2009 Trends in Small-Volume Dissolution Apparatus for Low-Dose Compounds

The concept of small-volume dissolution arises from the need to determine the dissolution rate from low-dose,
generally high potency drugs or drugs with analytical techniques that are not very sensitive. Novel drug delivery
products including subcutaneous implants, ocular systems, microspheres, nanospheres, and combination products such
as drug-eluting stents (DES) have demanded more from traditional dissolution and drug-release apparatus. To maintain
quantitative levels of analyte during the dissolution test, a reduction in vessel volume accompanied by an alteration of
compendial dissolution apparatus may be required (1). The utilization of small-volume dissolution apparatus stems from
the need to provide accurate, reliable data for decision-making during drug development stages and assurance of quality
when the formulation reached full-scale production, as well as to maintain future assurance of product quality and
stability. This topic will explore the use and general limitations of typical compendial USP apparatus, noncompendial
modifications to the standard USP apparatus, and non-USP apparatus designed to yield small-volume dissolution
methods with reliable results. In addition, related issues concerning apparatus calibration, method development, and
method validation of the modified dissolution apparatus will be reviewed.