TY - JOUR

T1 - Ice Recrystallization in a Solution of a Cryoprotector and Its Inhibition by a Protein

T2 - Synchrotron X-Ray Diffraction Study

AU - Zakharov, Boris

AU - Fisyuk, Alexander

AU - Fitch, Andy

AU - Watier, Yves

AU - Kostyuchenko, Anastasia

AU - Varshney, Dushyant

AU - Sztucki, Michael

AU - Boldyreva, Elena

AU - Shalaev, Evgenyi

PY - 2016/7/1

Y1 - 2016/7/1

N2 - Ice formation and recrystallization is a key phenomenon in freezing and freeze-drying of pharmaceuticals and biopharmaceuticals. In this investigation, high-resolution synchrotron X-ray diffraction is used to quantify the extent of disorder of ice crystals in binary aqueous solutions of a cryoprotectant (sorbitol) and a protein, bovine serum albumin. Ice crystals in more dilute (10 wt%) solutions have lower level of microstrain and larger crystal domain size than these in more concentrated (40 wt%) solutions. Warming the sorbitol–water mixtures from 100 to 228 K resulted in partial ice melting, with simultaneous reduction in the microstrain and increase in crystallite size, that is, recrystallization. In contrast to sorbitol solutions, ice crystals in the BSA solutions preserved both the microstrain and smaller crystallite size on partial melting, demonstrating that BSA inhibits ice recrystallization. The results are consistent with BSA partitioning into quasi-liquid layer on ice crystals but not with a direct protein–ice interaction and protein sorption on ice surface. The study shows for the first time that a common (i.e., not-antifreeze) protein can have a major impact on ice recrystallization and also presents synchrotron X-ray diffraction as a unique tool for quantification of crystallinity and disorder in frozen aqueous systems.

AB - Ice formation and recrystallization is a key phenomenon in freezing and freeze-drying of pharmaceuticals and biopharmaceuticals. In this investigation, high-resolution synchrotron X-ray diffraction is used to quantify the extent of disorder of ice crystals in binary aqueous solutions of a cryoprotectant (sorbitol) and a protein, bovine serum albumin. Ice crystals in more dilute (10 wt%) solutions have lower level of microstrain and larger crystal domain size than these in more concentrated (40 wt%) solutions. Warming the sorbitol–water mixtures from 100 to 228 K resulted in partial ice melting, with simultaneous reduction in the microstrain and increase in crystallite size, that is, recrystallization. In contrast to sorbitol solutions, ice crystals in the BSA solutions preserved both the microstrain and smaller crystallite size on partial melting, demonstrating that BSA inhibits ice recrystallization. The results are consistent with BSA partitioning into quasi-liquid layer on ice crystals but not with a direct protein–ice interaction and protein sorption on ice surface. The study shows for the first time that a common (i.e., not-antifreeze) protein can have a major impact on ice recrystallization and also presents synchrotron X-ray diffraction as a unique tool for quantification of crystallinity and disorder in frozen aqueous systems.

KW - calorimetry (DSC)

KW - crystal defects

KW - freeze drying/lyophilization

KW - phase transition

KW - proteins

KW - X-ray powder diffractometry

UR - http://www.scopus.com/inward/record.url?scp=84975842553&partnerID=8YFLogxK

U2 - 10.1016/j.xphs.2016.04.020

DO - 10.1016/j.xphs.2016.04.020

M3 - Article

C2 - 27287516

AN - SCOPUS:84975842553

VL - 105

SP - 2129

EP - 2138

JO - Journal of Pharmaceutical Sciences

JF - Journal of Pharmaceutical Sciences

SN - 0022-3549

IS - 7

ER -