Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8E) docx

... isocratic conditions for deter- mining the most suitable pH for the method. The retention behavior of active as a function of pH (isocratic) was determined. The best mobile-phase pH for further gradient ... can Π Π rL rL r r 2 30 2 46 30 46 0 425 . . . . . -i.d.column -i.d.column -i.d.column 2 -i.d.column 2 == METHOD DEVELOPMENT APPROACHES 425 be performed for further structural eluci...

Ngày tải lên: 15/12/2013, 12:15

... of analysis is critical to the success for fast and effective method development. The general approach for the method development for the separation of pharmaceutical compounds was discussed, ... SEPARATIONS Reversed-phase HPLC is the dominant method used for the majority of pharmaceutical applications (>95%). Normal-phase chromatography may be required for separations that...

Ngày tải lên: 24/12/2013, 18:15

... are three basic types of molecular forces: ionic forces, polar forces, and dispersive forces. Each specific technique capitalizes on each of these specific forces: 1. Polar forces are the dominant type ... employed in normal-phase HPLC (see Chapter 5). 2. Dispersive forces are employed in reversed-phase HPLC (see Chapter 4). 3. Ionic forces are employed in ion-exchange HPLC (see Chapter...

Ngày tải lên: 24/12/2013, 18:15

... in HPLC are porous particles with average diameters between 3 and 10µm. For most pharmaceutical applications, 3-µm particle sizes are recommended. Porosity provides the surface area necessary for ... predictability of retention and specificity for the separation of conformational isomers, and similar advantages are expected for these adsorbents in HPLC. 90 STATIONARY PHASES where...

Ngày tải lên: 24/12/2013, 18:15

... or microorganisms to screen their spectrum of 605 HPLC for Pharmaceutical Scientists, Edited by Yuri Kazakevich and Rosario LoBrutto Copyright © 2007 by John Wiley & Sons, Inc. 65. B. J. Druker, ... formic acid in acetonitrile and A was 0.2% formic acid in water; separation was performed at room temperature. importance and a key determinant in obtaining reliable pharmacokinetics...

Ngày tải lên: 22/01/2014, 00:20

... regulatory HPLC impurity profile, any HPLC method should be validated to some level to ensure acceptable accuracy and precision. 14.9.1 Prevalidation and System Suitability Prior to performing a formal ... prior to analysis by reversed-phase LC [21]. 14.4 HPLC DETECTORS The detectors utilized for HPLC are designed to respond to the solute being eluted. HPLC detectors can be classifi...

Ngày tải lên: 22/01/2014, 00:20

... the two sets of crystals, the molecules are 987 HPLC for Pharmaceutical Scientists, Edited by Yuri Kazakevich and Rosario LoBrutto Copyright © 2007 by John Wiley & Sons, Inc. which, by substitution ... different affinities for the enantiomers of another substance, then a single enantiomer of the latter will have different affinities for the enan- tiomers of the initial selector...

Ngày tải lên: 26/01/2014, 19:20

... 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

... 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