Objective: To design the proficiency testing (PT) project (No. NIFDC-PT-183) for assays of bismuth potassium citrate capsules and organize to assess the proficiency of complexometric titration in laboratories, and provide some technical analyses and advices.
Methods: Two groups of samples with different concentration were prepared. The uniformity was evaluated with one-way analysis of variance and the stability was confirmed with t-test, whose results all conformed the requirements. The samples with three combinations were randomly distributed to 279 laboratories. The determination was performed according to the assays of bismuth potassium citrate capsules in Volume Ⅱ of the Chinese Pharmacopoeia 2015. The median value and normalized interquartile range (NIQR) of robust statistical analysis was adopted and Z-scores were used to evaluate the results from each of laboratories.
Results: Among 279 laboratories, 240 laboratories results were satisfactory, 23 were questionable, and the other 16 were unsatisfied. The satisfaction rate was 86.0%.
Conclusion: The overall capacity of national laboratories for assays of bismuth potassium citrate capsules is good while a portion of participants require further improvement.

Objective To establish a method to qualitatively identify and quantitatively determine a new impurity from beclomethasone propionate inhalation aerasol.Methods Ultra-performance liquid chromatography-Q-exactive orbitrap-mass spectrometry(UPLC-QE-MS)technology and Discovery Studio software were used to identify and predict the toxicity of a new impurity in beclomethasone propionate inhalation aerasol,and the content of this new impurity was determined by UPLC.Results The new impurity in beclomethasone propionate inhalation aerasol was polybutylene terephthalate(PBT)cyclic dimer.Discovery Studio software predicted that PBT dimer had potential developmental toxicity,with no mutagenicity,no ocular and skin irritancy and no rodent carcinogenicity.The content range of PBT dimer in 9 batches of beclomethasone propionate inhalation aerasol was 20.5-116.6 pg per bottle.Conclusion This study can realize the rapid identification and toxicity prediction of the new impurity in the preparation,and provide a theoretical basis for the quality control of the preparation by determining their content.