The incorporation of organic acids as pH-modifiers is a useful
technology to enhance the in vitro dissolution and in vivo bioavailability
of KZ, which is poorly water-soluble and has a
pH-dependent solubility profile. KZ–acid granules were successfully
prepared using conventional manufacturing technology
(high-shear granulation). Preparation of capsule and tablet formulation
is highly promising. Water-soluble acids were more effective
in enhancing dissolution than poorly water-soluble acids because
dissolution enhancement requires a rapid dissolution of acid in a
limited amount of water at the surface of granules. In addition,
the in vivo study using a rat improved the bioavailability independent
of gastrointestinal pH. Adding CA as pH-modifier has advantages
on improving dissolution rate as well as absorption rate. In
the pharmaceutical industry, improving absorption is a great challenge
in formulation development. Our investigation provides a
solution for improving absorption.