Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 2) pptx

... interest [42, 43]. In HPLC these compounds are used as mobile-phase additives for the enhancement of basic analyte reten- 62 HPLC THEORY Figure 2-18. So-called van’ t Hoff plot for the retention ... nonionic form of the analyte at conditions where protonation is completely suppressed. Corresponding capacity factors for neutral and protonated forms of basic analyte could be written i...

Ngày tải lên: 24/12/2013, 18:15

... ions on the basis of mass-to-charge ratios, 281 HPLC for Pharmaceutical Scientists, Edited by Yuri Kazakevich and Rosario LoBrutto Copyright © 2007 by John Wiley & Sons, Inc. 150°C, depending ... flow to about 400°C for over 50 µL/min of solvent flow. For LC/APCI-MS, the APCI probe temperature is normally set at 400°C, which can be higher for involatile samples or lower for...

Ngày tải lên: 15/12/2013, 12:15

... metabolites are important biotransformation pathways for many drugs and xenobiotics [127, 132, 133]. For example, the formation of acyl glucuronide conjugate forced the withdrawal of four marketed ... intermediates for formation of the keto acid, were also observed in the radiochromatogram of rat plasma (spectrum not shown) [131]. PRACTICAL APPLICATIONS 335 Scheme 11. Mechanism for th...

Ngày tải lên: 15/12/2013, 12:15

... based on the forced transport of the polymer molecules through the porous stationary-phase media under the conditions of suppressed interactions of the 263 HPLC for Pharmaceutical Scientists, ... in reversed-phase chromatography applications for example, if the area% does not agree with the assay% value for pharmaceutical analysis of a particular active pharmaceutical ingredient...

Ngày tải lên: 24/12/2013, 18:15

... appropriate validated methods. 455 HPLC for Pharmaceutical Scientists, Edited by Yuri Kazakevich and Rosario LoBrutto Copyright © 2007 by John Wiley & Sons, Inc. By performing these two experiments ... (e.g., for optically active substances, in addition to an achiral HPLC method, a chiral HPLC method may be added). Identity is a general requirement for dosage forms. When...

Ngày tải lên: 24/12/2013, 18:15

... the type of dosage form (tablets versus capsules) and the respective storage conditions for each of the dosage forms. 15.6 TEST METHODS FOR MOST COMMON DOSAGE FORMS IN WHICH HPLC IS THE PRIMARY ... and stability testing Identification [HPLC, UV, IR, NIR] (for release only) Assay [HPLC, NIR, CE, GC] Degradation products [HPLC, CE] 686 ROLE OF HPLC DURING FORMULATION DEVELOPMENT TABLE 1...

Ngày tải lên: 22/01/2014, 00:20

... cells. It not only interferes with foreign invaders that may cause infections, but also prevents the growth and spread of other diseased 837 HPLC for Pharmaceutical Scientists, Edited by Yuri Kazakevich ... (17+,18+, 19+,20+) for the reduced form, indicating a more open form of protein struc- ture for protonations upon disulfide-bonds reduction. Furthermore, the mol- ecular weight i...

Ngày tải lên: 22/01/2014, 00:20

... the ACD prediction of the solubil- ity for the ionized form of bases and acids shows greater deviation than for the solubility predicted for the neutral form of the molecules. Reaction of the ... during method development; these include speed 347 HPLC for Pharmaceutical Scientists, Edited by Yuri Kazakevich and Rosario LoBrutto Copyright © 2007 by John Wiley & Sons, Inc. ....

Ngày tải lên: 15/12/2013, 12:15

... by the pressure limitation of the HPLC equipment. For more information on gradient separation and developing fast HPLC methods, see Chapter 17 and Practical HPLC Method Development from Synder ... chromatographic selectivity for a set of compounds, bonded phase stability, and lot-to-lot reproducibility). The criteria for selec- tion may include that the column is stable for a ce...

Ngày tải lên: 15/12/2013, 12:15

... The experiments for w w pH 2–4 were performed on day 1, and those for w w pH 5–7 were performed on day 2 (≈36 hr after initial prepa- ration).A further investigation was performed by preparing ... down the right path for initial mobile- phase pH selection. In the following case study for this pharmaceutical compound M, the method development scenario and rationale for each itera...

Ngày tải lên: 15/12/2013, 12:15