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Excipients devitrification

Despite these precautions, a slow freezing process is not always sufficient to ensure a dimensionally stable pellet of good cosmetic appearance. In this respect, formulated solutions that produce interstitial metastable glasses on cooling are sometimes a source of problems. In such systems, devitrification followed by partial erratic recrystallization of the excipient may occur during lyophilization, thereby generating a pellet of poor powdery appearance. [Pg.376]

The remedy to this situation is to perform a thermal treatment of the frozen solution. This treatment consists of a controlled rewarming of the solution until devitrification and recrystallization of the excipient occurs, followed by a last freezing step below the solidification temperature. A typical excipient justifiable of such a treatment on thermodynamic grounds is mannitol. In the absence of proteins that maintain the structural integrity of the pellet, mannitol solutions often yield cakes of poor appearance. The induction of mannitol crystallization by rewarming around -25°C evades this problem and allows one to obtain elegant pellets that are easy to lyophilize and do not shrink. [Pg.376]


See other pages where Excipients devitrification is mentioned: [Pg.99]    [Pg.99]    [Pg.124]    [Pg.551]    [Pg.552]   
See also in sourсe #XX -- [ Pg.99 ]




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