Effect of formulation and process variables on bioequivalency of nitrofurantoin II: in vivo-in vitro correlation

Based on preliminary in vitro evaluation, six formulations presenting a broad range of dissolution rates were selected for bioequivalency determination in a randomized complete block crossover. In vitro-in vivo correlations were developed relating cumulative percent dissolved to cumulative percent excreted. These correlations appear to be useful for comparing different formulations as well as different batches of the same formulation.