Pharmacokinetics: Volume of Distribution and Total Body Clearance

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Discussion Overview

The discussion revolves around the concepts of total volume of distribution and total body clearance in pharmacokinetics. Participants explore the definitions, formulas, and intuitive connections between these concepts, as well as the availability of educational resources on the topic.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Meta-discussion

Main Points Raised

  • One participant seeks clarification on the formula for total volume of distribution, questioning if it is correctly defined as V_c = D/C_p(0).
  • The same participant expresses confusion about the relationship between total volume of distribution and total body clearance, represented as Cl_total = k_e V_c.
  • Another participant suggests that finding comprehensive resources may be challenging and recommends looking for alternative textbooks or articles, including a Wikipedia page on clearance in pharmacology.
  • A later reply acknowledges the usefulness of online materials but notes personal limitations in accessing textbooks, indicating a reliance on available online resources.
  • One participant comments on the variability of textbook availability among students and suggests that sharing personal educational circumstances may elicit more tailored responses from others in the discussion.

Areas of Agreement / Disagreement

Participants do not reach a consensus on the clarity of the concepts discussed. There is a mix of support for seeking additional resources and acknowledgment of the challenges in accessing comprehensive educational materials.

Contextual Notes

Participants express uncertainty regarding the definitions and relationships between pharmacokinetic concepts, indicating that their understanding may depend on specific course contexts or available resources.

Master1022
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Homework Statement
What is the meaning behind the total volume of distribution and total body clearance concepts?
Relevant Equations
Concentration equations
Hi,

I was recently reading through Systems Kinetic Modeling notes and am struggling to understand the concepts of total volume of distribution and total body clearance.

As far as I understand, the total volume of distribution ## V_c ## is the "volume of the compartment into which the substance has distributed itself" and can be written as:
V_c = \frac{\text{Dose given}}{\text{Initial concentration}} = \frac{D}{C_p (0)}
is this correct?

Then, I don't understand the intuition between the connection between ## V_c ## and the total body clearance ## Cl_{total} ##, which can be written as ## Cl_{total} = k_e V_c ## where ## k_e ## is the elimination rate. We weren't told about it during the lectures and I just found the formulae above on the internet.

Is this because the total body clearance is supposed to measure the volume of substance within the plasma that is cleared per unit time?

Any help would be greatly appreciated.
 
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Maybe somebody will spell it out for you, but don't count on it. It is hard work for anyone to actually replace, write from scratch, textbooks. If one book or source is not adequate look for another. There seems to me quite a good and thorough article on Wikipedia https://en.wikipedia.org/wiki/Clearance_(pharmacology)

I hope you realize the connection between this and your previous question of about a week ago that I hope to come back on, unfortunately I am pretty short of time.
 
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epenguin said:
Maybe somebody will spell it out for you, but don't count on it. It is hard work for anyone to actually replace, write from scratch, textbooks. If one book or source is not adequate look for another. There seems to me quite a good and thorough article on Wikipedia https://en.wikipedia.org/wiki/Clearance_(pharmacology)

I hope you realize the connection between this and your previous question of about a week ago that I hope to come back on, unfortunately I am pretty short of time.
Thanks @epenguin, will take a look at that! I agree that using materials online is helpful, but am unfortunately unable to access such textbooks at this time. However, I am sure this topic is taught widely enough that there will be plenty of other resources for me online (wikipedia page looks pretty helpful from a first glance)
 
Widely taught, yes and no. It seems part of a much more general course you are doing. By no means every student everywhere will have a textbook including this and rarely more than one, though they may have more availability in libraries. If you amplify a little the account of yourself and studies on your personal page, maybe say where you are, any special circumstances, helpers here will likely take it into account. I will try add a little to other thread later today or tomorrow.
 
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