Hello,Back to the Top
Does anyone know the formula of the differential
equation for Higuchi kinetic process? The same for
Peppas.
Thank you,
Vlase Laurian
Dept. of Pharmaceutical Technology and Biopharmaceutics
Faculty of Pharmacy
University of Medicine and Pharmacy "Iuliu Hatieganu"
13, Emil Isac
Cluj-Napoca, Cluj 3400, Romania
vlaselaur.at.yahoo.com
[Vlase, do you have a reference or description for these kinetics - db]
Higuchi kineticis usually used to describeBack to the Top
therelease/dissolution processof drugs from
pharmaceuticals. The kinetics is based on the Fick law
and, on algebraic form, is
%released=k*(t)^0.5
Higuchi kinetic can also describe the
diffusion-controlled absoption of drugs (low
permeability).
Any ideas about the differential form??
Regards,
laurian
Vlase Laurian
Dept. of Pharmaceutical Technology and Biopharmaceutics
Faculty of Pharmacy
University of Medicine and Pharmacy "Iuliu Hatieganu"
13, Emil Isac
Cluj-Napoca, Cluj 3400, Romania
vlaselaur.-at-.yahoo.com
for higuchiBack to the Top
dQ/dt= kd/2*SQRT(t-to)
I recommend you to have a look on this citation
Eur J Pharm Sci. 2001 May;13(2):123-33.
Modeling and comparison of dissolution profiles.
Costa P, Sousa Lobo JM.
PMID: 11297896 [PubMed - indexed for MEDLINE]
nice review with the equations derivation.
hope this helps
Marival
There was a missing parenthesis in the expressionBack to the Top
dQ/dt= kd/(2*SQRT(t-to))
marival
Dear Vlase,Back to the Top
Marival Bermejo wrote;
"for higuchi
dQ/dt= kd/2*SQRT(t-to)"
Please note that you must add parentheses as follows:
dQ/dt= kd/(2*SQRT(t-to))
dQ/dt decreases asymptotically to zero with time.
Best regards,
Hans Proost
Johannes H. Proost
Dept. of Pharmacokinetics and Drug Delivery
University Centre for Pharmacy
Antonius Deusinglaan 1
9713 AV Groningen, The Netherlands
tel. 31-50 363 3292
fax 31-50 363 3247
Email: j.h.proost.aaa.farm.rug.nl
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