Back to the Top
We are using an oral formulation of 0.5% HPMC with 10% cremophor RH40
for PK and tox studies, each of these studies is at a different CRO.
When one CRO prepares the vehicle, the vehicle is clear. When the
other CRO prepares the formulation, the vehicle is cloudy and the
cremophor settles to the bottom. As far as we can tell, the methods
of preparation were identical. Although the HPMC was purchased from
separate suppliers, examination of the paperwork (CAS #, viscosity,
cps value) indicates that they are the same substance.
Has anyone had experience where the grade or viscosity of HPMC in an
oral formulation affects the exposure?.
Back to the Top
In aqueous system, the solubilization of a substance might be related
to the surfactant (i.e. cremophor RH 40) micelles formation to form a
thermodynamically stable isotropic solution (limpid). If the
surfactant settles to the bottom of the flask, there is no micelles
formation, available to dissolve properly the drug. The drug is then
partially solubilized, leading to cloudy vehicle.
It is very important to make a clear solution of the surfactant in
water before adding the drug to the system.
If the surfactant solution is not clear, the viscosity of the final
system might be different as HPMC, surfactant and water interact with
Regarding the HPMC, difference in grade or viscosity, would affect the
substance solubilization process but drug dissolution and exposure as
Hope this reply may be of your interest.
Want to post a follow-up message on this topic?
If this link does not work with your browser send a follow-up message to PharmPK@boomer.org with "Grade or viscosity of HPMC" as the subject
Support PharmPK by using the
Copyright 1995-2011 David W. A. Bourne (firstname.lastname@example.org)