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I think you are trying to squeeze more out of a series of videos on the basics of pharmacokinetics than was intended. The bottom line is that to try and apply another route of admin in the circumstances described, would not apply.

@@GrahamLappin 😄😄😄 Anyways, what would be your recommendations for me to know more. I'm an undergraduate student at Makerere university pursuing a bachelors in pharmacy. Do you think I need that more at this level? I love pharmacokinetics

At a basic level you are correct but other factors can come into play. Remember CL(int) is determined in vitro, in the absence of any plasma or cellular binding effects (hence the term intrinsic). Also blood binding can have an effect and this this was not covered. The video was intended as a basic introduction and so be careful how far you use it for interpretations.

@@GrahamLappin okay thanks🤝

For simplicity, assume the shape of the concentration-time curve on the semi-log plot is a triangle. (ignore the absorption phase on the oral dose). The linear trapezoidal rule assumes the hypotenuse is a straight line, but it is only a straight line when concentration is on a log scale. The log trapezoidal rule takes account of this and hence provides a better estimate of the AUC. Hope this helps?

@@GrahamLappin I'm trying to but let me put it this way why [(A-B)/(InA-InB)]*(D-C) AND NOT [(InA+InB)/2]*(D-C)

@@KigongoFelix You are asking for the mathematical derivation of the equation - which is something I didn't intend to include. In fact, I've not done this for many years and so I'll struggle to answer this. There are explanations on line, but the mathematics is quite involved.

@@GrahamLappin Alright

Thanks

Very pleased it helped.

yes - it's a typo and indeed at about 25:13, CYP 2E1 is attributed. Your correction is appreciated.

On the most basic level, AUC 0-inf is the most important parameter as its used to calculate other PK parameters such as CL. Also at the most basic level, AUC 0-t is used to calculate the extrapolation to AUC 0-inf (see around 17:20 in the video).

I think the units are confusing you. The units are based on multiplying the X and Y axes of the plot. The X axis is hours and the Y axis is ng/mL, so the area in ng/mL x h. You have to define the time period over which the AUC is measured. Let's say it's 0-infinity, then the total area under the curve from the point the drug is administered IV (time 0) to the point it has all been cleared from the plasma. In your example this would be 10 ng/ml x h (total AUC)

Sorry but I'm now retired. The book and a new version of TH-cam videos to go with them is my final pharmacokinetic venture.

Unfortunately I have no control on where Amazon offers its books. As I understand it, the ebook should be available but the paperback is not - is that correct? I am looking into other options in respect to the paperback but this will take some time and those options seem limited.

I am making enquiries with contacts I have in India to see if anything can be done. It might take a little while.

I'm not sure I fully understand your question, but the Pb to Pb ratio in meteorites is the same as on Earth for rocks of the same age. Patterson's Pb-Pb dating carried out in 1956 was using meteorites.

Thank you for your kind words. Two things should be happening in the next 12-months. (1) A colleague and I are writing a textbook of pharmacokinetics based on the videos which we will self-publish to keep the cost as low as possible. (2) The videos are being re-done so they more comprehensive.

No kickbacks I'm afraid. Actually I'm not in it for the money, I'm only too pleased to spread the educational word as best I can.

I have attempted to do this to some extent in the latest video, on drug interactions.

@@GrahamLappinThank you for your reply. Yes, I watched it. The examples you mentioned are helpful. I am new to this field of science, and I would like to learn more especially Ki, Kinact and IC50 shift assays and analysis of results. Caco2 and MDCK assays are little easier to understand, but I am sure I still have more to learn. Your advise and suggestions are most welcome.

@@rathnadurgar2421 You're getting into areas where I have little direct experience and as such, I'm reluctant to try to do videos on them.

@@GrahamLappin Okay thank you! In case if there is any book you came across which is reasonably good for a newcomer (nor too basic neither too advanced) then please let me know. Thanks again! Wish to see more and more beneficial videos from you!

Log-P is often quoted for drugs but log-D requires values at different pH values and so I am not aware of any database giving those.

@@GrahamLappin Does Log P value also changes with pH?

@@AshishKumar-hm4fo As the video explains, Log-P refers to the octanol-water partition and so does not take pH into account. If the pH is accounted for, then it becomes Log-D If a Log-D value is given, the pH it's measured at should be quoted. Log-D for a given pH can be calculated from the Log-P and the pKa which is covered in the video from about 21 minutes. Many drugs have their Log-P and pKa listed (DrugBank website is a good source).

This one was good, and helpful, too.

By the fact we share a surname, I know Dermott is very mischievous and some of this comment is probably very much tongue in cheek (eg mumbo jumbo). But I'll attempt to answer. It's difficult to reply because I don't follow many of the points but to provide an answer. Hydrogen and helium and a smidgen of light elements were formed in the big bang. Heavier elements were formed in stars - up to iron, and then heavier than that in supernovae. It takes a lot of energy to squeeze nuclei together and so there is a limit to the atomic mass of the elements formed in this way. Moreover those very heavy isotopes have half-lives of fractions of a second. In the region of 258 isotopes are stable - they do not decay. All the elements with atomic numbers of 83 (bismuth) and above have no stable isotopes. Of the elements with atomic numbers lower than 83, only two, technetium (atomic number 43) and promethium (atomic number 61) have no stable isotopes. If you count all the radioactive isotopes with half-lives of a day or more then there are around 3500. And so yes, some of these isotopes are therefore extinct - they have decayed away into other lighter elements. As to "who decides" the answer is no one. Science does not work on an authority it is based upon the evidence. When the evidence builds beyond reasonable doubt it becomes the scientific consensus. In this case the mass of evidence was amassed for over 100-years. I have another video that might help with that concept th-cam.com/video/gHjvQmUekt4/w-d-xo.html

Happy to oblige :-)