The objective and timing of drug disposition studies, appendix IV. Phenylbutazone formulations: in vitro dissolution and in vivo performance.

Human plasma level studies were conducted on various phenylbutazone formulations. The resultant data indicated that the nature of the formulation had a marked influence on the rate of phenylbutazone absorption. An in vitro dissolution rate apparatus was employed in an attempt to predict potential absorption of phenylbutazone from a given formulation. Based upon the in vitro-in vivo correlation, a new phenylbutazone tablet product was developed which produced a complete and more rapid absorption of the drug.