Reiser, Miriam Regina Luise. Effect of continuous phase drug concentration, evaporation and partitioning on transdermal drug permeation kinetics with lipophilic vehicles. 2008, PhD Thesis, University of Basel, Faculty of Science.
Official URL: http://edoc.unibas.ch/diss/DissB_8487
Free emulsifier present in the continuous oil phase affected neither saturation concentration
nor continuous phase drug concentration nor transdermal absorption of the model drugs.
Thickener Aerosil 200 tremendously decreased transdermal permeation of caffeine, but did
not show any interaction with ibuprofen. A reduction of applied dose (0.3 g/cm2 instead of 0.7
g/cm2) did not significantly affect apparent permeability coefficient P-app. Evaporation pattern
of all examined formulations revealed that relative water loss was independent of the
dispersed mass fractions and the employed experimental setup, but increased as the applied
formulation dose was reduced.
For implementing continuous phase drug concentration concept to non-occlusive conditions,
a formula was derived that considered observed water loss and permeated drug amount in
order to calculate the resulting drug concentration in the continuous formulation phase over
time. An increase of the drug concentration in the continuous oil phase was estimated which,
however, did not lead to a measurable increase of the apparent permeability coefficient.
To conclude, the proposed concept considering continuous phase drug concentration can be
used to explain experimentally measured apparent permeability coefficient P-app for lipophilic
vehicles. Applying this concept to w/o-emulsions comprising varying mass fractions provides
a predictive tool in order to delineate the effect of physicochemical formulations parameters
and transdermal drug delivery rate, if occlusive conditions are assumed. In case of nonocclusive
transport conditions, however, evaporation will lead to compositional changes and
consequently changes in continuous phase drug concentration. How these alterations will
affect apparent permeability coefficient using a finite dose requires further investigations.
|Committee Members:||Surber, Christian|
|Faculties and Departments:||05 Faculty of Science > Departement Pharmazeutische Wissenschaften > Pharmazie > Pharmazeutische Technologie (Huwyler)|
|Bibsysno:||Link to catalogue|
|Number of Pages:||182|
|Last Modified:||30 Jun 2016 10:41|
|Deposited On:||13 Feb 2009 16:49|
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