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In this study, the fibers of invasive species
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OBJECTIVE: To study the large/small granule number ratio, granule morphology, crystal structure, amylopectin and amylose ratio of five kinds of medicinal starches. METHODS: Five kinds of medicinal starches were separated and characterized by self-assembled gravitational field-flow fractionation (GrFFF) instrument and the proportion of large and small starch granules was calculated according to the results. Optical microscopy and scanning electron microscopy were applied to characterize the morphological property of starch. FT-IR and X-ray diffraction were used to obtain the starch crystalline structure and crystallinity. The contents of amylose and amylopectin were determinate by double wavelength method. RESULTS: The large/small granule number ratios of the five kinds of medicinal starches had obvious difference. The size difference was obvious and the shape was different. The change trends of the order and the amorphous structure of different kinds of starches were the same as that of its relative crystallinity; the higher the amylopectin content, the lower the amylopectin/amylopectin was, the better the crystallinity was. CONCLUSION: GrFFF can be used to characterize and separate large and small starch granules, and the results are in agreement with that of other methods.
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Background: Many buildings in Egypt e.g. museums, mosques and churches, do not possess controlled environments for minimizing the risks of damage of wooden artifacts due to the growth of fungi. Fungal damage usually appears as change in wood color, appearance of stains, and sometimes deformation of wooden surfaces. In this study we focused on the effect that some fungi exert on the properties of wooden artifacts and evaluated the effectiveness of different concentrations of chitosan on their protection against damage by mold fungi. Results: Samples were collected from different monuments and environments, and fungi growing on them were isolated and identified. The isolated Penicillium chrysogenum, Aspergillus flavus and /Aspergillus niger strains were used for the infestation of new pitch pine samples. The results revealed that the lightness of samples infected with any of the tested fungi decreased with increasing incubation times. XRD analysis showed that the crystallinity of incubated samples treated individually with the different concentrations of chitosan was lower than the crystallinity of infected samples. The crystallinity index measured by the first and the second method decreased after the first and second months but increased after the third and fourth months. This may due to the reducing of amorphous part by enzymes or acids produced by fungi in wooden samples. Conclusions: The growth of fungi on the treated wood samples decreased with increasing the concentration of chitosan. Hence, it was demonstrated that chitosan prevented fungal growth, and its use could be recommended for the protection of archeological wooden artifacts.
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Antifungal Agents/pharmacology , Chitosan/chemistry , Fungi/drug effects , Wood/microbiology , Archaeology , Aspergillus flavus/drug effects , Aspergillus flavus/isolation & purification , Aspergillus niger/drug effects , Aspergillus niger/isolation & purification , Chitosan/pharmacology , Crystallization , Penicillium chrysogenum/drug effects , Penicillium chrysogenum/isolation & purification , Spectrophotometry, UltravioletABSTRACT
The study aimed at investigating an inclusion complexation technique to improve solubility and dissolution characteristics of carvedilol by successful complexation with β-cyclodextrin. Inclusion complexes (ICs) of drug and β-cyclodextrin were prepared by kneading method in four different ratios. Physical mixtures were also prepared in identical ratios to compare the efficacy of prepared ICs. The preparations were subjected to rheological studies, drug loading, in vitro release study, FT-IR spectroscopy, thermal events analysis by DSC, X-ray diffraction, scanning electron microscopy (SEM) and accelerated stability study. IC granules were free flowing and compressible. FT-IR study denoted to absence of any chemical interactions between drug and carrier. DSC and X-ray diffraction suggested the presence of crystalline drug in the complexes. Dissolution of ICs revealed significant enhancement of release rate and extent compared to untreated drug. MDT, %DE and T25%, T50% and T80% indicated marked improvement in release rate from complexes. Kinetic modeling suggested that fickian diffusion was the predominant mechanism of drug release from solid complexes. Stability samples showed no significant alterations in DSC and FT-IR studies that referred to the stability of ICs. ICs were compatible, effective and stable over time. Further studies can be planned to investigate their therapeutic efficacy.
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OBJECTIVE: To research and regulate the crystal quality of alanylglutamine for improving their stability and pharmacodynamics as well as vacuum freeze-drying efficiency. METHODS: Scanning electron microscopy (SEM), X-ray powder diffractometer (XRD), differential scanning calorimetry (DSC), and thermogravimetric analyzer (TG) as well as lyophilized experiments were used to investigate the effect of pre-freeze method on crystallinity and uniformity of particle size of alanylglutamine. RESULTS: The result of SEM revealed that the lyophilized alanylglutamine with accelerated pre-freeze method is small-size particle with low crystallinity. Then the lyophilized alanylglutamine with multi-step annealing pre-freeze method become uniformly large particle with high crystallinity. The RESULTS of XRD and DSC indicted that, comparing with the lyophilized alanylglutamine with accelerated pre-freeze method, the lyophilized sample with multi-step annealing pre-freeze method is easier to form the crystal medicine with uniform particle size, less crystal defects, high crystallinity. And the former has lower stability than the later. CONCLUSION: The final lyophilized experiment give us a CONCLUSION that using the multi-step annealing pre-freeze method can improve the freeze-drying efficiency and crystal quality of alanylglutamine, which to achieve the ultimate goal of cost and energy saving.
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OBJECTIVE: Drug properties have important effect on the drug nanosuspenions/nanocrystal production and can determine the final particle size and production efficiency. A number of papers have referred to the optimizations of processes expecting the smaller achievable particle sizes as well as increased production efficiency. Aspects such as stabilizer selection are those most commonly described in the literature. The aims of this study are to systematically investigate the mechanism of nanocrystal formation and identify the physical properties that can affect the particle size reduction process. METHODS: The influence of drug properties such as degree of crystallinity and particle morphology on particle size reduction was systematically investigated by producing hesperetin as a model drug. Processes ie spray-drying, rotavapor, and quench-cooling were applied to modify the physical properties of hesperetin. Both unmodified drugs and modified drugs were used for production of nanosuspension. RESULTS: The nanosuspension with the smallest particle size was obtained from spray-dried hesperetin. CONCLUSION: An improved crystal morphology of modified starting material obtained through spray-drying may lead to a more efficient homogenization process. The drug exists in the nanosuspensions as crystalline, which means recrystallization has occurred as a result of the high pressure homogenization process.
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OBJECTIVE: To investigate effect of crystallinity on in vitro and in vivo release behaviors of spherical self-assembly of Recombinant human interferon-alpha (rhIFN). METHODS: rhIFN can form spherical self-assembly by static crystallization method. The crystallinity was determined by X-ray to characterize molecular ordered degree of various spherical crystals. The drug dissolution in vitro and the pharmacokinetics in vivo of various rhIFN forms were further investigated. RESULTS: The spherical self-assembly of rhIFN in amorphous and crystalline forms were obtained through adjusting protein supersaturation during self-assembly process. The amorphous precipitates were characterized as recovery of 96.5% and mean diameter size of 0.6 μm. Two kinds of crystallized rhIFN were characterized as mono-dispersed spheres, with yield of ≤ 80%, mean diameter size of 10-20 μm. Their crystallinity was 23.2% and 30.8%, respectively. The dissolving rates of spherical self-assemblies were decreased significantly with increased crystallinity. After s.c. administration of spherical self-assembly of rhIFN in amorphous and crystalline forms, the peak time (tmax) were retarded from(6.00±1.40) h to (13.20±2.68) and (22.40±3.57) h, the corresponding half life (t1/2) were prolonged from (4.75±0.82) h to (10.68±1.97) and (29.17±4.93) h. CONCLUSION: The spherical self-assemblies of rhIFN in crystalline form can improve their release performance either in vitro or in vivo, which provide a new candidate for sustained delivery of therapeutic proteins.
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The objective of this study was to develop stable lyophilized product of Bivalirudin, a direct thrombin inhibitor with good reconsti-tution time, % yield of good vials and cake quality. The % loss of crystallinity was determined by DSC for any crystallographic changes of the bulking agent after freeze drying. The glass transition temperature of 5% w/v of Bivalirudin, 3% w/v of mannitol and 0.03% of sodium acetate was approximately -31°C and the collapse temperature was approximately -28°C. Tubular vials were found to withstand the thermal transition during freeze drying. Water content was inversely proportional to the primary drying set point. Reconstitution time was inversely proportional to annealing temperature and vacuum set point. The % yield of good vials and cake quality was directly proportional to annealing time and primary drying set point. The % loss of crystallinity by DSC was independ-ent of all factors and directly proportional to annealing time. Drying at -10°C results in transition of β form of mannitol, whereas drying at -7.5°C and -5°C results in α and δ form of mannitol respectively. On annealing at -7°C for 54 minutes and drying at -6.5°C at 215mT lyophilized product with less than 2% water content, reconstitution time less than 10 seconds, with high yield of more than 95% yield of good vials with best cake quality was obtained.
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The objective of this study was to develop stable lyophilized product of Bivalirudin, a direct thrombin inhibitor with good reconsti-tution time, % yield of good vials and cake quality. The % loss of crystallinity was determined by DSC for any crystallographic changes of the bulking agent after freeze drying. The glass transition temperature of 5% w/v of Bivalirudin, 3% w/v of mannitol and 0.03% of sodium acetate was approximately -31°C and the collapse temperature was approximately -28°C. Tubular vials were found to withstand the thermal transition during freeze drying. Water content was inversely proportional to the primary drying set point. Reconstitution time was inversely proportional to annealing temperature and vacuum set point. The % yield of good vials and cake quality was directly proportional to annealing time and primary drying set point. The % loss of crystallinity by DSC was independ-ent of all factors and directly proportional to annealing time. Drying at -10°C results in transition of β form of mannitol, whereas drying at -7.5°C and -5°C results in α and δ form of mannitol respectively. On annealing at -7°C for 54 minutes and drying at -6.5°C at 215mT lyophilized product with less than 2% water content, reconstitution time less than 10 seconds, with high yield of more than 95% yield of good vials with best cake quality was obtained.
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The starches obtained from two different yam residues, which were treated with alkali(starch-A) or enzyme (starch-E), were studied and compared with yam starch isolated using ordinary method (starch-O) for morphological, crystalline pattern, thermal, and pasting properties. The results revealed that the amylose content of three starches ranged from 19.47 to 22.17 percent. The granule surfaces of starch-A and starch-E were as smooth as that of starch-O. The crystalline pattern of the three starches was a C-type. The transition temperatures (To, Tp and Tc) varied from 70.11 to 73.64, 79.23 to 81.74, and 84.30 to 86.65 ºC, respectively. The starch-E showed the highest Δ Hgel, followed by the starch-A, while it was lowest for the starch-O. According to the viscosity measurement, starch-O had the lowest pasting temperature, highest peak viscosity and breakdown viscosity, which were contrary to those of starch-E.
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El catalizador de FCC está constituido por partículas de composición compleja donde el componente activo es una zeolita Y. En este trabajo se presentan los resultados texturales y estructurales de una zeolita USY comercial lixiviada, de una serie de catalizadores con 7, 15, 25, 35 y 45% de material activo y los de estos materiales desactivados hidrotérmicamente. Las muestras se caracterizaron por fluorescencia de rayos X (FRX), difracción de rayos X (DRX), resonancia magnética nuclear de silicio (29Si RMN) y fisiadsorción de nitrógeno a 77 K. A partir de estos resultados se hallaron correlaciones entre el volumen de microporo y el contenido de zeolita y entre el grado de cristalinidad y el porcentaje de zeolita. Además, se encontró que un tratamiento con sólo 20% de vapor de agua a 1033 K durante 16 horas destruye los grupos estructurales Si(2Al) y Si(3Al) como reflejo de la dealuminización drástica que sufre el material.
FCC catalyst is made up of particles of complex composition where the main active component is a Y zeolite. This work presents the textural and structural results of a commercial USY zeolite which had been previously prepared from a set of catalysts with 7, 15, 25, 35 y 45% of active material and of the hydrothermally deactivated materials zeolite. The samples have been characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), 29Si NMR spectroscopy and nitrogen adsorption at 77K. From these results was found correlations between micropore volume and zeolite content and degree crystallinity and %zeolite. Also, it was found that an hydrothermal treatment at 1033 K with only 20% steam during 16 hours destroys the structural groups Si(2Al) and Si(3Al) as a reflection of the strongly dealumination of the zeolite component of the catalyst.