Carvedilol is an anti-hypertensive agent with nonselective β-blocking and α1-blocking activities.It has been widely used in the treatment of hypertension, myocardial infarction and congestive heart failure.However, the compound's low solubility and bypass first pass metabolism hinders its development.Recently nanocrystals has been developed as one of the most promising formulations for poorly water-soluble drugs.Accordingly, the aim of this work was to explore the particle size reduction effect of carvedilol on dissolution and absorption.