Product continuous freeze-drying

This is one of the reasons for our proposing, some years ago [ 1 ] that pharmaceutical vials be processed in a semicontinuous (similar to the C.Q.C. Plant built by LEYBOLD in the 1960s) or even continuous way, as is done currently, for the mass production of freeze-dried food products and, essentially, for coffee and tea. 

At first sight, then, complex mechanical setups as we propose for semicon-tinuous or continuous freeze-drying seem susceptible to serious hazards in the sterility control of the operation. However, this is not as dramatic as it looks since the essential part of the process—if not the entire process—is carried out automatically and can be done entirely within a sterile environment by remote control. Indeed, today highly sophisticated automation can be achieved if we resort to the advanced technologies developed for the nuclear industry and profit by the experience of their operators. However, this sophistication will definitely bear on the cost and this can be a serious drawback for conventional low-priced products. 

The competitive nature of the food and beverage industry and the need for continued improvements in cost-effective manufacturing have provided an impetus for companies to develop and use new bioseparation techniques at very large scales, for example, freeze-drying in coffee production and continuous centrifugation in brewing. 

Evidence continues to accumulate in the literature attesting to loss in product potency or activity associated with elevated moisture content in freeze-dried products. 

Hg are reached. The curves in Fig. 3 show the change in resistivity, observed in such an experiment, as a function of the equilibrium hydrogen pressure and of the total amount of hydrogen reacted. (The hydrogen was kept very dry in this experiment by continuously freezing the product water.) The resistivity increased by a factor of 100 before an equilibrium pressure of 3 mm. was reached, and it had increased by a factor of almost 10 at a pressure of 80 mm. Similarly, even after half the total amount of 710 moles of hydrogen per g. had reacted, the equilibrium pressure was too small to be conveniently measured 70% of the total amount had already reacted by the time the hydrogen pressure was 3 mm. 

The active ferrocenylethanoic N-hydroxysuccinimide ester was prepared in situ from ferrocenylethanoic acid (1.0 mmolj, HSU (1.1 mmol), and DCC (1.2 mmol) in THF (2 ml) at -5 C (Ih) and ambient temperature (5h). The ester solution, filtered from the urea by-product, combined with the THF washings of the residue, and reduced in volume to 7 ml, was added dropwise to the precooled (0 ) solution of copolyamide 5 (x/y = 3.0 0.7 mmol) in H2O (5 ml) with rapid stirring. Following the addition of more THF (1 ml) to dissolve some precipitated active ester, the mixture was stirred for 18h at ambient temperature. Upon the addition of NEts (1.0 mmol), stirring was continued for another 6h, the THF component removed under reduced pressure, and the mixture diluted with H2O (8 ml). The filtered solution was dialyzed and freeze-dried as before to give 12 as a w ater-soluble, brown solid. Yield, 78% 77inh(H20) 12 ml g l. Anal, found Fe, 2.6%. Calcd. for 12 (x/y = 3.0 45% substitution) Fe, 2.7%. 

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