Experimental determination and computational prediction of blend time in the USP dissolution testing Apparatus 1

Abstract

The USP Apparatus 1 (rotating basket) is a preferred testing tool to evaluate the in vitro dissolution performance of pharmaceutical oral solid dosage forms, both as a quality control tool and to determine optimal drug formulations. The test relies on taking samples from the dissolution vessel during the dissolution process to obtain drug dissolution-time profiles. Of significant importance is the determination of the blend time, i.e., the time needed for the drug substance released from the dosage form to become dispersed throughout the vessel, especially at the sampling point. How representative these samples are with respect to the amount of drug dissolved can vary depending on operating and geometrical parameters. Here, the blend time in the USP Apparatus 1 was obtained experimentally and computationally for different operating conditions (basket mesh size, liquid fill volume, and rotation intensity) using the discoloration method coupled with image processing and by conducting time-dependent simulations using the Lattice-Boltzmann Large-Eddy Simulation approach. The experimental and predicted blend times were found to be in agreement. Additionally, an empirical correlation for blend time was developed. These results will help practitioners determine the effect of operating parameters on how representative the samples taken during the test are.