Solvent penetration rate in tablet measurement using video image processing.

We describe a simple technique for the measurement of solvent penetration rates into spray-dried lactose (DCL) tablets and tablets made of blended materials using digital video image processing. The results of the experimental study show that the penetration rate in some cases appears to be close to linear with time, which corresponds to non-Fickian or Case II-type diffusion. We discuss relevant capillary invasion models in order to explain the observed penetration rate. The proposed technique allows fast diffusion rate acquisition/processing and can be useful when designing immediate release tablets that require a large number of measurements corresponding to different formulations and processing parameters.