Exercise 2 was about finding a promising starting point for a method development by a literature search and subsequent ranking of the papers/methods. I must say that in general I was positively impressed by your work (in comparison to previous years). The citations were very good, you came up with concrete working conditions that made sense and you were able to state how sensitive you should be and how much sample you need. Average performance was 77%. What I liked is that all of you cited at least one of the meaningful papers and that so many also found the original, important papers from the eighties.
- 2 cases of obvious teamwork (minus 2 points for both), 2 cases of suspect teamwork.. please !
- Many of you cited a paper using derivative UV spectroscopy and one by Darwish which were used for dissolution testing. This is the wrong application and a technology you don’t necessarily have. This paper was therefore ranked lower than the ‘good’ ones: Matrix=plasma, analyte=tenoxicam, technology= HPLC/UV, paper=available and english
- One of you recommended using metabolites as internal standards. This is prohibited if you are analysing ex-vivo samples since the endogenous metabolite levels will mess up your quantification completely!!
|Task||Your answer/decision/comment||Evaluation, max. 22-23 points|
|Think about the task: Evaluate structure, how could it be done, can you estimate difficulty?||Aromatic system, weak acid, relatively high dose and good bioavailability = high concentrations are expected = HPLC-UV could be feasible but also LC/MS. Not difficult.||3 points = Comment on structure wrt detection, comment on application and dosage wrt sensitivity, answering the question|
|Develop a search phrase for finding references:||Determination of Tenoxicam in human plasma by HPLC with UV detection||1 point = mention of plasma, tenoxicam and quantification / detection / measurement|
|Searched in the following databases:||SciFinder||1 point per search|
|These are my 3 best papers (only examples!!)||Why|
|Mason JL, Hobbs GJ.: Simple method for the analysis of tenoxicam in human plasma using high-performance liquid chromatography. J Chromatogr B Biomed Sci Appl. 1995;665(2):410-415. doi:10.1016/0378-4347(94)00534-C||Very straightforward plasma precipitation. Aqueous solution is good for the RP chromatography. No mention of metabolite, LOQ 40ng/ml from 1ml||3 points for correct matrix, correct analyte, correct technology and accessible paper (e.g. not japanese..)|
|Heizmann P, Körner J, Zinapold K, et al.: Determination of tenoxicam in human plasma by high-performance liquid chromatography. J Chromatogr Biomed Appl. 1986;374(1):95-102. doi:10.1016/S0378-4347(00)83256-9||Liquid-liquid extraction will give a clean extract. Metabolite will be extracted along. LOQ 20ng/ml from 0.5ml||do. – 3 points|
|Madni MA, Raza A, Abbas S, et al. Determination of tenoxicam in the plasma by reverse phase HPLC method using single step extraction technique: a reliable and cost effective approach. Acta Pol Pharm. 2016;73(5):1129-1134.||Looks easy, |
corrected – is freely available. Looks good, peak shape and maybe sensitivity to be tested
|do. – |
|Amount of plasma||typically 0.25 – 1ml||1 point for concrete answer|
|Extraction method||liquid-liquid extraction or protein precipitation||1 point for concrete answer|
|HPLC column||reversed phase, typically C18||1 point for concrete answer|
|mobile phase||reversed phase, typically acetonitrile/phosphate buffer||1 point for concrete answer|
|Internal standard||typically||1 point for concrete answer|
|Detector setting||typically 350nm||1 point for concrete answer (wavelength)|
|Estimated sensitivity||around 50ng/ml||1 point for concrete answer (number)|