Jl. Cleland et al., A specific molar ratio of stabilizer to protein is required for storage stability of a lyophilized monoclonal antibody, J PHARM SCI, 90(3), 2001, pp. 310-321
The selection of the appropriate excipient and the amount of excipient requ
ired to achieve a 2-year shelf-life is often done by using iso-osmotic conc
entrations of excipients such as sugars (e.g., 275 mM sucrose or trehalose)
and salts. Excipients used for freeze-dried protein formulations are selec
ted for their ability to prevent protein denaturation during the freeze-dry
ing process as well as during storage. Using a model recombinant humanized
monoclonal antibody (rhuMAb HERS), we assessed the impact of lyoprotectants
, sucrose, and trehalose, alone or in combination with mannitol, on the sto
rage stability at 40 degreesC. Molar ratios of sugar to protein were used,
and the stability of the resulting lyophilized formulations was determined
by measuring aggregation, deamidation, and oxidation of the reconstituted p
rotein and by infrared (IR) spectroscopy (secondary structure) of the dried
protein. A 360:1 molar ratio of lyoprotectant to protein was required for
storage stability of the protein, and the sugar concentration was 3-4-fold
below the iso-osmotic concentration typically used in formulations. Formula
tions with combinations of sucrose (20 mM) or trehalose (20 mM) and mannito
l (40 mM) had comparable stability to those with sucrose or trehalose alone
at 60 mM concentration. A formulation with 60 mM mannitol alone provided s
lightly less protection during storage than 60 mM sucrose or trehalose. The
disaccharide/mannitol formulations also inhibited deamidation during stora
ge to a greater extent than the lyoprotectant formulations alone. The reduc
tion in aggregation and deamidation during storage correlated directly with
inhibition of unfolding during lyophilization, as assessed by IR spectrosc
opy. Thus, it appears that the protein must be retained in its native-like
state during freeze-drying to assure storage stability in the dried solid.
Long-term studies (23-54 months) performed at 40 degreesC revealed that the
appropriate molar ratio of sugar to protein stabilized against aggregation
and deamidation for up to 33 months. Therefore, long-term storage at room
temperature or above may be achieved by proper selection of the molar ratio
and sugar mixture. Overall, a specific sugar/protein molar ratio was suffi
cient to provide storage stability of rhuMAb HER2. (C) 2001 Wiley-Liss, Inc
.