Authors:Szabolcs Vigvári, Dávid Sipos, Jenő Solt, Áron Vincze, Béla Kocsis, Zsuzsanna Nemes, Ágnes Kappéter, Zsófia Feiszt, Beáta Kovács, and Zoltán Péterfi
et al. [ 14 ]. In this study, our aim was to evaluate the possibility of the use of lyophilized specimen for FMT.
In this study, participants were recruited from the patients
The lyophilized MIBI kit was dissolved in 1 ml sterile saline or 250mg/ml
ascorbic acid and dispensed into 0.2 ml fractions, which were stored at -20 °C for 12 days. The solution was prepared by using
two different protection methods. In the first method evacuated vials were used for storage of fractionated solution while
in the second method an antioxidant agent, ascorbic acid was employed. The radiochemical impurity of 99mTc-MIBI in the unprotected fractions rises with time. Exclusion of air as well addition of ascorbic acid in fractionated solutions
gave very good results. The labeling efficiency and biodistribution of fractionated solutions was the same as the lyophilized
kit even after 12 days.
Authors:J. Saiter, J. Bayard, N. Delahaye, S. Varnier, and C. Vautier
This work presents the performances of a new apparatus developed for thein-situ observation of a freeze drying (lyophilization) phenomenon. The results obtained on the lyophilization kinetics performed
on a standard mixture (aqueous saturated NaCl solution) are presented.
Instrumental neutron activation analysis (INAA) was used to determine the Br and I concentration in the same ten lyophilized and homogenized human thyroid samples prior and after a 20-year storage at room temperature. It was found that long-term storage had no effect on the iodine content. At the same time, the bromine content was about 2-fold lower (p<0.01). It was assumed that possible losses of other halogens can occur under long-term storage of lyophilized biological materials at room temperature.
Measurements of the masses of incorporated water and of the heats of hydration have been performed at 310 K, under air atmosphere saturated with water vapour, on three differently dehydrated samples of the Saccharomyces boulardii yeast in order to evaluate differences in physicochemical properties related to the following dehydration processes: cryodesiccation (or lyophilization) and thermodesiccation (spray drying and in-fluidized-bed heating).Thermogravimetric (TG) experiments have shown that the lyophilized yeast contains less residual water than heat-treated yeasts and that it incorporates more water and more rapidly. Isothermal water sorption of a spherical yeast cell has been represented by a two-parameter equation able to take account of a maximum of the hydration rate when this is taken as a function of time. On the other hand, isothermal DSC experiments have shown that hydration-heat values are higher for the heat-treated yeasts than for the lyophilized one. The TG and DSC results have been shown to be consistent with the idea that the physicochemical properties of a dehydrated yeast are related to cell-wall behaviour during desiccation.
Authors:J. Carpenter, D. Katayama, L. Liu, W. Chonkaew, and K. Menard
The glass transition of lyophilized materials is normally measured by conventional or temperature modulated differential scanning
calorimetry (TMDSC). However, because of the weakness of these transitions when protein concentrations are high, these techniques
are often unable to detect the glass transition (Tg). High ramp rate DSC, where heating rates of 100 K per min and higher are used, has been shown to be able to detect weak
transitions in a wide range of materials and has been applied to these materials in previous work. Dynamic mechanical analysis
(DMA) is also known to be much more sensitive to the presence of relaxations in materials than other commonly used thermal
techniques. The development of a method to handle powders in the DMA makes it now possible to apply this technique to protein
and protein-excipient mixtures. HRR DSC, TMA and DMA were used to characterize the glass transition of lyophilized materials
and the results correlated. DMA is shown to be a viable alternative to HRR DSC and TMA for lyophilized materials.
Authors:Evaneide Lima, Marisa Crespi, C. Ribeiro, and Sonia de Almeida
Leachate samples from a sanitary landfill of Araraquara city and composting usine of Vila Leopoldina, São Paulo, Brazil were
lyophilized to remove the water content. TG/DTG curves at different heating rates were recorded. The second step of the thermal
decomposition of leachate from the Araraquara landfill (CB1), from the composting usine from Vila Leopoldina (CB2) from the organic phase extracted (FO) and aqueous phase (FA) were all kinetically evaluated using the non-isothermal method.
By Flynn-Wall isoconversional method the following values were obtained: E=234±3.65 kJ mol−1 and logA=29.7±0.58 min−1 for CB1; E=129±1.66 kJ mol−1 and logA=11.8±0.10 min−1 for CB2; E=51.6±1.35 kJ mol−1 and logA=6.09±0.09 min−1 for FO and E=76.91±6.33 kJ mol−1 and logA=8.88±0.7 min−1 for FA with 95% confidence level. Applying the procedures of Málek and Koga, SB kinetic model (Šesták-Berggren) is the most
appropriate to describe the decomposition of CB1, CB2, FO and FA.
Authors:Sheri L. Shamblin, Eva Y. Huang, and G. Zografi
The purpose of this study was to measure the effect of co-lyophilized polymers on the crystallization of amorphous sucrose, and to test for a possible relationship between the ability of an additive to raise theTg of a sucrose-additive mixture, relative to theTg of pure sucrose, and its ability to inhibit crystallization. Differential scanning calorimetry was used to measure the glass transition temperature,Tg, the non-isothermal crystallization temperature,Tc, and the induction time for crystallization,Q, of sucrose in the presence of co-lyophilized Ficoll or poly(vinylpyrrolidone) (PVP). The effect of these polymers on the crystallization of sucrose was significant as demonstrated by a marked increase inTc, and in the induction time (Q) in the presence of relatively small amounts (1–10%) of additive. Surprisingly, small amounts of polymeric additive had no effect on theTg of sucrose, although at higher concentrations, theTg increased proportionally. Thus, it appears that the inhibition of sucrose crystallization by the additition of small amounts of a higher-Tg component cannot be attributed solely to changes in molecular mobility associated with an increase inTg.
Authors:J. Lénárt, T. Szigedi, M. Dernovics, and M. Fodor
Fourier transform near infrared spectroscopy (FT-NIR) has been developed for determining the fat and protein contents of hard, semi-hard and processed cheeses. Multivariate calibration models were carried out by partial least squares (PLS) regression. The diffuse reflection spectra of different type of lyophilized cheeses were measured by FT-NIR analyser in the 800–2500 nm spectral range. The calibration set of 62 samples were validated by leave-oneout cross-validation and by prediction set of 31 samples. The optimal result for fat content (root mean square error of cross-validation (RMSECV)=1.0; R2=99.1%, PLS factor= 6) was obtained when the spectra were preprocessed by first derivation (FD) combined with multiplicative scatter correction (MSC) and smoothing. The optimal result for protein content (RMSECV=1.4, R2=97.2%, PLS factor=6) was observed when the first derivation combined with straight line subtraction (SLS) and smoothing spectral preprocessing method was applied.
Authors:T. Ito, Y. Yoshioka, T. Sonoda, Y. Yoshihashi, E. Yonemochi, and K. Terada
ampoule breakage during the freeze-drying process was prevented by the addition
of sodium chloride to the formulation of lyophilization products of sodium
thiopental. In order to clarify the ampoule breakage prevention mechanism,
the physicochemical behavior of the freeze-drying process was monitored by
simultaneous XRD-DSC measurements and thermal mechanical analysis (TMA). During
the freezing process of formulated solution, the smaller heat of fusion of
crystallized ice with the addition of sodium chloride was observed in comparison
to that without sodium chloride. Although a greater amorphous portion remained,
a higher crystal habit of hexagonal ice was reproducibly observed in the XRD
patterns with the addition of sodium chloride during the freezing process.
In the measurement of TMA, the scattering of the thermal expansion rate of
formulated solution was significantly reduced by the addition of sodium chloride.
These observations indicated that the addition of sodium chloride minimized
the scattering of the thermal expansion rate and might be a cause for the
inhibition of glass ampoule breakage during the freeze-drying process.