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Partially crystalline systems in lyophilization: II. Withstanding collapse at high primary drying temperatures and impact on protein activity recovery

Authors

  • Koustuv Chatterjee,

    1. College of Pharmacy, 308, Harvard St. S.E., University of Minnesota, Minneapolis, Minnesota 55455
    Current affiliation:
    1. Amgen Inc., 1 Amgen Center Drive Thousand Oaks, CA 91320.
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  • Evgenyi Y Shalaev,

    1. Pfizer Groton Laboratories, Eastern Point Road Groton, Connecticut
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  • Raj Suryanarayanan

    Corresponding author
    1. College of Pharmacy, 308, Harvard St. S.E., University of Minnesota, Minneapolis, Minnesota 55455
    • College of Pharmacy, 308, Harvard St. S.E., University of Minnesota, Minneapolis, Minnesota 55455. Telephone: 612-624-9626; Fax: 612-626-2125.
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Abstract

In an accompanying article we have described the construction of the water-rich sections of raffinose–glycine–water and trehalose–glycine–water state diagrams. In this study, we use the information obtained from the state diagrams to identify the minimum weight fraction of the crystalline component in glycine–carbohydrate systems necessary to withstand collapse at high primary drying temperatures. We also determine the impact of primary drying, substantially above equation image, on the recovery of lactate dehydrogenase (LDH) activity. Ambient and variable temperature X-ray powder diffractometry and differential scanning calorimetry were used to characterize the frozen and freeze-dried systems. Aqueous solutions with glycine to carbohydrate (raffinose pentahydrate or trehalose dihydrate) weight ratios ranging from 0.2 to 2.0 were freeze dried. The protein formulations contained 20 mM citrate buffer (pH 6.0) and LDH (20 μg/mL). A glycine to anhydrous raffinose weight ratio ≥1.18 and a glycine to anhydrous trehalose weight ratio ≥1.56 were necessary to withstand macroscopic collapse in the system, when the primary drying was carried out at a product temperature at least 10°C above the equation image. The recovery of LDH activity was almost complete in the reconstituted lyophile whether the primary drying was carried out above equation image (−10°C) or below equation image (−32°C). Thus, by judiciously combining crystalline and amorphous components, it was possible to primary dry at temperatures substantially above the equation image. © 2005 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 94:809-820, 2005

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