TY - JOUR
T1 - Effects of Excipient Interactions on the State of the Freeze-Concentrate and Protein Stability
AU - Jena, Sampreeti
AU - Horn, Jacqueline
AU - Suryanarayanan, Raj
AU - Friess, Wolfgang
AU - Aksan, Alptekin
N1 - Publisher Copyright:
© 2016, Springer Science+Business Media New York.
PY - 2017/2/1
Y1 - 2017/2/1
N2 - Purpose: The physical state of excipients in freeze-dried formulations directly affects the stability of the active pharmaceutical ingredient (API). Crystallization of trehalose and mannitol in frozen solutions has been shown to be a function of composition. However, to date a detailed study of the effect of concentrations of the API and other excipients on the crystallinity of mannitol and trehalose in frozen solutions has not been reported. Methods: The crystallinity of mannitol and trehalose in frozen solutions was characterized by Differential Scanning Calorimetry, X-ray diffractometry, and FTIR spectroscopy. The secondary structure of BSA was probed by FTIR, and Circular Dichroism spectroscopy in frozen and thawed solutions, respectively. Results: Trehalose crystallization was accompanied by unfolding of BSA. BSA delayed and reduced the extent of mannitol and trehalose crystallization. Similar effects were observed upon adding D2O (≥5% w/w) and low concentrations of polysorbate 20 (≤0.2% w/w) with retention of BSA in its native conformation. At high BSA to trehalose mass ratio, the protein could stabilize itself in the frozen state, but unfolded upon thawing. Conclusions: The API and other excipients, in a concentration-dependent manner, influenced the physical state of the freeze concentrate as well as the stability of the API.
AB - Purpose: The physical state of excipients in freeze-dried formulations directly affects the stability of the active pharmaceutical ingredient (API). Crystallization of trehalose and mannitol in frozen solutions has been shown to be a function of composition. However, to date a detailed study of the effect of concentrations of the API and other excipients on the crystallinity of mannitol and trehalose in frozen solutions has not been reported. Methods: The crystallinity of mannitol and trehalose in frozen solutions was characterized by Differential Scanning Calorimetry, X-ray diffractometry, and FTIR spectroscopy. The secondary structure of BSA was probed by FTIR, and Circular Dichroism spectroscopy in frozen and thawed solutions, respectively. Results: Trehalose crystallization was accompanied by unfolding of BSA. BSA delayed and reduced the extent of mannitol and trehalose crystallization. Similar effects were observed upon adding D2O (≥5% w/w) and low concentrations of polysorbate 20 (≤0.2% w/w) with retention of BSA in its native conformation. At high BSA to trehalose mass ratio, the protein could stabilize itself in the frozen state, but unfolded upon thawing. Conclusions: The API and other excipients, in a concentration-dependent manner, influenced the physical state of the freeze concentrate as well as the stability of the API.
KW - crystallization
KW - freeze-drying
KW - glass transition
KW - mannitol
KW - trehalose
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U2 - 10.1007/s11095-016-2078-y
DO - 10.1007/s11095-016-2078-y
M3 - Article
C2 - 27981449
AN - SCOPUS:85006098433
SN - 0724-8741
VL - 34
SP - 462
EP - 478
JO - Pharmaceutical research
JF - Pharmaceutical research
IS - 2
ER -