I have been following the various changes that have occurred in
determining the content of chondroitin sulfate by the USP method. Such
changes have been the the use of a new reference standard (USP
Chondroitin Sulfate RS), the incorporation of a standard curve USP 27 of
(0.4mg/mL, 0.8mg/mL and 1.2mg/mL of the standard) to a new standard
curve in the USP 28 of (0.5mg/mL, 1.0mg/mL and 1.5mg/mL of the standard)
as well as a change in the buffer from sodium phosphate to now a
potassium phosphate. The questions I have is can anyone explain the
benefits of the new changes especially the incorporation of a curve as
well as a change in the buffer? I have heard from some that gowing from
USP 26 which had no curve for the standard to USP 27 that incorporates a
curve for the standard that their content of chondroitin sulfate in
their product has dropped ~3%. I would like to hear from all on the
advantages and disadvantages from all the changes that have occurred
from the USP testing of chondroitin sulfate.
Dana Summers
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