Silicified microcrystalline cellulose based pellets and their physicochemical properties

Silicified microcrystalline cellulose (SMCC), Prosolv SMCC 50 was used as spheronization aid to manufacture pellets by extrusion and spheronization. Different ratios of SMCC to lactose were used to manufacture pellets using appropriate levels of water as liquid binder. Avicel PH101 based pellets were also manufactured for comparison of their physical properties. The ratio of liquid binder to spheronization aid was critical to produce pellets of desired size and shape. Extrudates composed of 20% aid could withstand only smaller spheronization force in order to be shaped into pellets. The successful products fulfilled the quality of pellets such as narrow size distribution and spherical in shape. The highest surface tensile strength was observed in pellets with equal ratio of lactose to SMCC while pellets having 20% aid disintegrated rapidly within 15 min. Furthermore, Prosolv SMCC 50 based pellets possessed a stronger surface tensile strength when compared with Avicel PH101 based pellets. In conclusion, Prosolv SMCC 50 has showed to be a good spheronization aid for extrusion and spheronization when used in the range of 20 to 80% content. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43829.     

西罗莫司自乳化缓释微丸的制备及对淋巴细胞的作用研究

采用挤出滚圆法,以羟丙甲基纤维素钠为主要骨架型缓释材料制备出西罗莫司自乳化缓释微丸,考察制备工艺中挤出速度、滚圆速度、滚圆时间对目标速率影响并对淋巴细胞作用的研究。结果表明:西罗莫司自乳化缓释微丸的目标收率为(92.8±2.51)%(n=3),采用挤出速度为挤出速度为65 r·min~(-1);滚圆速度为650 r·min~(-1);滚圆时间为3 min最适宜;西罗莫司缓释微丸能够抑制淋巴细胞的增值的活性,随着时间增长,抑制作用增强。以上表明:采用该方法为西罗莫司缓释微丸研究提供新的方法。     

Effects of Different Drying Methods on the Quality of Squid Cubes

The effects of three different drying methods (e.g., intermediate infrared-assisted convection drying, low-frequency (915 MHz) microwave drying, and hot-air drying) on the quality of squid cubes were investigated. The quality parameters used to evaluate the drying efficiency were color, shrinkage, rehydration ratio, and hardness of the final dried products. The results showed that intermediate infrared-assisted convection drying and low-frequency microwave drying have the advantages over hot-air drying in terms of drying rate, shrinkage percentage, and rehydration ratio. Low-frequency microwave-dried samples displayed a puffed structure and their hardness was the highest. The intermediate-wave infrared-assisted convection drying, at 60°C, was identified as the best method for squid-cube drying in this study.     

Mixed solvent system as binder for the production of silicified microcrystalline cellulose-based pellets

Silicified microcrystalline cellulose pellets with hydroxypropyl methylcellullose (HPMC) as modifier were prepared using a mixed solvent as liquid binder. Pellets were produced using extrusion-spheronization with a mixed solvent consisting of water and isopropanol as liquid binder. The key spheronization aid was Prosolv® SMCC 90. Low viscosity grade HPMC was incorporated aiming to modify release of indometacin. Physical characteristics including breaking load, apparent density and flow properties, particle size distribution and shape were determined. Drug loaded pellets were also tested for dissolution profiles. By adjusting liquid binder property, at isopropanol to water ratio of 3.5 to 6.5, pellets of desirable size and shape with reasonable yields were obtained. Pellets exhibited good flow property and they were mechanically strong. Pellet with higher HPMC content displayed a faster drug dissolution profile. This was because low viscosity grade HPMC was not enough to create strong gel. Instead hydration of HPMC molecules increased matrix's hydrophilicity and weakened the structure of pellet faster. The release of indometacin was partly based on the erosion of hydrated matrix. The presence of HPMC in the pellets would require a mixed solvent to produce desirable shape. Incorporation of HPMC had modified drug release from the pellets without further coating. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47924.     

Spheronization of solid lipid extrudates

The objective of this study was the examination and development of a solvent-free spheronization process as a manufacturing tool for sustained release matrix spheres. Extrudates prepared from a binary lipid mixture with different amounts of Dynasan 114® and Witocan 42/44® and theophylline as model drug were processed in systematic spheronization experiments by varying pellet formulation and spheronizer-jacket temperature. The rounding procedure of the pellets was investigated by analyzing spot samples after different processing times. The obtained pellets were characterized according to their shape, size distribution, porosity and drug release properties. Round lipid pellets with a mean aspect ratio below 1.1 and a narrow particle size distribution with median equivalent diameters around 1.5 mm could be obtained. The pellets showed sustained drug release properties and porosities below 1%. The spheronization process was shown to be strongly temperature- and formulation dependent. The material temperature during the process was influenced by the adjusted jacket temperature and friction- and shear forces between the rounded particles; control of material temperature seems to pose the challenge in the investigated process.     

Design of microcrystalline cellulose-free alginate spheroids by extrusion-spheronization technique

Conventional spheroid preparation by extrusion-spheronization technique requires microcrystalline cellulose (MCC) as processing aid to improve extrudability of wet mass and spheronization capacity of extrudates. The present study investigated formulation and processing attributes in extrusion and spheronization necessary for design of MCC-free alginate spheroids. The physicochemical characteristics of these spheroids were examined and compared against MCC-loaded alginate spheroids using chlorpheniramine maleate and tolbutamide as water-soluble and poorly water-soluble drugs respectively. Alginate spheroids demonstrated a slower release of hydrophilic drug due to ease of matrix swelling and aggregation in the absence of MCC. This reduced their specific surface area for drug dissolution. Crosslinking of alginate with soluble calcium densified the surface of spheroids and hindered matrix aggregation. It led to faster drug release from alginate than alginate-MCC spheroids. Fast drug release was also noted in spheroids embedded with hydrophobic drug when MCC was absent as drug adsorbent. A complete replacement of MCC with alginate can promote or retard drug release of spheroids as a function of drug–polymer interaction and state of matrix swelling and aggregation.     

Development of pellets of nifedipine using HPMC K15 M and κ-carrageenan as mucoadhesive sustained delivery system and in vitro evaluation

Polymeric mucoadhesive pellets of nifedipine were designed using computer software and they were prepared by extrusion-spheronization using HPMC K15M and κ-carrageenan with microcrystalline cellulose. A randomized rotatable two factor central composite design was applied for assessment of influence of two independent variables such as concentration of κ-carrageenan and HPMC K15M on dependent variables. Pellets were characterized by FTIR, DSC, SEM, flow properties, particle size, abrasion resistance, sphericity, drug content, percent production yield, in vitro drug release, ex vivo mucoadhesion, stability studies and similarity factor. The optimized formulation was selected based on criteria of sphericity nearest to 1.0 with maximum cumulative drug release percentage. Formulation NF6 exhibited sufficient porous spheres, free flowing and smooth surface mucoadhesion of 91.34 % and drug content 98.22 ± 0.37 %. Kinetic modeling revealed that the formulation followed the Higuchi model and showed the Quassi-Fickian drug release mechanism. The similarity factor, F2 value, was found to be 74 ± 6 and there was no significant change in drug content and ex vivo mucoadhesion after 90 days at 40 ± 2 °C, and 75 ± 5 % RH clearly indicated the optimized batch NF6 was stable. Thus, it can be concluded that use of κ-carrageenan, microcrystalline cellulose and HPMC K15M at the 20:35:10 w/w ratio could provide an effective carrier for enhancement of sphericity and sustained release of matrix pellets.     

2种方式干燥的天然橡胶干燥特性之研究

为探讨微波干燥天然橡胶新技术，分别在温度115℃下，采用电热烘箱产生热空气和微波干燥装置干燥湿天然橡胶胶粒，对二者的干燥特性及硫化胶性能进行对比分析研究。结果表明，微波干燥只需13．467min就可使胶料含水量降至0．791％，热空气干燥则需211min。天然橡胶微波干燥和热空气干燥主要包含失水率加速期、失水率减速期、失水率相对恒速期3个失水阶段。整个干燥过程中，微波干燥失水率较大，而热空气干燥失水率比较小。微波干燥天然橡胶硫化胶的耐热氧老化性能得到显著提高：其老化前后拉断伸长率变化率（-35％）和拉伸强度变化率（-59％）明显高于热风干燥天然橡胶硫化胶的拉断伸长率变化率（-62％）和拉伸强度变化率（-89％）。     

Investigation on release of highly water soluble drug from matrix-coated pellets prepared by extrusion–spheronization technique

The objective was to formulate itopride HCl (ITP) extended release matrix-coated pellets by extrusion–spheronization and to investigate the influence of concentration and viscosity grade of different polymers on release of a highly water soluble drug. The matrix pellet formulations consisted of polymers (10–30%) like hydroxypropyl methylcellulose (HPMC K4M, K15M, and K100M), ethyl cellulose (EC-7 cps), microcrystalline cellulose (10–30%) and a fixed quantity of lactose (10%). The initial fast drug release from the matrix pellets was effectively controlled by coating with 5% ethyl cellulose (10 cps) dispersion. The dissolution studies of coated formulations were carried out at different pH, and data were analyzed for drug release kinetics. Scanning electron microscope was used to examine the surface morphology and cross section of pellets. Kinetics of all coated formulations were best explained by Higuchi model (R ² = 0.94–0.99). However, HPMC matrix-coated pellets (F1, F4 and F7) also followed Baker and Lonsdale model (R ² = 0.96–0.99), whereas, EC matrix-coated pellets (F10) followed zero-order kinetics (R ² = 0.99). Release mechanism of all coated formulations was non-fickian. Both uncoated and coated pellets were found to be spherical. Fourier transform infrared spectroscopy was conducted on the coated formulations and no drug–excipients interaction was found.     

Optimization of preparation of matrix pellets containing ethylcellulose

The aim of this study was to investigate the effects of the parameters of the spheronization and the nature of the wetting liquid on the properties of matrix pellets prepared by extrusion and spheronization. Ethylcellulose was used as a matrix former, microcrystalline cellulose as a filler, atenolol as a model active agent, and water and a water–ethanol mixture as liquids. The formation of the pellets and the interactions of the components were evaluated via mechanical, dissolution and morphological studies on the pellets. A factorial design was used to determine the effects of the evaluated factors. It was concluded that significant effects were exerted not only by the operational parameters, but also by the nature of the liquid. The breaking hardness and the dissolution revealed that the ethanol in the liquid caused changes in the wettability of the components and consequently in the matrix structure. This was explained by a comparison of the relative importance of the factors. The alterations induced by ethanol were preferable in the dissolution, because the possibility of the burst effect in the first phase of dissolution can then be avoided. However, it is not favourable as concerns the sphericity and the mechanical properties of the pellets.     

Studies on Hot Air and Microwave Vacuum Drying of Wild Cabbage

Wild cabbage was dehydrated by a combination of hot-air drying and microwave vacuum drying. It showed that the total drying time was reduced by about half while the retention values of the nutrient components and chlorophyll were improved significantly. Microwave/vacuum-dried products had a more porous texture. Finally, microwave drying showed effective bactericidal action in the product with acceptable quality of dried product.     

Dehydration of Garlic Slices by Combined Microwave-Vacuum and Air Drying

Abstract

Combination of microwave-vacuum drying and air drying was investigated as a potential mean for drying garlic slices. The sample was dried by microwave-vacuum until the moisture content reached 10% (wet basis), and then by conventional hot-air drying at the temperature of 45°C to final moisture content less than 5% (wet basis). Pungency, color, texture, and rehydration ratio of garlic slices dried by this method were evaluated and compared with those dried by freeze drying and conventional hot-air drying. The comparison showed that the quality of garlic slices dried by the current method was close to that of freeze dried garlic slices and much better than that of conventional hot-air dried ones. The lab microwave-vacuum dryer which the materials to be dried could be rotated in the cavity was developed by the authors.     

Dehydration of Garlic Slices by Combined Microwave-Vacuum and Air Drying

Combination of microwave-vacuum drying and air drying was investigated as a potential mean for drying garlic slices. The sample was dried by microwave-vacuum until the moisture content reached 10% (wet basis), and then by conventional hot-air drying at the temperature of 45°C to final moisture content less than 5% (wet basis). Pungency, color, texture, and rehydration ratio of garlic slices dried by this method were evaluated and compared with those dried by freeze drying and conventional hot-air drying. The comparison showed that the quality of garlic slices dried by the current method was close to that of freeze dried garlic slices and much better than that of conventional hot-air dried ones. The lab microwave-vacuum dryer which the materials to be dried could be rotated in the cavity was developed by the authors.     

Studies on Hot Air and Microwave Vacuum Drying of Wild Cabbage

Abstract

Wild cabbage was dehydrated by a combination of hot-air drying and microwave vacuum drying. It showed that the total drying time was reduced by about half while the retention values of the nutrient components and chlorophyll were improved significantly. Microwave/vacuum-dried products had a more porous texture. Finally, microwave drying showed effective bactericidal action in the product with acceptable quality of dried product.     

1-脱氧野尻霉素控释微丸的制备工艺优化及其药动学研究

1-脱氧野尻霉素控释微丸采用挤出滚圆和流化床方法进行制备。首先使用羟丙基甲基纤维素和微晶纤维素等辅料制备分散体、丸芯,再使用羟丙基甲基纳米纤维素邻苯二甲酸酯作为主要包衣材料进行包衣,并装入胶囊。采用SEM观察微丸的微观形态,以及测定其产率、脆碎度、密度、水分含量和粒径分布等物理性质,研究结果显示微丸性质符合中国药典标准规定。在体外释药试验中,溶出介质和放置方式对药物释放无显著影响,释放过程符合Baker-Lonsdale模型。对比研究1-脱氧野尻霉素原料药、分散体微丸和控释微丸在比格犬体内的控释特性,结果表明：与1-脱氧野尻霉素原料药相比,分散体微丸和控释微丸分别使1-脱氧野尻霉素的生物利用度提高了183.37%和243.87%。此外,1-脱氧野尻霉素控释微丸的体内-体外研究的相关性分析可知体外溶出和体内吸收之间呈现良好的线性关系。     

Strawberry drying: Development of a closed-cycle modified atmosphere drying system for food products and the performance evaluation of a case study

In the present study, a closed-cycle modified atmosphere drying (CC-MAD) system was developed as an alternative drying technique to facilitate drying processes for agricultural commodities appropriate to highly humid and sunny regions with a better quality. An absorption dehumidifying system was designed for working pseudo-continuously with the most efficient absorbent in terms of moisture absorption, desorption rate, and capacity. The system, assisted by a solar panel for absorbent regeneration, was tested, while its optimum working condition was determined by strawberry drying. This unique process was comparatively carried out using hot-air and freeze-drying techniques in terms of processing time and final product quality. Strawberry slices (5?mm thickness) were dried successfully using CC-MAD. The optimum drying conditions of CC-MAD were determined as drying temperature of 60°C, drying air/gas velocity of 3?m/s and drying medium oxygen level of 9.47%. The loss of ascorbic acid was significantly reduced by CC-MAD technique. These losses were found to be 2.9, 6.9, 27.2, and 23.8% by freeze-drying, CC-MAD, hot-air drying, and hot-air drying combined with CC-MAD, respectively. The total monomeric anthocyanins loss was also significantly reduced by the CC-MAD technique (20.3%), in a similar way to that of freeze-drying (18.1%) in comparison with hot-air drying (40.4%). In addition, CC-MAD (12,446?kJ/kg fresh product at 4?h drying time) is three times more advantageous in terms of energy cost compared with freeze-drying (30492.8?kJ/kg fresh product at 24?h drying time) and six times faster in terms of drying time. This new drying system can be used as an alternative to freeze-drying in the drying of foods, especially in products sensitive to oxidation.     

Effect of Microwave-Vacuum Drying on the Carotenoids Retention of Carrot Slices and Chlorophyll Retention of Chinese Chive Leaves

Microwave-vacuum drying, and combined microwave-vacuum with air or vacuum drying were investigated as potential methods for drying green and high-carotenoid vegetables of Chinese chive leaves and carrot slices. The samples were dried by microwave-vacuum until the moisture content reached about 20% (wet basis), and then by conventional air drying at the temperature of 45-50°C or conventional vacuum drying at the temperature of 55-60°C or by continued microwave-vacuum drying at lower power level to final moisture content about 6% (wet basis). The carotenoid retention of carrot slices and chlorophyll retention of Chinese chive leaves, dried by these methods, was evaluated and compared with those dried by freeze-drying and conventional hot-air drying. The comparison showed that the carotenoid retention of carrot slices and chlorophyll retention of chive leaves, dried by the current methods, was very close to or even as much as those dried by freeze-drying and much better than those dried by conventional hot-air. Blanching was not necessary when using microwave-vacuum drying or combined microwave-vacuum with conventional hot-air drying or vacuum drying, because the activity of enzymes which were responsible for the degradation of color was greatly reduced with extremely rapid decreasing of moisture, and because oxygen was absent in microwave-vacuum drying.     

Effects of drying process for amorphous waxy maize starch on theophylline release from starch‐based tablets

Physical properties and theophylline‐release profiles of compressed tablets prepared with amorphous waxy maize starches dried using different methods were examined. A gelatinized waxy maize starch paste (10% solids in water) was either freeze‐dried or oven‐dried (40 or 105°C) until the moisture content reached to <5%. To form the tablets, the dried amorphous starch powders, either with or without theophylline (3 : 10, w/w), were remoistened to a water content of (17 ± 0.2)%, and compressed into tablets. The drying process applied to the amorphous starch powders affected both the compactness and swelling behavior of the tablets. Although no crystallinity was detected in all the starches tested, X‐ray diffraction patterns indicated that starch chains dried at the lower temperature (40°C) are allowed more time to re‐associate during the drying process than those dried at the higher temperature (105°C). The freeze‐dried starch powders formed tablets characterized by greater compactness and rigidity than was observed in the oven‐dried starch samples. The drug release of the tablets prepared with the starch dried at the higher temperature (105°C) occurred at a much slower rate than that of the tablets made with the starch dried at the lower temperature (40°C). The drug release characteristics of the freeze‐dried starch tablets were nearly identical to those of the tablets prepared with the starch dried at 105°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

EFFECT OF PRETREATMENT AND DRYING ON THE QUALITY OF OYSTER MUSHROOMS (PLEUROTUS OSTREATUS)

Fruiting bodies of oyster mushroom were dried by hot-air drying, vacuum-drying and freeze-drying in order to compare food qualities after drying. Prior to drying, mushrooms were subjected to blanching or dipping in sodium metabisulphite solution (1 or 5 g/L), or dipping in citric acid solution (1 or 5 g/L). Drying of raw mushrooms was taken as a control. Blanching reduced the attractiveness of dry mushrooms; sodium metabisulphite improved it. It has been found that pretreatment and drying method affect the course and rate of drying. Samples subjected to hot-air drying and vacuum-drying were darker than those freeze-dried, which were clearly more attractive. The hot-air and vacuum-dried mushrooms on rehydration were inferior in quality to the freeze-dried samples. Flavor of the freeze-dried mushroom was not significantly different from that of the hot-air dried mushrooms. Food quality of dried mushrooms depends significantly on the type of drier used.     

A Comparison of the Effects of Microwave Versus Conventional Drying on the Mechanical Properties Distribution of Dried Green Porcelains

The effect of fast microwave drying of electroporcelain insulator component was studied by determining the reliability parameter. The Weibull modulus was calculated using the three-point bend strength data of a large number of green samples which were dried using microwave energy. The results were compared with those obtained by conventional drying methods. It was observed that in most cases, microwave-dried components yielded higher Weibull modulus than their conventionally dried counterparts. A high modulus value of >15 was achieved on the microwave-dried samples. The analysis of the result was useful in understanding the fast drying process in ceramics.