Simultaneous measurement of drug release and liquid uptake in pharmaceutical tablets.

A new method is introduced that allows drug release and liquid absorption to be studied simultaneously. The drug release is measured by the alternating ionic current (AIC) method, and the study of liquid uptake is accomplished with a sensitive microbalance from a processor tensiometer. We show that the method can be employed to study anomalous diffusion in the initial phase of the drug release process of disintegrating systems. We also demonstrate that the diffusion layer thickness and the diffusion coefficient in a dissolving system can be obtained with the new measurement technique.