Molecular Weight (MW)

The sum of the atomic masses of all atoms in a molecule, expressed in daltons (Da) or grams per mole (g/mol). Molecular weight is a key physicochemical property in drug design, as it influences oral absorption, membrane permeability, and metabolic susceptibility. Lipinski's Rule of Five recommends an upper limit of 500 Da for orally bioavailable small-molecule drugs.

Beispiele

• Aspirin: MW 180 Da (excellent oral absorption)
• Cyclosporine: MW 1,203 Da (violates Lipinski but absorbed via specialized formulations)
• Insulin glargine: MW ~6,063 Da (requires injection, too large for oral absorption)