A certified commercially prepared product (Seronorm Trace Elements; Sero AS, Billingstads, Norway) was used to determine the intra-batch accuracy and ensure inter-batch standardization.
Analysts/chemists in TCHM R&D laboratories and TCHM manufacturing industries who are involved in extraction and formulation of herbal products need to upgrade their skills on HPLC for batch-to-batch identification and standardization protocols.
In the full study population, after standardization between batches and exclusion of 1% outliers of 5-mdC distribution, 5-mdC levels were normally distributed in both cases (n = 176) and controls (n = 173) assessed by skew and kurtosis test.
Particle-free 0- and 4-hr antioxidant controls, as well as 4-hr positive (residual oil fly ash) and negative (carbon black) particle controls, were run in parallel to quantify autooxidative losses and permit standardization between batches of samples.
There were spots clearly observed in all three batches, and Rf values were calculated for standardization parameters in each batch (Fig. 1).
16 Studies by groups in India and Brazil reported significant differences in osmolarity and oxidation states between batches 17, 18 emphasising the need for standardization and monitoring product stability by the drug manufacturers.
Using allergen extracts for allergy diagnosis and therapy is associated with problems in extract standardization and often incontrollable batch-to-batch variability [27], [28].
However, as a natural material, it suffers from variability between batches that can complicate the standardization of culture conditions.
All tests were performed by the same operator and by using plates with a same batch number in order to optimize standardization of the analysis.
Other commonly used batch effect methods include mean centering, standardization, and ratio-based methods [ 7].
In globalization, standardization — and higher standards.
