A drug with a volume of distribution (Vd) greater than 1 is typically categorized as?

A drug with a volume of distribution (Vd) greater than 1 is typically categorized as lipophilic. The volume of distribution is a pharmacokinetic parameter that describes how extensively a drug is distributed throughout the body's tissues compared to the plasma.

When a drug is lipophilic, it has a higher affinity for fat and tissues rather than remaining in the bloodstream. This means that lipophilic drugs tend to distribute widely throughout the body's fat tissues, leading to a high volume of distribution. A Vd greater than 1 indicates that the drug is not just confined to the vascular compartment but is instead accumulating in various tissues, often due to its lipid-soluble nature.

In contrast, hydrophilic and polar drugs usually have a lower volume of distribution because they tend to remain in the aqueous compartments of the body, such as blood and extracellular fluid, rather than entering fatty tissues. Hence, their Vd would generally be less than 1. Understanding these properties is crucial for predicting drug behavior in the body, including absorption, distribution, metabolism, and excretion.