Binding to the railway track
This picture taken by my son, Ethan, at the Clementi Forest in Singapore shows a silhouette of a hiker with one leg binding to the deserted railway track.
Do you know that some drugs can bind preferentially to biological membrane of cells present in our body? These drugs are basic in nature and consequently they acquire positive charges at physiological pH of 7.4. Incidentally, the phospholipid bilayer of membrane (which resembles the railway track) acquires negative charges. As opposites attract, these positively charged drugs bind to negatively-charged biological membrane just like how the hiker is binding to the track!
As a recap, the apparent volume of distribution of drug, V, is an important pharmacokinetic parameter that informs the extent of drug distribution in our body. For basic drugs, their binding to tissues appears to correlate positively with increasing concentration of acidic phospholipids present in these tissues (how interesting)! This is undoubtedly a major contributor to the observation that basic drugs have V that are much larger than those of acidic drugs.
This is the fun fact for our today’s basic #pharmacokinetics #concept #10. Hope you enjoy the learning ??
If you like to learn more about the basic concepts in?#pharmacokinetics, let me know and follow my future posts.
DMPK scientist with special love for transporters, DILI and bile acids
6 个月Dear Prof Chan, I am a fan of your knowledge sharing platform and it helps me and lot of others. Just a thought (please correct me): for some of the acidic drugs for which are substrate of uptake transporters, their Vd can also be very high.