[RASMB] Malvern Viscosizer

Fri Jun 5 05:59:45 PDT 2015

Please note that I forgot which email was registered to RASMB.  This is an exact copy of my previous email, sent earlier, but delayed because of my email mixup.
Thanks to all who have already responded with excellent questions, information and explanations.  
Quite a bit of other work has delayed a full response, though I do have time to say quickly that I forgot Vladmir's paper on using the beads with DLS even though an intern started to implement this here last summer as part of a viscosity project. We have a Wyatt plate reading DLS already, so the reminder is very helpful.
The response to Steve Harding is also simple:  thanks much.  It is obvious to me that I need some time to digest and think about intrinsic viscosity more. 
For John Sumida, I can say that now that I am in research, the final question about viscosity is this:  Can and should research throw out some leads because of viscosity problems?  Formulation colleagues are being asked to make 100 or 150 mg/ml solutions which must be syringeable.  Manufacturing colleagues use lower concentrations (though local concentrations on some filters can get pretty high), but have little flexibility in buffer additions that formulators can use solve some problems.  In research the question is whether we can screen viscosity reliably with limited amounts of material and little time to try lots of excipients, and whether or not an otherwise good molecule could have really un-solvable viscosity problems.
Sorry if I missed anyone by name.  I will re-read all the responses eventually.
Kind Regards,
David Hayes
      From: "david.hayes at boehringer-ingelheim.com" <david.hayes at boehringer-ingelheim.com>
 To: rasmb at rasmb.org 
 Sent: Tuesday, June 2, 2015 12:06 PM
 Subject: [RASMB] Malvern Viscosizer

Hi all (especially hoping Steve Harding is active),    I recently saw the Malvernviscosizer.  It is a capillary viscometer andtaylor dispersion instrument. (Taylor dispersion looks at the diffusion pattern of a small plug of sample in a capillary). Because of the small volumes used, it could be useful for screening early limited supply proteins for viscosity problems.    Are there any general thoughts on the technology?    I remember Steve Harding telling us at BITC that you never use rolling ball viscometers on proteins: the proteins stick to the ball. Recently we found out here that the regular AntonPaar cone and plate rheometers sometimes need PS-80 in protein samples or the air water interface around the outside edge can predominate the viscosity measurements.    I did ask whether most samples just stick to the capillary and disappear or run anomalously, but the answer was they had a super coating so most things won’t stick. This coating makes the capillary impossible to clean (so you buy more capillaries from Malvern). And that the taylor dispersion fitting will tell you if and approximately how much the sample interacts with the capillary walls.    Kind Regards,    David Hayes 
_______________________________________________
RASMB mailing list
RASMB at list.rasmb.org
http://list.rasmb.org/listinfo.cgi/rasmb-rasmb.org

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://list.rasmb.org/pipermail/rasmb-rasmb.org/attachments/20150605/55c7fea2/attachment-0001.htm>