Erlotinib vs Osimertinib

## Erlotinib vs Osimertinib: Overview

This comparison examines the pharmacological differences between **Erlotinib** and **Osimertinib**.

## Mechanism of Action

**Erlotinib**: Reversible inhibitor of EGFR (HER1) tyrosine kinase, blocking autophosphorylation.

**Osimertinib**: Third-generation irreversible EGFR TKI targeting T790M resistance mutation and activating mutations.

## Pharmacokinetics

**Half-life**: Erlotinib — 36 hours; Osimertinib — 48 hours.

## Chemical Properties

**Molecular Formula**: Erlotinib — C22H23N3O4; Osimertinib — C28H33N7O2.

**Molecular Weight**: Erlotinib — 393.4380 g/mol; Osimertinib — 499.6050 g/mol.

**Type**: Erlotinib — Small molecule; Osimertinib — Small molecule.