X-Message-Number: 8429 From: Brian Wowk <> Date: Thu, 31 Jul 1997 20:52:52 -0500 (CDT) Subject: Melting points, etc. Regarding the recent questions about the melting point of adonitol: It is generally true in chemistry that when you mix two compounds together, the resultant solution has a melting point lower than that of either component. For example, pure glycerol and DMSO have melting points close to room temp. But 65% solutions in water don't solidify until somewhere near -100'C. So a high melting point does not immediately disqualify an agent as a cryoprotectant. About adonitol in particular, adonitol (1,2,3,4,5 penta- hydroxypentane) is a huge molecule that costs $2 per gram. Although I haven't consulted Doug's permeability reference yet, it's almost certainly going to be less permeant and more viscous than glycerol. And glycerol is already almost intolerably viscous and non-permeant for cryoprotection by perfusion (as distinct from cryoprotection of cell suspenstions in solution). *************************************************************************** Brian Wowk CryoCare Foundation 1-800-TOP-CARE President Human Cryopreservation Services http://www.cryocare.org/cryocare/ --------------------------------------------------------------------------- Rate This Message: http://www.cryonet.org/cgi-bin/rate.cgi?msg=8429