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1.
The objective of this study was to investigate the properties of granules and tablets with carbamazepine which were prepared
employing a fluidized hot-melt granulation (FHMG) technique. The FHMG process was carried out at 65°C. Macrogol 6000 (PEG
6000) was used as a binder at the content 10% (w/w) of the granulated mass. Granules containing up to 70% (w/w) of the drug and 20–90% (w/w) of a filler (lactose, mannitol, calcium hydrogen phosphate (Di-Cafos), pregelatinized starch, and microcrystalline cellulose
(MCC)) were produced. When the drug content was 30% (w/w), the yield of the process was satisfying (>95%) and flowability of the granules was better than placebo granules or drug-loaded
granules prepared by wet granulation. Type of a filler had strong impact on physical properties of granules, and size distribution
of the particles was the most homogenous when lactose or Di-Cafos were used. The FHMG technique enabled preparation of granules
with better compressability compared with the wet-granulated product or with non-granulated powders. Tablets with shorter
disintegration time than 10 min were obtained with 2.0% crospovidone added as a disintegrant. In comparison to tablets prepared
from the wet-granulated mass, employment of the FHMG method resulted in tablets with faster dissolution of carbamazepine (more
than 80% of the drug released within 15 min). This was achieved with mannitol or lactose/MCC, as fillers. 相似文献
2.
This study investigated the influence of excipient composition to the roller compaction and granulation characteristics of
pharmaceutical formulations that were comprised of a spray-dried filler (lactose monohydrate or mannitol), pregelatinized
starch, talc, magnesium stearate (1% w/w) and a ductile active pharmaceutical ingredient (25% w/w) using a mixed-level factorial design. The main and interaction effects of formulation variables (i.e., filler type, starch
content, and talc content) to the response factors (i.e., solid fraction and tensile strength of ribbons, particle size, compressibility
and flow of granules) were analyzed using multi-linear stepwise regression analysis. Experimental results indicated that roller
compacted ribbons of both lactose and mannitol formulations had similar tensile strength. However, resulting lactose-based
granules were finer than the mannitol-based granules because of the brittleness of lactose compared to mannitol. Due to the
poor compressiblility of starch, increasing starch content in the formulation from 0% to 20% w/w led to reduction in ribbon solid fraction by 10%, ribbon tensile strength by 60%, and granule size by 30%. Granules containing
lactose or more starch showed less cohesive flow than granules containing mannitol and less starch. Increasing talc content
from 0% to 5% w/w had little effect to most physical properties of ribbons and granules while the flow of mannitol-based granules was found
improved. Finally, it was observed that stored at 40 °C/75% RH over 12 weeks, gelatin capsules containing lactose-based granules
had reduced dissolution rates due to pellicle formation inside capsule shells, while capsules containing mannitol-based granules
remained immediate dissolution without noticeable pellicle formation. 相似文献
3.
Airaksinen S Karjalainen M Kivikero N Westermarck S Shevchenko A Rantanen J Yliruusi J 《AAPS PharmSciTech》2005,6(2):E311-E322
Phase transformations in formulations can lead to instability in physicochemical, biopharmaceutical, and processing properties
of products. The influences of formulation design on the optimal dosage forms should be specified. The aim here was to investigate
whether excipients with different water sorption behavior affect hydrate formation of nitrofurantoin in wet masses. Nitrofurantoin
anhydrate was used as a hydrate-forming model drug, and 4 excipients with different water-absorbing potential (amorphous low-substituted
hydroxypropylcellulose, modified maize starch, partially amorphous silicified microcrystalline cellulose, and crystalline
α-lactose monohydrate) were granulated with varying amounts of purified water. Off-line evaluation of wet masses containing
nitrofurantoin anhydrate and excipient (1∶1) was performed using an X-ray powder diffractometer (XRPD) and near-infrared spectroscopy,
and drying phase was evaluated by variable temperature XRPD. Only amorphous excipient in the formulation retarded hydrate
formation of an active pharmaceutical ingredient (API) at high water contents. Hygroscopic partially crystalline excipient
hindered hydrate formation of API at low water contents. Crystalline excipient was unable to control hydrate formation of
API. The character of excipient affects the stability of formulation. Thus, correct selection of excipients for the formulation
can control processing-induced phase transitions and improve the storage stability of the final dosage form.
Published: October 6, 2005 相似文献
4.
The aim of this study was to assess the diagnostic properties of the two selective plating media and a chromogenic medium
for identification of Bacillus cereus. The 324 isolates were B. cereus (37%), Bacillus weihenstephanensis (45%) or Bacillus thuringiensis (18%), as identified by a new combination of techniques. All isolates were growing on mannitol–egg yolk–polymyxin agar (MYP),
and they did not form acid from mannitol. However, a significant lower number of B. thuringiensis isolates did not show lecithinase activity. All isolates were also growing on polymyxin–egg yolk–mannitol–bromothymol blue
agar (PEMBA); however, 11% isolates indicated that they did produce acid from mannitol, and 15% isolates did not show any
lecithinase activity. Five of the isolates did not grow at all on the chromogenic agar, and 14 of the growing isolates were
β-glucosidase negative. It is concluded that the two recommended selective plating media MYP and PEMBA for detection of B. cereus group bacteria both have their limitations for identification of some B. cereus, B. weihenstephanensis or B. thuringiensis. However, MYP is preferable compared to PEMBA. The chromogenic medium has its own advantages and limitations, and some of
the limitations seem to be solved by incubation at 30°C instead of the recommended 37°C. 相似文献
5.
Ju Hee Kuk Woo Jin Jung Gyung Hyun Jo Kil Yong Kim Ro Dong Park 《World journal of microbiology & biotechnology》2006,22(2):135-139
Summary
N,N′-diacetylchitobiose was produced from chitin as a major hydrolytic product by controlling the ratio of β-N-acetylglucosaminidase to N,N′-diacetylchitobiohydrolase activities in the crude enzyme preparation of Aeromonas sp. GJ-18. When the enzyme preparation was preincubated at 50 °C, β-N-acetylglucosaminidase was nearly inactivated, while the N,N′-diacetylchitobiohydrolase was still active. Thus, the composition of chitin oligosaccharides depended on the preincubation temperature of the crude enzyme preparations. Typically, after 7 days of incubation with the substrate chitin, 78.9 and 56.6% of N,N′-diacetylchitobiose yields were obtained from swollen α-chitin and powdered β-chitin, respectively, with enzyme preparations that had been pretreated at 50 °C for 60 min. 相似文献
6.
Bacillus thuringiensis is an insecticidal bacterium whose chitinolytic system may be exploited to improve the insecticidal system of Bt-crops. A
nucleotide fragment of 1368 bp from B. thuringiensis serovar konkukian S4, containing the complete coding sequence of the chitin binding protein Cbp50, was cloned and sequenced. Analyses have shown the protein to contain a modular structure consisting of an N-terminal CBM33 domain, two copies of a
fibronectin-like domain and a C-terminal chitin binding domain classified as CBM5. The Cbp50 protein was heterologously expressed
in Escherichia coli, purified and assessed for chitin binding activity. A deletion mutant (CBD-N; containing only the N-terminal CBM33 domain)
of Cbp50 was produced to determine the role of C-terminal domains in the binding activity of the protein. The full-length
Cbp50 was shown to bind β-chitin most efficiently followed by α-chitin, colloidal chitin and cellulose. The polysaccharide
binding activity of CBD-N was drastically decreased. The data demonstrate that both the N-terminal and C-terminal domains
of Cbp50 are essential for the efficient binding of chitin. The purified Cbp50 showed antifungal activity against the phytopathogenic
fungus Fusarium oxysporum and the opportunistic human pathogen Aspergillus niger. This is the first report of a modular chitin binding protein in bacteria. 相似文献
7.
Fu S Thacker A Sperger DM Boni RL Velankar S Munson EJ Block LH 《AAPS PharmSciTech》2010,11(4):1662-1674
Polymeric excipients are often the least well-characterized components of pharmaceutical formulations. The aim of this study
was to facilitate the QbD approach to pharmaceutical manufacturing by evaluating the inter-grade and inter-batch variability
of pharmaceutical-grade polymeric excipients. Sodium alginate, a widely used polymeric excipient, was selected for evaluation
using appropriate rheological methods and test conditions. The materials used were six different grades of sodium alginate
and an additional ten batches of one of the grades. To compare the six grades, steady shear measurements were conducted on
solutions at 1%, 2%, and 3% w/w, consistent with their use as thickening agents. Small-amplitude oscillation (SAO) measurements were conducted on sodium
alginate solutions at higher concentrations (4–12% w/w) corresponding to their use in controlled-release matrices. In order to compare the ten batches of one grade, steady shear
and SAO measurements were performed on their solutions at 2% w/w and 8% w/w, respectively. Results show that the potential interchangeability of these different grades used as thickening agents could
be established by comparing the apparent viscosities of their solutions as a function of both alginate concentration and shear
conditions. For sodium alginate used in controlled-release formulations, both steady shear behavior of solutions at low concentrations
and viscoelastic properties at higher concentrations should be considered. Furthermore, among batches of the same grade, significant
differences in rheological properties were observed, especially at higher solution concentrations. In conclusion, inter-grade
and inter-batch variability of sodium alginate can be determined using steady shear and small-amplitude oscillation methods. 相似文献
8.
Structure of beta-chitin or parallel chain systems of poly-beta-(1-4)-N-acetyl-D-glucosamine 总被引:2,自引:0,他引:2
J Blackwell 《Biopolymers》1969,7(3):281-298
The structure of β-chitin has been reexamined in an X -ray diffraction study of the highly crystalline material available from pogonophore tubes. Oriented specimens were prepared by suspending the dispersed deproteinized tube in a fibrin clot which was then stretched into an oriented fiber. The X -ray diffraction patterns of pogonophore β-chitin were explained by proposing that this material consists of a mixture of two structural phases which have been named β-chitins A and B. This view was confirmed by the preparation of specimens which gave only the diffraction pattern of the A phase by treating the tubes with diaphanol. Both A and B phases gave rise to a series of hydrate structures. The lowest hydrate of β-chitin A has been studied in detail and shown to consist of an anhydrous system of parallel chitin chains. For this form, the unit cell was monoclinic with dimensions a = 4.85 Å, b = 10.38 Å (fiber axis), c = 9.26 Å, and β = 97.5°, and space group P21. Reasonable agreement was obtained between the observed X -ray intensities and those calculated for such a structure. Examination of the β-chitin of Loligo pen and diatom spines showed that these materials also consist of these A and B phases. 相似文献
9.
R. Jayakumar V.V. Divya Rani K.T. Shalumon P.T. Sudheesh Kumar S.V. Nair T. Furuike H. Tamura 《International journal of biological macromolecules》2009,45(3):260-264
Chitin is a novel biopolymer and has excellent biological properties such as biodegradation in the human body and biocompatible, bioabsorable, antibacterial and wound healing activities. In this work, α- and β-chitin membranes were prepared using α- and β-chitin hydrogel. The bioactivity studies were carried out using these chitin membranes with the simulated body fluid solution (SBF) for 7, 14 and 21 days. After 7, 14 and 21 days the membranes were characterized using SEM, EDS and FT-IR. The SEM, EDS and FT-IR studies confirmed the formation of calcium phosphate layer on the surface of the both chitin membranes. These results indicate that the prepared chitin membranes were bioactive. Cell adhesion studies were also carried out using MG-63 osteoblast-like cells. The cells were adhered and spread over the membrane after 24 h of incubation. These results indicated that the chitin membranes could be used for tissue-engineering applications. 相似文献
10.
Viviana García Mir Jyrki Heinämäki Osmo Antikainen Niklas Sandler Ofelia Bilbao Revoredo Antonio Iraizoz Colarte Olga Maria Nieto Jouko Yliruusi 《AAPS PharmSciTech》2010,11(1):409-415
A “simplex-centroid mixture design” was used to study the direct-compression properties of binary and ternary mixtures of chitin and two cellulosic direct-compression diluents. Native milled and fractioned (125–250 μm) crustacean chitin of lobster origin was blended with microcrystalline cellulose, MCC (Avicel® PH 102) and spray-dried lactose–cellulose, SDLC Cellactose® (composed of a spray-dried mixture of alpha-lactose monohydrate 75% and cellulose powder 25%). An instrumented single-punch tablet machine was used for tablet compactions. The flowability of the powder mixtures composed of a high percentage of chitin and SDLC was clearly improved. The fractioned pure chitin powder was easily compressed into tablets by using a magnesium stearate level of 0.1% (w/w) but, as the die lubricant level was 0.5% (w/w), the tablet strength collapsed dramatically. The tablets compressed from the binary mixtures of MCC and SDLC exhibited elevated mechanical strengths (>100 N) independent of the die lubricant level applied. In conclusion, fractioned chitin of crustacean origin can be used as an abundant direct-compression co-diluent with the established cellulosic excipients to modify the mechanical strength and, consequently, the disintegration of the tablets. Chitin of crustacean origin, however, is a lubrication-sensitive material, and this should be taken into account in formulating direct-compression tablets of it. 相似文献
11.
A chitinase (VpChiA) and its C-terminal truncated G589 mutant (VpChiAG589) of Vibrio parahaemolyticus were cloned by polymerase chain reaction (PCR) techniques. To study the role of the C-terminal 30 amino acids of VpChiA in
the enzymatic hydrolysis of chitin, both the recombinant VpChiA and VpChiAG589 encoded in 1,881 and 1,791 bp DNA fragments,
respectively, were expressed in Escherichia coli using the pET-20b(+) expression system. The His–Tag affinity purified VpChiA and VpChiAG589 enzymes had a calculated molecular
mass of 65,713 and 62,723 Da, respectively. The results of biochemical characterization including kinetic parameters, spectroscopy
of fluorescence and circular dichroism, chitin-binding and hydrolysis, and thermostability, both VpChiA and VpChiAG589, had
very similar physicochemical properties such as the optimum pH (6), temperature (40°C), and kinetic parameters of Km and kcat against the 4MU–(GlcNAc)2 or 4MU–(GlcNAc)3 soluble substrates. The significant increase of thermostability and the drastic decrease of the hydrolyzing ability of VpChiAG589
toward the insoluble α-chitin substrate suggested that a new role could be played by the C-terminal 30 amino acids. 相似文献
12.
《Bioscience, biotechnology, and biochemistry》2013,77(5):968-969
For identification of how explosion increases the reactivity of chitin and chitosan, changes in the crystalline polymorphism of these polysaccharides were studied by X-ray diffraction measurements. The α-chitin form of chitin did not change after being exploded, but an X-ray diagram of chitosan showed a hydrated crystal of low crystallinity before the explosion, and increased crystallinity of the hydrated form plus a small amount of an anhydrous crystal after the explosion. The improvement of accessibility to both polysaccharides caused by the explosion seemed not to arise from changes in their crystalline polymorphism or crystallinity 相似文献
13.
Fu-Pang Lin Hsu-Han Chuang Yi-Hsuan Liu Chia-Yu Hsieh Pei-Wen Lin Hsu-Yang Lin 《Archives of microbiology》2009,191(3):265-273
C-Terminal truncation mutagenesis was used to explore the functional and structural significance of the C-terminal region
of Aeromonas caviae D1 chitinase (AcD1ChiA). Comparative studies between the engineered full-length AcD1ChiA and the truncated mutant (AcD1ChiAK606)
included initial rate kinetics, fluorescence and circular dichroism (CD) spectrometric properties, and substrate binding and
hydrolysis abilities. The overall catalytic efficiency, k
cat/K
M, of AcD1ChiAK606 with the 4MU-(GlcNAc)2 and the 4MU-(GlcNAc)3 chitin substrates was 15–26% decreased. When compared with AcD1ChiA, the truncated mutant AcD1ChiAK606 maintained 80% relative
substrate-binding ability and about 76% of the hydrolyzing efficiency against the insoluble α-chitin substrate. Both fluorescence
and CD spectroscopy indicated that AcD1ChiAK606 retained the same conformation as AcD1ChiA. These results indicated that removal
of the C-terminal 259 amino acid residues, including the putative chitin-binding motif and the A region (a motif of unknown
function) of AcD1ChiA, did not seriously affect the enzyme structure integrity as well as activity. The present study provided
evidences illustrating that the binding and hydrolyzing of insoluble chitin substrates by AcD1ChiA were not absolutely dependent
on the putative C-terminal chitin-binding domain and the function-unknown A region. 相似文献
14.
15.
The purpose of this study was to improve dissolution behavior of poorly water-soluble drugs by application of cyclodextrin
in extrusion processes, which were melt extrusion process and wet extrusion process. Indomethacin (IM) was employed as a model
drug. Extrudates containing IM and 2-hydroxypropyl-β-cyclodextrin (HP-β-CyD) in 1:1 w/w ratio were manufactured by both melt extrusion process and wet extrusion process. In vitro drug release properties of IM from extrudates and physiochemical properties of extrudates were investigated. The dissolution
rates of IM from extrudates manufactured by melt extrusion and wet extrusion with HP-β-CyD were significantly higher than
that of the physical mixture of IM and HP-β-CyD. In extrudate manufactured by melt extrusion, γ-form of IM changed to amorphous
completely during melt extrusion due to heating above melting point of IM. On the other hand, in extrudate manufactured by
wet extrusion, γ-form of IM changed to amorphous partially due to interaction between IM and HP-β-CyD and mechanical agitating
force during process. Application of HP-β-CyD in extrusion process is useful for the enhancement of dissolution rate for poorly
water-soluble drugs. 相似文献
16.
Epicoccum nigrum conidia were produced by solid fermentation on wheat grains (cv. Rendeveaux and Brigadier) at different water activities
(aw). Conidial production was highest at high aw(0.996) than at reduced aw (0.98). However, conidial production at reduced aw was improved when the aw of the substrate was adjusted with a mixture of glycerol and water. Maximum levels ofconidiation were 7–11 × 106 conidia g−1 grain. The aw of the solid substrate affected the pattern of accumulation of compatible solutes in the conidia. Mannitol was the main polyol
in all conidialtypes. However, the amounts of mannitol were higher in conidia produced at high aw. At reduced aw the conidia of E. nigrum accumulated moreglycerol, which is more efficient in the osmorregulation proccess than mannitol. Arabitol accumulated in
low amounts, specifically in conidia produced at the lower aw, on cv. Rendeveaux but not on cv. Brigadier. Trehalose was detected in higher amounts in cv. Rendeveaux than in cv. Brigadier,
andthe amounts were higher in conidia produced at high aw. A significant amount of endogenous solutes was detected in the washing liquid used for the separation of the conidia.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
17.
Sabiruddin Mirza Inna Miroshnyk Jyrki Heinämäki Osmo Antikainen Jukka Rantanen Pia Vuorela Heikki Vuorela Jouko Yliruusi 《AAPS PharmSciTech》2009,10(1):113-119
Crystal morphology engineering of a macrolide antibiotic, erythromycin A dihydrate, was investigated as a tool for tailoring
tabletting performance of pharmaceutical solids. Crystal habit modification was induced by using a common pharmaceutical excipient,
hydroxypropyl cellulose, as an additive during crystallization from solution. Observed morphology of the crystals was compared
with the predicted Bravais–Friedel–Donnay–Harker morphology. An analysis of the molecular arrangements along the three dominant
crystal faces [(002), (011), and (101)] was carried out using molecular simulation and thus the nature of the host–additive
interactions was deduced. The crystals with modified habit showed improved compaction properties as compared with those of
unmodified crystals. Overall, the results of this study proved that crystal morphology engineering is a valuable tool for
enhancing tabletting properties of active pharmaceutical ingredients and thus of utmost practical value. 相似文献
18.
Fan Y Fukuzumi H Saito T Isogai A 《International journal of biological macromolecules》2012,50(1):69-76
Water dispersions of TEMPO-oxidized α-chitin nanowhisker (TOChN), partially deacetylated α-chitin nanowhisker/nanofiber mixture (DEChN), HCl-hydrolyzed chitin nanowhisker (HHChN) and squid-pen β-chitin nanofiber (SQChN) were prepared, and the properties of nano-dispersions and their cast films were characterized between the four chitin nano-samples. Because SQChN has the highest aspect ratio, its 0.1% dispersion had the highest shear stress and viscosity at the same shear rate in the four chitin nano-samples, and showed gel-like behavior in the whole shear rate range from 10−3 to 103 s−1. AFM images of the self-standing films showed that film surfaces consisted of characteristic chitin nano-elements with different morphologies and degrees of orientation between the four chitin samples, whereas all chitin nanowhisker/nanofiber films had similar thermal degradation points at ∼200 °C. The DEChN film had the highest tensile strength of ∼140 MPa, elongation at break of ∼10% and light-transmittance of 87% at 400 nm. In contrast, the SQChN film had the lowest tensile strength, Young's modulus and light-transmittance. All chitin nanowhisker/nanofiber films had similar oxygen permeabilities of ∼1 mL μm m−2 day−1 kPa−1, which was clearly lower than that (184 mL μm m−2 day−1 kPa−1) of a poly(lactic acid) film. 相似文献
19.
V. Prakash 《Journal of biosciences》1985,9(3-4):165-175
The protein α-globulin fromSesamum indicum L. has been characterised for its size and shape using αarious chemical, physico-chemical and hydrodynamic properties. The
protein has an S20,w
0 of 12.8, D20,w °f 4.9 × 10-7 cm2/sec and a partial specific αolume of 0.725 ml/g in the natiαe state. The intrinsic αiscosity of the protein was determined
to be 3 0 ml/g indicating it to be globular in shape. The molecular weight of the protein as determined by αarious approaches
in analytical ultracentrifugation αaries from 2.6–2.74 × 105. The molecular weight from sedimentation equilibrium yields a αalue of 2.74 × 105 in the natiαe state and a αalue of 19000 in the dissociated and denatured state in 6 M guanidine hydrochloride. The eαaluation
of frictional ratios using Stokes radius and results from electron microscopy confirms the protein to be globular in shape.
The protein consists of at least 12–14 subunits. The eαaluation of hydrophobic parameters and energetics of interaction of
subunits indicate that the protein is stabilized predominantly by hydrophobic interactions. 相似文献
20.
Marco Cespi Giulia Bonacucina Giovanna Mencarelli Gianfabio Giorgioni Giovanni Filippo Palmieri 《AAPS PharmSciTech》2010,11(3):1232-1236
An innovative and simple methodology has been developed and used for the evaluation of mucoadhesive properties of several
polymers by means of sound speed measurements using high-resolution acoustic spectroscopy. In systems made of polymers in
water, variations in hydration shell of polymeric chains determine changes of dispersions compressibility, and this phenomenon
can be monitored by sound speed measurements. Four different polymers have been selected, namely PEG 6000, Carbopol 974, HPMC
K4M, and Pectin 200/USP, all characterised by very different mucoadhesive properties. Samples made of each polymer alone (0.3–1.0%
w/w) or in mixture with mucin (mucin fixed at 1.0% w/w) in water were investigated while using high-resolution ultrasonic spectrometer at two different frequencies (5.2 and 8.2 MHz).
Polymer–mucin interaction was evaluated comparing experimental sound speed values of polymer–mucin samples with their theoretical
values derived from the addition of sound speeds obtained while analysing each component alone. Results demonstrated the ability
of the acoustic method to discriminate between mucoadhesive and no mucoadhesive polymer–mucin dispersions and allowed also
the comparison between their mucoadhesive strengths. The study has therefore demonstrated the potential of using high-resolution
ultrasonic spectroscopy to evaluate the polymers’ mucoadhesiveness, with the great advantage of testing small amount of samples
even if opaque. 相似文献