Initial evaluation of USP apparatus 4 for measuring dissolution profile of man-made vitreous fibers.

We report the successful evaluation of a US Pharmacopeia Apparatus 4 (USP-4) system in measuring the dissolution profiles of man-made vitreous fibers (MMVF)1. Glass and stone wool fibers with different (high- and low-) solubility profiles were tested in closed-loop configuration using a sodium/potassium phosphate buffer solution or an acetate buffer, respectively. Results confirm a need to operate in diluted conditions to avoid silicon saturation in the simulant solution and suppression of fiber dissolution. A clear fiber-to-fiber differentiation with good cell-to-cell reproducibility was achieved. These findings support the continued development of a USP-4 protocol for MMVF in vitro acellular testing.