USP-NF Stimuli Article on Apex Vessels used in Dissolution Testing

In the latest issue of the USP Pharmacopeial Forum, PF 51(1), a Stimuli article on the characterization of apex vessels has been published. The article written by Satish Perivilli and Mark R. Liddell is entitled "Characterization of Apex Vessel Geometries and Irregularities".

The dissolution test is a key test parameter routinely used for assessing the performance of solid and semi-solid dosage forms in both drug development and quality control. Apex vessels, previously known as PEAK vessels, are commonly used with USP Apparatus 2 in dissolution testing due to their potential to reduce coning, a common issue with standard vessels.

The study discussed in the new Stimuli articles aims to provide a comprehensive evaluation of apex vessels, focusing on their geometric features, variability between manufacturers, and implications for dissolution testing. It builds on previous work, such as the 2021 Stimuli article "The Case for Apex Vessels", and evaluates whether proposed specifications are suitable for current commercially available vessels.

The authors write that "a coordinate measuring machine (CMM) was used to evaluate 37 selected characterization parameters associated with the apex vessel geometries and inherent geometric irregularities. Six vessels, each from seven manufacturers, were characterized. Measurement data was analyzed using skewness plots and statistical tools to understand the variability in all parameters considered. Upon analysis, the apex characterization parameters were found to exhibit intra- and inter-manufacturer variability, indicating variability in the geometries of apex vessels available commercially. Measurements of the geometric irregularities associated with the apexes also presented similar variability across all vessels considered. Results from this study indicate that end-users of apex vessels should be aware of the variabilities in commercially available vessels and should consider controlling the source of apex vessels used with dissolution testing."

The Stimuli article is available after registration in the Pharmacopeial Forum. Stakeholders are encouraged to review and submit feedback. Comments are due to the USP by 31 March 2025.

Please note: On 17 January, the USP issued a Publication Correction. It says: "An incorrect version of Figure 6c (Skewness plot for axis-cylinder and -hemisphere perpendicularity) appeared in the article. [...] The Stimuli Article will be revised and republished in a future PF. "