Master the Pharmaceutics Drug Distribution Challenge 2026 – Navigate Your Path to Success!

A high volume of distribution means the drug moves beyond the plasma and into tissues. Lipophilic drugs partition into lipid-rich tissues and cross cell membranes readily, so they accumulate in tissues rather than staying in the blood. This extensive tissue distribution drives a large Vd. In contrast, hydrophilic, polar, or ionized molecules don’t cross membranes as easily and remain mainly in plasma or extracellular fluid, leading to a smaller Vd. So lipophilicity best explains a high Vd.