Drug development recovery analysis

Agbaba et al. [56] developed an HPTLC method for the determination of omeprazole, pantoprazole, and their impurities omeprazole sulfone and N-methylpantoprazole in pharmaceutical. The mobile phase chloroform-2-propanol 25% ammonia-acetonitrile (10.8 1.2 0.3 4), enables good resolution of large excesses of the drugs from the possible impurities. Regression coefficients (r > 0.998), recovery (90.7-120.0%), and detection limit (0.025-0.05%) were validated and found to be satisfactory. The method is convenient for quantitative analysis and purity control of the compounds. 

Morrison, J.F., MacCrehan, W.A., Selavka, C.M., Evaluation of supercritical fluid extraction for the selective recovery of drugs of abuse from hair, 2nd International Meeting on Clinical and Forensic Aspects of Hair Analysis, National Institute on Drug Abuse. Special Publication, submitted, 1995. Welch, M.J., Sniegoski, L.T., Allgood, C.C., Habram M., Hair analysis for drugs of abuse evaluation of analytical methods, environmental issues, and development of reference materials, /. Anal. Toxicol, 17(6), 389-398, 1993. 

Direct HPLC enantioseparation techniques, which are free of many disadvantages of GC, indirect and chiral mobile phase HPLC methods, have gained unequivocal prevalence in bio-analytical studies. Several methods have been advanced so much that they allow enantiose-lective determination not only of the parent chiral drugs but also of their pharmacologically relevant metabolites [121]. As already mentioned above, a direct injection of biofluids offers several advantages in terms of analysis time and sample recovery. Precolumns packed with achiral or chiral packings, or with the recently developed so-called restricted-access packing materials, may be useful in this case. 

It can be assumed that with the development and study of new methods, the ability to determine M (S), the method bias component of uncertainty, cannot be done given that it can be evaluated only relative to a true measure of analyte concentration. This can be achieved by analysis of a certified reference material, which is usually uncommon, or by comparison to a well-characterized/accepted method, which is unlikely to exist for veterinary drug residues of recent interest. Given that method bias is typically corrected using matrix-matched calibration standards, internal standard or recovery spikes, it is considered that the use of these approaches provides correction for the systematic component of method bias. The random error would be considered part of the interlaboratory derived components of uncertainty. 

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