Dear All,
There are lots of mathematical model in dissolution of drug. One of which is called Weibull. Any one aware what is the concept behind the model?
I am not asking for equation but about the concept behind this model.
Thanks in advance
Dear Ramkumar,
You find the answer in this thesis:
http://is.muni.cz/th/150893/prif_m/mthesisv2_final_corrected.pdf
Dear Ewalds,
Thanks for your reply.
As per the article you shared it states that "the dissolution never ends in this model and there is always infinitely small amount of undissolved substance. Practically as an end of the dissolution we could consider again the time instant when 99% of the solvent is dissolved."
But it did not highlight how the drug is being released / mechanism of drug release as per this model. Can you capture it in this article or some where?
Thanks
Weibull is more sensitive and explanatory for release behavior and in determination between differences of two dissolution profiles.
Check Weibull out from this paper:
International Journal of Pharmacy and Pharmaceutical Sciences
ISSN- 0975-1491 Vol 5, Issue 3, 2013
STATISTICAL EVALUATION OF IN-VITRO DISSOLUTION PROFILES OF DIFFERENT BRANDS OF SIMVASTATIN 20 MG TABLETS AVAILABLE IN LOCAL MARKET OF KARACHI
SAKINA FATIMA, SHAHNAZ USMAN2, IYAD NAEEM MUHAMMAD
" Among all brands Weibull model fits best model to the dissolution data, considered high determination coefficient (R2) whereas first order and Hixson Crowell failed to be fit (< 0.98). "
More: Langenbucher, F. Linearization of dissolution rate curves by the Weibull distribution. J. Pharm. Pharmacol. 1972; 24:979-981
Hi
The Weibull is simply a mathematical function (with some variants) which can be used via fitting of its parameters to capture a dissolution curve (or more generally a curve from other types experimental measurements). There is no mechanism associated with this approach and thus it is not possible to extrapolate to different experimental conditions (pH, fluid volume etc, etc). This is important where dissolution (release) is sensitive to physiological variability (of pH, fluid volume,gut wall permeability etc) in vivo.
regards
David
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