Secondary Structure Characterization of Microparticulate Insulin Powders†

Yeo, Sang‐Do; Debenedetti, Pablo G.; Patro, Sugunakar Y.; Przybycien, Todd M.

doi:10.1002/jps.2600831203

Cited by 71 publications

(51 citation statements)

References 37 publications

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“…For RNase A, chymotrypsinogen, and insulin, only minor decreases in the a-helix content but substantial increases in the fl-sheet content took place upon lyophilization. For lyophilized insulin, these dehydrationinduced structural changes are in line with recent Raman spectroscopy findings comparing bovine Zn-insulin powders with those dissolved in aqueous solutions (52). Note that for all three proteins the percentage of the unordered structures drops upon lyophilization indicating an overall increase in the structural order.…”

supporting

confidence: 86%

Lyophilization-induced reversible changes in the secondary structure of proteins.

Griebenow

Klibanov

1995

Proc. Natl. Acad. Sci. U.S.A.

349

311

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Changes in the secondary structure of some dozen different proteins upon lyophilization of their aqueous solutions have been investigated by means of Fouriertransform infrared spectroscopy in the amide IHI band region. Dehydration markedly (but reversibly) alters the secondary structure of all the proteins studied, as revealed by both the quantitative analysis of the second derivative spectra and the Gaussian curve fitting of the original infrared spectra. Lyophilization substantially increases the ,8-sheet content and lowers the a-helix content of all proteins. In all but one case, proteins become more ordered upon lyophilization.Consider the common laboratory and bioindustrial process of lyophilization or freeze-drying of aqueous solutions of proteins. Suppose that this lyophilization is carried out such that no irreversible damage to the protein ensues-i.e., when the lyophilized protein is redissolved in water, it exhibits the same properties as prior to lyophilization. The question still remains whether the protein structure in the lyophilized form is native or whether the lyophilization has resulted in reversible protein denaturation. Apart from its biochemical interest, the answer has important biotechnological implications. For example, proteins that have been lyophilized (which is how research and pharmaceutical protein preparations are usually stored) undergo moisture-triggered aggregation (1). To understand the mechanism of this undesirable phenomenon and to develop rational strategies for its prevention, structural information on proteins in the solid-e.g., lyophilized-form is needed. In addition, lyophilized enzymes suspended in organic solvents have proven to be useful synthetic catalysts (2); enzyme structural data should help maximize their performance.The issue of protein conformation in the lyophilized form is controversial. For example, the results of Fourier-transform infrared (FTIR) spectroscopic investigations of hen egg-white lysozyme were interpreted to indicate that lysozyme structure in either aqueous solution or the lyophilized state is the same (3-6). This conclusion was supported by some hydrogen isotope-exchange studies (6, 7) but contradicted by others (8). Raman (9-11) and solid-state NMR (12) studies have suggested significant (reversible) structural changes occurring in lysozyme upon lyophilization. Likewise, recent hydrogen isotope-exchange/high-resolution NMR (13) and FTIR (14,15) investigations of various proteins strongly point to lyophilization-induced reversible denaturation.Recent advances, both instrumentational and conceptual, in FTIR spectroscopy make it a method of choice for examining the structure of solid proteins. This has been illustrated by the scholarly work of Prestrelski et al. (14,15), who have employed this methodology to quantify changes in the secondary structure of proteins caused by lyophilization. Using the second derivatives of the vibrational spectra of proteins in the amide I band region (1600-1720 cm-1), these authors have calculated so-call...

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supporting

confidence: 86%

Lyophilization-induced reversible changes in the secondary structure of proteins.

Griebenow

Klibanov

1995

Proc. Natl. Acad. Sci. U.S.A.

349

311

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“…The biological activity of the insulin powder was also shown by in-vivo studies to be unchanged. Raman spectroscopy further confirmed the maintenance ofthe secondary structure ofthe protein [47].…”

Section: )mentioning

confidence: 71%

“…Gas antisolvent techniques have also been used for the production of micron-sized particles of proteins suitable for inhalation delivery, such as insulin [ 18,45,47], catalase [43,46], trypsin and lysozyme [49,68]. Catalase precipitated as 111m spherical and rectangular particles whereas insulin formed both agglomerated nanospheres and 1 11m thick needles 5 11m in length.…”

Section: )mentioning

confidence: 99%

Recent Applications of Supercritical Fluid Technology to Pharmaceutical Powder Systems

Bustami

Chan

Dehghani

et al. 2001

KONA

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“…SC antisolvent method has great potential for processing of pharmaceuticals (Mosqueira et al 1981;Steckel et al 1997) and labile compounds such as proteins Winters et al 1999;Yeo et al 1994;Yeo et al 1993) and to obtain various morphologies of biopolymers (Bleich et al 1996;Debenedetti et al 1993;Dixon and Johnstone 1993;Reverchon 1999;Subramanian et al 1997), such as microspheres (Falk et al 1997) threads, fibers, networks (Dixon and Johnstone 1993), sponges, foams, and films. One of the advantages of using SCF in polymer processing is the possibility of producing different solid shapes and structures at low temperature with a minimum amount of residual organic solvents.…”

Section: Production Of Different Morphologies Of Biocompatible Polymersmentioning

confidence: 99%

Supercritical Fluid Application in Food and Bioprocess Technology

Mozafari¹

2011

Mass Transfer - Advanced Aspects

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Secondary Structure Characterization of Microparticulate Insulin Powders†

Cited by 71 publications

References 37 publications

Lyophilization-induced reversible changes in the secondary structure of proteins.

Lyophilization-induced reversible changes in the secondary structure of proteins.

Recent Applications of Supercritical Fluid Technology to Pharmaceutical Powder Systems

Supercritical Fluid Application in Food and Bioprocess Technology

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