کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
2085729 | 1545408 | 2007 | 14 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: Morphology of protein particles produced by spray freezing of concentrated solutions Morphology of protein particles produced by spray freezing of concentrated solutions](/preview/png/2085729.png)
The mechanisms for the formation of high surface area lysozyme particles in spray freezing processes are described as a function of spray geometry and atomization, solute concentration and the calculated cooling rate. In the spray freeze-drying (SFD) process, droplets are atomized into a gas and then freeze upon contact with a liquid cryogen. In the spray freezing into liquid (SFL) process, a solution is sprayed directly into the liquid cryogen below the gas–liquid meniscus. A wide range of feed concentrations is examined for two cryogens, liquid nitrogen (LN2) and isopentane (i-C5). The particle morphologies are characterized by SEM micrographs and BET measurements of specific surface area. As a result of boiling of the cryogen (Leidenfrost effect), the cooling rate for SFL into LN2 is several orders of magnitude slower than for SFL into i-C5 and for SFD in the case of either LN2 or i-C5. For 50 mg/mL concentrated feed solutions, the slower cooling of SFL into LN2 leads to a surface area of 34 m2/g. For the other three cases with more rapid cooling rates, surface areas were greater than 100 m2/g. The ability to adjust the cooling rate to vary the final particle surface area is beneficial for designing particles for controlled release applications.
Journal: European Journal of Pharmaceutics and Biopharmaceutics - Volume 65, Issue 2, February 2007, Pages 149–162