Modelling in Herbal formulations

  • As adequately explained by Dr. Adeniyi during the Webinar, one of the limitations of developing a model for herbal drugs is because of the multiple and often unidentified active ingredients such formulations contain. Nonetheless, is it not possible to model based exclusively on the pharmacodynamics (not PK or PK/PD), particularly the response following its administration to a population of patients?

    Hi Fidelis,

    Good to hear from you again.
    While one could use a “kinetics of drug effects” approach, I have not seen it used for herbal drugs. What would be the research question that you’d want the model to answer?

    See this description by Jacqmin et al https://www.ncbi.nlm.nih.gov/pubmed/17051439
    Here a virtual compartment representing the biophase in which the concentration is in equilibrium with the observed effect is used to extract the (pharmaco)kinetic component from the pharmacodynamic data alone. Parameters of this model are the elimination rate constant from the virtual compartment (KDE), which describes the equilibrium between the rate of dose administration and the observed effect, and the second parameter, named EDK50 which is the apparent in vivo potency of the drug at steady state, analogous to the product of EC50, the pharmacodynamic potency, and clearance, the PK “potency” at steady state.

    My co-authors and I used this approach for a bisphosphonate – see DOI: 10.1111/j.1365-2125.2004.02224.x

    You could also check out the work described in Gabrielson and Weiner’s textbook on Dose-Response-Time models, and applications in a few cases including ophthalmology.

    Let us know how this works out,

    Colin

    Dear Colin,
    Thank you for this response. I will take time to go through all these references when day breaks and revert back to you. However, i was thinking of a situation whereby one can use body temperature, blood glucose level etc to study the kinetic effects of an antipyretic or hypoglycemic herbal formulation.
    Thank you very much.
    Fidelis

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