Title: Interlaboratory study of a NACE method for the determination of R-timolol content in S-timolol maleate: assessment of uncertainty
Authors: Marini, Roland Djang'eing'a ×
Groom, Carl
Doucet, François R
Hawari, Jalal
Bitar, Yaser
Holzgrabe, Ulrike
Gotti, Roberto
Schappler, Julie
Rudaz, Serge
Veuthey, Jean-Luc
Mol, Roelof
Somsen, Govert W
de Jong, Gerhardus J
Ha, Pham Thi Thanh
Zhang, Jie
Van Schepdael, Ann
Hoogmartens, Jos
Briône, Willy
Ceccato, Attilio
Boulanger, Bruno
Mangelings, Debby
Vander Heyden, Yvan
Van Ael, Willy
Jimidar, Ilias
Pedrini, Matteo
Servais, Anne-Catherine
Fillet, Marianne
Crommen, Jacques
Rozet, Eric
Hubert, Philippe #
Issue Date: Jun-2006
Series Title: Electrophoresis vol:27 issue:12 pages:2386-99
Abstract: Analyses of statistical variance were applied to evaluate the precision and practicality of a CD-based NACE assay for R-timolol after enantiomeric separation of R- and S-timolol. Data were collected in an interlaboratory study by 11 participating laboratories located in Europe and North America. General qualitative method performance was examined using suitability descriptors (i.e. resolution, selectivity, migration times and S/N), while precision was determined by quantification of variances in the determination of R-timolol at four different impurity levels in S-timolol maleate samples. The interlaboratory trials were designed in accordance with the ISO guideline 5725-2. This allowed estimating for each sample, the different variances, i.e. between-laboratory (s2(Laboratories)), between-day (s2(Days)) and between-replicate (s2(Replicates)). The variances of repeatability (s2r) and reproducibility (s2R) were then calculated. The estimated uncertainty, derived from the precision estimates, seems to be concentration-dependent above a given threshold. This example of R-timolol illustrates how a laboratory can evaluate uncertainty in general.
ISSN: 0173-0835
Publication status: published
KU Leuven publication type: IT
Appears in Collections:Pharmaceutical Analysis
× corresponding author
# (joint) last author

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