Sucrose freeze-dried

FIG. I> Normalized dried product resistance versus thickness of dried product (a) S% w/v sucrose freeze dried in a microbaiance at a temperature of -35 °C, (b) 5% w/v sucrose containing 5% wAv TBA freeze dried in a microbaiance at -35 °C. (Source Kastaian, K., DeLuca, P., PhtamaceuUcal Research, Voi. 12, No. 4,1995 permitted by the Pienum Pubiishing Corporation.)... 

M. Ressing, W. Jiskoot, H. Talsma, C. van Ingen, E. Beuvery, and D. Crommelin, The influence of sucrose, dextran, and hydroxypropyl-beta-cyclodextrin as lyoprotectants for freeze-dried mouse IgG2a monoclonal antibosy (MN12), Pharm. Res., 9, 266... 

Freeze-drying is a relatively gentle way of removing water from proteins in solution. However, this process can promote the inactivation of some protein types, and specific excipients (cryopro-tectants) are usually added to the product in order to minimize such inactivation. Commonly used cryoprotectants include carbohydrates (such as glucose and sucrose), proteins (such as HSA), and amino acids (such as lysine, arginine or glutamic acid). Alcohols/polyols have also found some application as cryoprotectants. 

Enbrel is a product now approved for medical use that is based upon this strategy. The product is an engineered hybrid protein consisting of the extracellular domain of the TNF p75 receptor fused directly to the Fc (constant) region of human IgG (see Box 13.2 for a discussion of antibody structure) The product is expressed in a CHO cell line from which it is excreted as a dimeric soluble protein of approximately 150 kDa. After purification and excipient addition (mannitol, sucrose and trometamol), the product is freeze-dried. It is indicated for the treatment of rheumatoid arthritis and is usually administered as a twice-weekly s.c. injection of 25 mg product reconstituted in WFI. Enbrel functions as a competitive inhibitor of TNF, a major pro-inflammatory cytokine. Binding of TNF to Enbrel prevents it from binding to its true cell surface receptors. The antibody Fc component of the hybrid protein confers an extended serum half-life on the product, increasing it by fivefold relative to the soluble TNF receptor portion alone. 

The frequency at the minimum of this curve is called TOF by the authors. TOF varies with the temperature as shown in Fig. 1.55.6. The extrapolated intersection of the two linear portions identifies the collapse temperature. The predicted Tc by TOF for 10 % sucrose, 10 % trehalose, 10 % sorbitol and 11 % Azactam solution deviates from observations by a freeze-drying microscope (Table 1, from [1.126]) to slightly lower temperatures, the differences are -3 °C, -1.4 °C, 2.2 °C and 0.7 °C. 

De Luca et al. [1.48] showed, that the addition of 5 % tertiary butyl alcohol (tBA) to aqueous sucrose and lactose solutions (up to 40 %) resulted in a frozen matrix, which could be easily freeze dried. De Luca demonstrated by DSC that the melting point rose distinctly (with 60 % solution to -10 °C), but the endothermic of melting returned to 25 %, indicating that not much water had frozen. In solutions with 5 % tBA the exothermic of crystallization became more visible and the melting of tBA could be recognized. 

Kamat et al. [1.85] described a process by which the water content in freeze dried sucrose is measured by infra-red spectroscopy (A = 1000 to 2500 nm) and a newly developed fiber optic (Fig. 1.98). However, whether an interpretation of the absorption lines with respect to the water content is possible must be investigated from product to product. The location of the lines and their relative intensity can prevent their necessary discrimination. For pure... 

De Luca, P. P., Klamat, M. S., Koida, C. Acceleration of freeze-drying Cycles of aqueous Solutions of Lactose and Sucrose with tertiary Buthylalcohol (tBA). Congr. Intern. Technol. Pharm. 5th Vol. 1, p. 439-447, 1989... 

Oesterle, J., Franks, F., Auffret, T. The influence of tertiary butyl alcohol and volatile salts on the sublimation of ice from frozen sucrose solution Implications for freeze drying. Pharmaceutical Developments and Technology, 3 (2), p. 175-183, 1998. Copyright 1998 by Marcel Dekker, Inc., New York, N. Y., USA... 

Remmele et al. [3.55] studied with infrared spectroscopy the structure-hydration behavior of a 49.4 mg/mL lysozyme D20 solution with and without 10 % sucrose. The sample was cooled n in the measuring chamber to -100 °C and then connected to a freeze drying installation, after which the temperature of the sample was raised to +40 °C ... 

During secondary drying, a small RM should be reached, since Tg of the dry product increases with decreasing water content. Tg- of amorphous, freeze dried sucrose increases from 16 °C with 8.5 % RM to 63 °C or 64 °C between 1.0 and 0.7 % RM. It should be taken into account, that RM cannot be taken only at the end of drying, but a possible increase during storage by water desorbed from the stopper has to be considered (see Section 1.3.2 and Pikal et al. [3.7]). 

Microwave-assisted (0.1 or 0.2 Wg-1) convection drying was also applied to osmotically dehydrated blueberries, leading to dried berries that were comparable to freeze-dried ones in much shorter time (Venkatachalapathy and Raghavan, 1998). Frozen blueberries were also dried in a microwave and spouted bed combined dryer (MWSB) after a pretreatment using ethyl oleate and a NaOH dipping solution followed by sucrose osmotic treatment (Feng et al., 1999). Osmotic dehydration prevented the blueberries from... 

Quantitative entrapment of vaccines into small (up to about 200 nm diameter) liposomes in the absence of microfluidization (which can damage DNA and other labile materials when extensive) can be carried out by a novel one-step method (7) as follows SUVs (e.g., cationic) prepared as in section Preparation of Small Unilamellar Vesicles are mixed with sucrose to give a range of sucrose-to-lipid weight/weight ratio of 1.0 to 5.0 and the appropriate amount of plasmid DNA (e.g., 10-500 pg) and/or protein (e.g., up to 1 mg). The mixture is then rapidly frozen and subjected to dehydration by freeze-drying, followed by rehydration as in section Preparation of Vaccine-Containing Dehydration-Rehydration Vesicles. ... 

The content of vaccine within the small liposomes is estimated as in the section Estimation of Vaccine Entrapment in Dehydration-Rehydration Vesicles Liposomes for both microfluidized and sucrose liposomes and expressed as percentage of DNA and/or protein in the mixture subjected to freeze drying as in the section Preparation of Vaccine-Containing Small Liposomes by the Sucrose Method in the case of sucrose small liposomes or in the original DRV preparation (obtained in the section Estimation of Vaccine Entrapment in DRV Liposomes ) for microfluidized liposomes. Vesicle size measurements are carried out by PCS as described elsewhere (6,8,17). Liposomes can also be subjected to microelectrophoresis in a Zetasizer to determine their zeta potential. This is often required to determine the net surface charge of DNA-containing cationic liposomes. 

Fig. 10.—F.t.-I.r. Spectra of Sucrose in Different Physical States. [Quenched melt (QM), freeze-dried (FD), and saturated aqueous solution (SS).]...

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