influence of dry granulation parameters on granule and tablet properties of spray-dried extract (SDE) fromMaytenus ilicifolia, which is widely used in Brazil in the treatment of gastric disorders. The compressional behavior of the SDE and granules of the SDE was characterized by Heckel plots. The tablet properties of powders, granules, and formulations containing a high extract dose were compared. The SDE was blended with 2% magnesium stearate and 1% colloidal silicon dioxide and compacted to produce granules after slugging or roll compaction. The influences of the granulation process and the roll compaction force on the technological properties of the granules were studied. The flowability and density of spray-dried particles were improved after granulation. Tablets produced by direct compression of granules showed lower crushing strength than the ones obtained from nongranulated material. The compressional analysis by Heckel plots revealed that the SDE undergoes plastic deformation with a very low tendency to rearrangement at an early stage of compression. On the other hand, the granules showed an intensive rearrangement as a consequence of fragmentation and rebounding. However, when the compaction pressure was increased, the granules showed plastic deformation. The mean yield pressure values showed that both granulation techniques and the roll compaction force were able to reduce the materials ability to undergo plastic deformation. Finally, the tablet containing a high dose of granules showed a close dependence between crushing strength and the densification degree of the granules (ie, roll compaction force).

Optimization of tablets containing a high dose of spray-dried plant extract: A technical note

ConclusionsOptimization of CSD and CMC-Na in tablet formulations containing a high dose of SDE fromM ilicifolia was performed by central composite design (CCD) and response surface methodology (RSM). The study demonstrated that CSD affected mainly the hardness and friability, while CMC-Na modified the disintegration times. The optimum formula for minimum disintegration time and friability, and maximum crushing strength, was found to contain 1.2% (wt/wt) of CSD and 5.0% (wt/wt) of CMC-Na. At these conditions, the tablet shows a crushing strength of 107.9 N, a friability of 0.56% (wt/wt), and a maximum disintegration time of 6.8 minutes.

Micro-emultocrit technique: a valuable tool for determination of critical HLB value of emulsions.

The aim of this work was to develop a methodology for rapid determination of the critical hydrophilic-lipophilic balance (HLB) value of lipophilic fractions of emulsions. The emulsions were prepared by the spontaneous emulsification process with HLB value from 4.3 to 16.7. The preparations were stored at 2 different temperatures (25°C and 4°C) and their physicochemical behavior was evaluated by the micro-emultocrit technique and the long-term stability study. The experimental data show a reverse relationship between HLB values of the surfactant mixtures and emulsion stability. A close correlation between the results for both stability procedures was observed, suggesting the use of micro-emultocrit to predict stabilities of such systems. In addition, it was found that the critical HLB of the Mygliol 812 was 15.367.The aim of this work was to develop a methodology for rapid determination of the critical hydrophilic-lipophilic balance (HLB) value of lipophilic fractions of emulsions. The emulsions were prepared by the spontaneous emulsification process with HLB value from 4.3 to 16.7. The preparations were stored at 2 different temperatures (25°C and 4°C) and their physicochemical behavior was evaluated by the micro-emultocrit technique and the long-term stability study. The experimental data show a reverse relationship between HLB values of the surfactant mixtures and emulsion stability. A close correlation between the results for both stability procedures was observed, suggesting the use of micro-emultocrit to predict stabilities of such systems. In addition, it was found that the critical HLB of the Mygliol 812 was 15.367.

Total Flavonoids Content in the Raw Material and Aqueous Extractives from Bauhinia monandra Kurz (Caesalpiniaceae)

The aim of this work was to evaluate the spectrophotometric methodology for determining the total flavonoid content (TFC) in herbal drug and derived products from Bauhinia monandra Kurz. Several analytical parameters from this method grounded on the complex formed between flavonoids and AlCl3 were evaluated such as herbal amount (0.25 to 1.25 g); solvent composition (ethanol 40 to 80%, v/v); as well as the reaction time and AlCl3 concentration (2 to 9%, w/v). The method was adjusted to aqueous extractives and its performance studied through precision, linearity and preliminary robustness. The results showed an important dependence of the method response from reaction time, AlCl3 concentration, sample amount, and solvent mixture. After choosing the optimized condition, the method was applied for the matrixes (herbal material and extractives), showing precision lower than 5% (for both parameters repeatability and intermediate precision), coefficient of determination higher than 0.99, and no important influence could be observed for slight variations from wavelength or AlCl3 concentration. Thus, it could be concluded that the evaluated analytical procedure was suitable to quantify the total flavonoid content in raw material and aqueous extractives from leaves of B. monandra.

Influence of the Lipophilic External Phase Composition on the Preparation and Characterization of Xylan Microcapsules—A Technical Note

Scientific studies on new drug delivery systems have significantly increased in the past few years and this growth is expected to continue in the near future (1). Such systems are of great interest because of their ability to improve drug performance in terms of efficacy, safety, and patient compliance (1). In many cases, conventional drug delivery provides an increase of drug concentration at potentially toxic levels (2). Additionally, the need for delivering drugs with fewer side effects has prompted the development of new drug delivery systems (1). Xylan is the second most abundant polymer found in hardwoods and annual plants (3), particularly in agricultural residues such as grain hulls, corn cobs, and corn stalks (4). Depending on the botanical source, the backbone chemical structure may vary. However, the majority of xylans present side chains of different sugars such as 4-O-methyl-d-glucoronic acid, O-acetyl-l-arabinose, l-arabinose, and d-glucoronic acid bond by a glycosidic linkage to the backbone (3). Because of its complex structure, the complete degradation of xylan requires the activity of several enzymes which are specifically produced by human colonic microflora (5). Therefore, xylan microcapsules may represent a novel and promising colon-specific drug delivery system. Microcapsules based on natural polymers may be produced by means of a variety of methods. Emulsion solvent extraction, emulsion solvent evaporation and interfacial cross-linking polymerization are the most commonly employed processes for the production of microcapsules (4). One of the critical parameters in the microencapsulation process is the external phase used in the emulsification step (6). In fact, the external phase can influence the microcapsules morphology, their aggregation state, and mainly the release of the microencapsulated active compound (7). Because the production of xylan-based microcapsules is a subject barely studied by scientists worldwide, the aim of this work was to evaluate the influence of the lipophilic external phase composition on the production and mean particle size of xylan microcapsules produced by interfacial cross-linking polymerization.

Phytochemical and Antibacterial Investigations of the Extracts and Fractions from the Stem Bark of Hymenaea stigonocarpa Mart. ex Hayne and Effect on Ultrastructure of Staphylococcus aureus Induced by Hydroalcoholic Extract

The aim of this study was to investigate the antimicrobial activity of different extracts and fractions obtained from Hymenaea stigonocarpa stem barks. The cyclohexanic, ethyl acetate, ethanol, aqueous, and hydroalcoholic extracts were obtained by maceration. The hydroalcoholic extract was partitioned, which resulted in the ethyl acetate and aqueous fractions. All extracts and fractions were subjected to phytochemical screening and evaluation of total phenol and tannin contents. An HPLC-DAD and ultrastructural alterations analysis were performed. Terpenes and coumarins were detected in the cyclohexanic extract. Flavonoids and condensed tannins were present in the other extracts and fractions. The extracts with the highest contents of tannins, ethanol (EE), hydroalcoholic (HE), and aqueous fraction (AF) showed also the highest antimicrobial activity. The MIC values ranged from 64 to 526 µg/mL. The chromatographic fingerprints suggest the presence of astilbin and other flavonoids in EE and HE. Presence of the thick cell wall, undulating outer layer, abnormal septa, and leakage of the cytoplasmic contents and absence of cell wall and cell lyses were the main alterations observed on Staphylococcus aureus ATCC 33591 after treatment with the Hymenaea stigonocarpa hydroalcoholic extract. The presence of phenolic compounds like flavonoids and tannins is possibly the reason for the antimicrobial activity.

Agitation during lipoplex formation harmonizes the interaction of siRNA to cationic liposomes.

We recently demonstrated that agitation during lipoplex formation (vorLTsiR) improves the gene knockdown effect of siRNA because the resultant decrease in lipoplex size leads to an enhanced uptake by cells. In furthering this line of research, the present study was focused on the interaction of siRNA to cationic liposomes during lipoplex preparation. A fluorescence resonance energy transfer (FRET) study indicated that the application of agitation in the presence of siRNA effectively reorganized positively charged lipids (DC-6-14 and DOPE) in an order that effectively promoted further electrostatic interaction between the negatively charged phosphate backbone of siRNA and the positively charged lipids in the cationic liposome membrane. A circular dichroism (CD) study indicated that the agitation did not bring about a change in the A-form helix of siRNA, therefore the interactions between the lateral anionic groups of siRNA - responsible for the characteristic bands of the A-form helix - and cationic liposomes were effectively promoted. Factorial design coupled with response surface methodology was used to statistically analyze the influence of vortex speed and time and siRNA dose on the in vitro gene knockdown effects of siRNA-lipoplex that were spontaneously formulated (spoLTsiR) along with that formulated under agitation (vorLTsiR). The analysis indicated that vortex speed plays the most important role in enhancing the gene knockdown effect of siRNA among the three variables, although all three are important. It was concluded that the high energy transmitted by applying agitation during lipoplex formation harmonized the interaction of siRNA to positively charged lipids (DC-6-14 and DOPE) in cationic liposomes, resulting in a superior gene knockdown efficacy of vorLTsiR compared to spoLTsiR. Our study suggests that the preparation procedure is one of the critical factors in producing the enhanced gene knockdown effect of siRNA.

Development and optimization of extractives from Astronium urundeuva (allemão) Engl. by factorial design

O objetivo deste trabalho foi avaliar as influencias de variaveis de preparacao de macerados das cascas de Astronium urundeuva sobre residuo seco e teor de taninos totais. Desta forma, um desenho fatorial do tipo 32 foi empregado para avaliar a importância da proporcao de planta (10, 15 e 20 %; m/v) e da concentracao de etanol (40, 60 e 80 %; v/v) sobre as respostas eleitas. Modelos matematicos foram ajustados aos dados experimentais. As equacoes validadas foram usadas para gerar superficies de respostas. A analise das superficies demonstrou que as condicoes otimas para obtencao de preparacoes extrativas com elevada eficiencia extrativa de taninos foram: 10 % (m/v) para planta e etanol 40 % (v/v) como solvente.

Spray-dried extract of Phyllanthus niruri L. reduces mucosal damage in rats with intestinal inflammation

Phyllanthus niruri L. belongs to the Euphorbiaceae, and is known by the common name of ‘stonebreaker’ in Brazil. Some species within the Phyllanthus genus are widely used in traditional medicine to counteract different types of anti‐inflammatory diseases.

Growth inhibitory effects of Phyllanthus niruri extracts in combination with cisplatin on cancer cell lines.

AIM To investigate the cytotoxic effects of spray-dried extracts of Phyllanthus niruri in combination with cisplatin on two cancer cell lines. METHODS Colorectal carcinoma (HT29) and human hepatocellular carcinoma (HepG2) cells were treated with spray-dried extracts of Phyllanthus niruri (SDEPN) either alone or in combination with cisplatin at different concentrations (0.5 mg/mL and 1 mg/mL) for 4 h and 24 h. To verify and quantify cancer cells treated with these products as well as identify the cell cycle stage and cell viability, we stained the cells with propidium iodide and assessed them by flow cytometry. The percentage of cells in different cell cycle phases was quantified and data were expressed as histograms. Significant differences between groups were determined using analysis of variance and Bonferronis test, as indicated. A value of P < 0.05 was considered to be statistically significant. RESULTS SDEPN had significantly different cytotoxic effects on HT29 (2.81 ± 0.11 vs 3.51 ± 1.13, P > 0.05) and HepG2 (5.07 ± 0.3 vs 15.9 ± 1.04, P < 0.001) cells when compared to control cells for 4 h. SDEPN also had significantly different cytotoxic effects on HT29 (1.91 ± 0.57 vs 4.53 ± 1.22, P > 0.05) and HepG2 (14.56 ± 1.6 vs 35.67 ± 3.94, P < 0.001) cells when compared to control cells for 24 h. Both cell lines were killed by cisplatin in a dose-dependent manner compared to control cells (HepG2 cells for 4 h: 10.78 ± 1.58 vs 53.89 ± 1.53, P < 0.001; 24 h: 8.9 ± 1.43 vs 62.78 ± 1.87, P < 0.001 and HT29 cells for 4 h: 9.52 ± 0.913 vs 49.86 ± 2.89, P < 0.001; 24 h: 11.78 ± 1.05 vs 53.34 ± 2.65, P < 0.001). In HT29 cells, pretreatment with SDEPN and subsequent treatment with cisplatin resulted in a greater number of cells being killed (12.78 ± 1.01 vs 93.76 ± 1.6, P < 0.001). HepG2 cells showed significant cell killing with treatment with SDEPN when combined with cisplatin (12.87 ± 2.78 vs 78.8 ± 3.02, P < 0.001). CONCLUSION SDEPN is selectively toxic against two cancer cell lines. Moreover, SDEPN in combination with cisplatin induces a synergistic increase in the cell death of both HT29 and HepG2 cells.