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Dear all
I would be happy to hear your thoughts on controlling the volume vs.
concentration of a subcutaneous injectable biological going into an
escalating single dose first in man study. Is it better to keep the
injected volume constant and increase drug concentration as the dose
increases, or keep the concentration constant and increase volume.
Many thanks,
Ofer
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The subcutaneous chamber is compliant but is also reactive. If you
change the volume you are increasing the surface area of the bolus as
well as the discomfort to the subject. SC routes are also among the
best for stimulating an immune response, so that should be a
consideration as well.
I would go with controlling the volume.
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No. I suggest keeping the volume constant
--
Edward F. O'Connor
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You might see a lower rate of absorption for a small volume at a
higher concentration, compared to a larger volume at low
concentration, because of the smaller surface area for absorption with
small injection volumes. I don't know how much it affects extent of
bioavailability. The manufacturing and dose solution preparation are
less complicated if you keep concentration constant and increase
volume. Keep in mind that the vialed protein concentration should be
selected so that the dose volume is not less than 0.05 mL (it becomes
hard to accurately dose below that volume) but also not greater than
1.0 mL (difficult to inject more than that volume at a single site).
For a dose escalation trial, you may need to vial at two different
concentrations to stay within those criteria.
Cynthia Sung, Ph.D.
Rainbow Pharma Consulting
email: csung.at.rainbowpharmaconsult.com
URL: www.rainbowpharmaconsult.com
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