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  • 1
    Electronic Resource
    Electronic Resource
    An infrared spectroscopic study of the interactions of carbohydrates with dried proteins (1989)
    s.l. : American Chemical Society
    Biochemistry 28 (1989), S. 3916-3922 
    Details
    ISSN: 1520-4995
    Source: ACS Legacy Archives
    Topics: Biology , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/bi00435a044
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  • 2
    Electronic Resource
    Electronic Resource
    THE ROLE OF VITRIFICATION IN ANHYDROBIOSIS (1998)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Physiology 60 (1998), S. 73-103 
    Details
    ISSN: 0066-4278
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Medicine , Biology
    Notes: Abstract Numerous organisms are capable of surviving more or less complete dehydration. A common feature in their biochemistry is that they accumulate large amounts of disaccharides, the most common of which are sucrose and trehalose. Over the past 20 years, we have provided evidence that these sugars stabilize membranes and proteins in the dry state, most likely by hydrogen bonding to polar residues in the dry macromolecular assemblages. This direct interaction results in maintenance of dry proteins and membranes in a physical state similar to that seen in the presence of excess water. An alternative viewpoint has been proposed, based on the fact that both sucrose and trehalose form glasses in the dry state. It has been suggested that glass formation (vitrification) is in itself sufficient to stabilize dry biomaterials. In this review we present evidence that, although vitrification is indeed required, it is not in itself sufficient. Instead, both direct interaction and vitrification are required. Special properties have often been claimed for trehalose in this regard. In fact, trehalose has been shown by many workers to be remarkably (and sometimes uniquely) effective in stabilizing dry or frozen biomolecules, cells, and tissues. Others have not observed any such special properties. We review evidence here showing that trehalose has a remarkably high glass-transition temperature (Tg). It is not anomalous in this regard because it lies at the end of a continuum of sugars with increasing Tg. However, it is unusual in that addition of small amounts of water does not depress Tg, as in other sugars. Instead, a dihydrate crystal of trehalose forms, thereby shielding the remaining glassy trehalose from effects of the added water. Thus under less than ideal conditions such as high humidity and temperature, trehalose does indeed have special properties, which may explain the stability and longevity of anhydrobiotes that contain it. Further, it makes this sugar useful in stabilization of biomolecules of use in human welfare.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.physiol.60.1.73
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  • 3
    Electronic Resource
    Electronic Resource
    The Role of Platelets in Chilling-Induced Injury (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 714 (1994), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1994.tb12055.x
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  • 4
    Electronic Resource
    Electronic Resource
    Real-Time in Situ Monitoring of Lysozyme During Lyophilization Using Infrared Spectroscopy: Dehydration Stress in the Presence of Sucrose (1997)
    Springer
    Pharmaceutical research 14 (1997), S. 1548-1555 
    Details
    ISSN: 1573-904X
    Keywords: FTIR spectroscopy ; attenuated total reflectance ; internal reflection ; lyophilization ; lysozyme ; sucrose
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. First, to investigate the role of sucrose in stabilizing protein structure (as measured by changes in the amide I band of lysozyme) caused by dehydration encountered during lyophilization. Second, to demonstrate the utility of internal reflection spectroscopy as a tool for conducting controlled lyophilization experiments. Methods. A custom-built internal reflection FTIR accessory was used to follow the entire freeze-drying process of solutions consisting of 49.4 mg/mL lysozyme in the presence and absence of 10% sucrose in real-time. Studies were carried out using D2O as a transparent medium in the infrared region of the protein amide bands. Potential self-association of the protein in the presence of sucrose was investigated using dynamic light scattering. Hydration levels were determined using a multiple regression equation. Differential scanning calorimetry (DSC) permitted characterization of the final lyophilized product. Moisture content was determined using Karl Fischer titration. Results. Throughout freezing and drying, minimal changes were observed both in frequency (1647 ± 1 cm−1) and bandwidth (46 ± 1 cm−l) of the amide I band in the presence of sucrose. In contrast, greater changes in frequency and band width were seen in the absence of sucrose. A successfully lyophilized cake was obtained which had properties of a glass as measured by DSC, with a Tg of 50°C. The lyophilized product containing sucrose had 4% moisture by weight. Three distinct rates of water desorption were discovered during drying under vacuum (50 mg/hr within the sample temperature range from −35° to −25°C; 30 mg/hr from 10° to 25°C; 1.2 mg/hr from 27° to 38°C). Conclusions. The inclusion of sucrose served to minimize perturbations of protein structure caused by freezing and dehydration stresses encountered during lyophilization (compared to studies conducted in the absence of sucrose). The results support the water replacement hypothesis and underscore the role of the sugar in preserving a native structure in the dried state. This investigation demonstrates the usefulness of infrared spectroscopy in evaluating lyophilization process parameters and formulation design.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1012170116311
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  • 5
    Electronic Resource
    Electronic Resource
    Rational Design of Stable Lyophilized Protein Formulations: Some Practical Advice (1997)
    Springer
    Pharmaceutical research 14 (1997), S. 969-975 
    Details
    ISSN: 1573-904X
    Keywords: protein drugs ; design of formulations ; lyophilization ; stabilization of proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1012180707283
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  • 6
    Electronic Resource
    Electronic Resource
    Development of a Stable Freeze-dried Formulation of Recombinant Human Interleukin-1 Receptor Antagonist (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 243-249 
    Details
    ISSN: 1573-904X
    Keywords: freeze-dried formulation ; rhIL-lra ; protein stability
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. A formulation of recombinant human interleukin-1 receptor antagonist (rhIL-1ra) was developed that provided both acute protection during lyophilization and storage stability in the dried solid. Methods. The formulation was optimized by monitoring the impact of excipients on protein degradation which was analyzed by turbidimetry and cation-exchange HPLC. Results. The most appropriate pH was 6.5. Sodium citrate buffer provided better stability than sodium phosphate buffer. Glycine was selected as a bulking agent because the greatest protein stability was noted when this bulking agent was used in combination with an amorphous protein stabilizer. Among the amorphous stabilizers tested, sucrose protected rhIL-lra best in the presence of glycine. When the protein was freeze-dried in the presence of an inadequate mass ratio of sucrose/protein (〈 0.3), the rate of degradation of rhIL-lra increased. For a formulation containing 100 mg/ml of rhIL-lra, increasing the sucrose/protein mass ratio to ≥ 0.3 greatly increased storage stability. The moisture content of the dried solid affected the storage stability to a minor degree. Three different stoppers obtained from the WEST Company did not affect the stability of rhIL-lra. Conclusions. An optimized formulation could be reconstituted without precipitation after 14 months at 30 or 50°C. At 30°C, there was no loss of native protein due to deamidation, and only a 4% loss at 50°C. These results indicated that the optimized formulation could be stored at ambient temperatures for long periods, without damage to the protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016043114998
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  • 7
    Electronic Resource
    Electronic Resource
    Thermal Stability of Low Molecular Weight Urokinase During Heat Treatment. II. Effect of Polymeric Additives (1994)
    Springer
    Pharmaceutical research 11 (1994), S. 1004-1008 
    Details
    ISSN: 1573-904X
    Keywords: protein stability ; aggregation ; turbidimetry ; urokinase ; formulation ; additives, polymeric
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Turbidimetric or light scattering assays can be used to determine the extent of aggregation in protein formulations. Using low molecular weight urokinase (LMW-UK) as a model protein, the effect of polymeric additives on heat-induced aggregation was evaluated. Previous work has shown that under 60°C heat treatment, LMW-UK initially denatures and the unfolded protein associates to form soluble aggregates. Eventually, these aggregates associate to form a precipitate. The effects of polymers on the initial aggregation phase was examined. Hydroxyethyl (heta) starch, polyethylene glycol 4000, and gelatin were found to be effective, concentration-dependent inhibitors of aggregation, whereas polyvinylpyrrolidone (PVP) and polyethylene glycol 300 were ineffective. Overall, the effect of polymeric additives on the stability of thermally-stressed LMW-UK can be accounted for by preferential exclusion of the solute from the surface of the protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018935420680
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of Sugars and Polymers on Crystallization of Poly(ethylene glycol) in Frozen Solutions: Phase Separation Between Incompatible Polymers (1996)
    Springer
    Pharmaceutical research 13 (1996), S. 1393-1400 
    Details
    ISSN: 1573-904X
    Keywords: frozen solution ; phase separation ; poly(ethylene glycol) ; crystallization ; molecular interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. This study examined the effect of third components (low-molecular-weight saccharides and polymers) on the crystallization of poly(ethylene) glycol (PEG) in frozen solutions, focusing on the relationship between their crystallization-inhibiting ability and molecular compatibility. Methods. Effects of sugars and polymers on the crystallization of PEG 3000 in frozen solution were monitored by differential scanning calorimetry (DSC). Pulsed-NMR was employed to monitor the molecular mobility of water and solutes in the frozen solutions. Miscibility between PEG and third components in aqueous solution was estimated from the lowering of cloud point of PEG 20,000. Thermal analysis of frozen solutions containing some non-crystallizing solutes was used to examine the possibility of phase separation in frozen solutions. Results. Some sugars and polymers inhibited the crystallization of PEG and formed practically stable amorphous phases among ice crystals. The mobility of solute molecules in the amorphous phase increased above the softening temperature of maximally concentrated solutions (Ts), whereas that of water molecules appeared at a lower temperature. Mono- and disaccharides that are relatively less miscible with PEG in solution inhibit PEG crystallization to a lesser degree. Two Ts regions were observed in frozen solutions containing both polyvinylpyrrolidone (PVP) and dextran, at much lower concentrations than those causing aqueous two-phase separation at ambient temperatures. Conclusions. Ice crystallization raises the concentration of solutes in the remaining solution, which can lead to phase separation in the amorphous phase. Molecular compatibility between components is an important factor determining their propensity to phase separate and crystallize.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1016086319851
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  • 9
    Electronic Resource
    Electronic Resource
    Approaches for increasing the solution stability of proteins (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 506-512 
    Details
    ISSN: 0006-3592
    Keywords: protein stabilization ; urokinase ; denaturation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Stabilization of proteins through proper formulation is an important challenge for the pharmaceutical industry. Two approaches for stabilization of proteins in solution are discussed. First, work describing the effect of additives on the thermally induced denaturation and aggregation of low molecular weight urokinase is presented. The effects of these additives can be explained by preferential exclusion of the solute from the protein, leading to increased thermal stability with respect to denaturation. Diminished denaturation leads to reduced levels of aggregation. The second approach involves stoichiometric replacement of polar counter ions (e.g., chloride, acetate, etc.) with anionic detergents, in a process termed hydrophobic ion pairing (HIP). The HIP complexes of proteins have increased solubility in organic solvents. In these organic solvents, where the water content is limited, the thermal denautration temperatures greatly exceed those observed in aqueous solution. In addition, it is possible to use HIP to selectively precipitate basic proteins from formulations that contain large amounts of stabilizers, such as human serum albumin (HSA), with a selectivity greater than 2000-fold. This has been demonstrated for various mixtures of HSA and interleukin-4. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260480513
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  • 10
    Electronic Resource
    Electronic Resource
    Protein–Solvent Interactions in Pharmaceutical Formulations (1991)
    Springer
    Pharmaceutical research 8 (1991), S. 285-291 
    Details
    ISSN: 1573-904X
    Keywords: protein–solvent interaction ; protein stability ; freeze-thawing ; freeze-drying ; hydrophobic interaction
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The stability of proteins is affected by a variety of solvent additives. Sugars, certain amino acids and salts, and polyhydric alcohols stabilize proteins in solution and during freeze-thawing. Urea and guanidine hydrochloride destabilize proteins under either condition. These effects can be explained from the preferential interactions of the cosolvents with the proteins; i.e., the protein stabilizers are preferentially excluded from the proteins, while the destabilizers bind to them. There is a class of compounds, such as polyethylene glycol and 2-methyl-2,4-pentanediol, that destabilize proteins at high temperature but stabilize them during freeze-thawing. Such effects can be accounted for by their preferential exclusion from the native proteins determined at room temperature and from their hydrophobic character, which depends on temperature. During freeze-drying, only a few sugars appear to be effective in protecting proteins from inactivation, as most other stabilizers cannot exert their action on proteins without water. The stabilization is due to hydrogen bonding between the sugars and the dried proteins, the sugars acting as water substitute. Understanding the mechanism of the effects of solvent additives on the protein stability should aid in the development of a suitable formulation for protein.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1015825027737
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