modern HPLC for practicing scientists

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 7A) pptx

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 7A) pptx
... techniques, principally in the form of high-performance liquid chromatography (HPLC) / MS (LC/MS), mass spectrometry has become the principal method of mixture analysis in pharmaceutical research and ... ions Clearly, the ion formation process is separated from solvent evaporation process in APCI (in contrast to ESI), allowing the use of solvents unfavorable for ion formation For example, 290 APPLICATIONS ... of the most widely used systems for analysis of large biomolecules For a continuous ion source, the ions can be stored for a short period of time and pulsed out for analysis In the case of ESI,...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 7B) pptx

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 7B) pptx
... 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 ... was achieved for the exact mass measurements, using PEG sulfates as internal calibration substance Based on the high-resolution MS information, empirical formulae were obtained for all components ... might be the intermediates for formation of the keto acid, were also observed in the radiochromatogram of rat plasma (spectrum not shown) [131] Scheme 11 Mechanism for the formation of metabolite...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8A) ppt

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8A) ppt
... sometimes the ACD prediction of the solubility 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 excipients ... ACD prediction versus HPLC experimental results for the solubility of a basic compound for these studies Fast gradient methods on short columns are usually used in most cases for solubility determination ... different solutions prepared at the different pH values For example, in Figure 8-7 if the target concentration for the HPLC assay is mg/mL for this basic compound, then the sample at pH (8 mg/mL...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8B) pdf

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8B) pdf
... 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 ... respective analytical method that is applied to a real in-process sample or a dosage form for subsequent HPLC analysis The analytical procedure must specify the manufacturer, type of filter, and ... Stationary Phase Ideally for a reversed-phase separations, the retention factors (k) for all components in a sample should lie between and 10 to achieve separation in a reasonable time For a given stationary...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8C) pdf

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8C) pdf
... peak height) for peak B ≤ 1.5 Tailing factor (5% peak height) for peak A ≤ 1.5 Rt for peak A must be 12.0 ± 1.3 Rt for peak B must be 21 ± 1.0 The S/N of the LOQ solution (0.05%) for both actives ... acetonitrile The experiments for w pH 2–4 were performed on day w 1, and those for w pH 5–7 were performed on day (≈36 hr after initial prepaw ration) A further investigation was performed by preparing ... chromatographer down the right path for initial mobilephase pH selection In the following case study for this pharmaceutical compound M, the method development scenario and rationale for each iteration in...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8D) pdf

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8D) pdf
... analyte pKa shift) for both basic ionization centers Therefore this cors relates with a spKa of 2.7 for pyridinal nitrogen (i.e., 3.3 − 0.6 = 2.7) and with s a spKa of 4.7 for the morpholinal ... is in its neutral form No lower METHOD DEVELOPMENT APPROACHES 411 limit plateau is observed where the analyte would be in its fully ionized form Therefore, further analysis for this compound ... molecule in its neutral form The pKa shift of the ionizable analyte For this example, since the analyte is basic, the downward pKa shift for basic analytes must be accounted for The working pH should...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8E) docx

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8E) docx
... isocratic conditions for determining 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 ... AMDS/Dry Lab for method optimization and then use MS to confirm the separation of active species from possible co-eluting species MS/MS analysis can 426 METHOD DEVELOPMENT be performed for further ... Drylab, a forced degradation sample was run that was stressed at 50°C for week in pH diluent It was noted that a major impurity was formed (Figure 8-49) and was determined to be the carboxylic acid...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8F) docx

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 8F) docx
... NORMAL-PHASE 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 are not compatible ... crystals that will damage the seal over time Therefore it is recommended to wash the HPLC system with acetonitrile/water (20 : 80) for at least 30 before the system is shut down to remove any potential ... 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,...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 1) docx

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 1) docx
... three basic types of molecular forces: ionic forces, polar forces, and dispersive forces Each specific technique capitalizes on each of these specific forces: Polar forces are the dominant type of ... normal-phase HPLC (see Chapter 5) Dispersive forces are employed in reversed-phase HPLC (see Chapter 4) Ionic forces are employed in ion-exchange HPLC (see Chapter 4, Section 4.10) The fourth type of HPLC ... performed to adequately control and monitor the quality of the prospective drug candidates, excipients, and final products Effective and fast method development is of HPLC for Pharmaceutical Scientists, ...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 2) pptx

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 2) pptx
... ( c s ) = K H K p ce (2-66) 56 HPLC THEORY where KH is a Henry adsorption constant The final form of the distribution function, accounting for v0 = vm + vs, therefore will be ψ (ce ) = [v0 + ( ... 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 in the form ...  (a − 1)  k1 +  (2- 22) For closely eluted peaks and relatively high efficiency of the system, these assumptions not lead to the significant deviations of equation (2- 22) from true resolution...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 3) docx

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 3) docx
... in HPLC are porous particles with average diameters between and 10 µm For most pharmaceutical applications, 3-µm particle sizes are recommended Porosity provides the surface area necessary for ... compounds) could play a major role All these factors are the driving force for the search in alternative base materials for HPLC packings 90 STATIONARY PHASES The majority of polymer-based packing ... predictability of retention and specificity for the separation of conformational isomers, and similar advantages are expected for these adsorbents in HPLC SURFACE OF CHEMICALLY MODIFIED MATERIAL...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 4A) ppt

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 4A) ppt
... have different selectivity for components in a sample, as can be seen for a forced degradation sample analyzed on three different types of reversed- STATIONARY PHASES FOR RPLC 143 phase columns ... 3.0 mm; particle sizes, 3.5 µm for Symmetry Shield and Atlantis and 3.0 µm for YMC ODS AQ (Courtesy of Markus Krummen, Novartis Pharmaceuticals.) 144 REVERSED-PHASE HPLC the alkylsilane phases [17–21] ... base Equilibrium constants for acids can be written in the following form: Ka = [ A − ] ⋅[ H + ] [ AH ] (4-10) Using the definition for the pH (Hendersen–Hasselbalch form), one can rewrite  [AH]...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 4B) pdf

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 4B) pdf
... of pKa for the target analyte and related impurities is particularly useful for commencement of method development of HPLC methods for key raw materials, reaction monitoring, and active pharmaceutical ... are the limiting factors s for the fully ionized and neutral forms of the analyte The inflection point of 184 REVERSED-PHASE HPLC s Figure 4-32 Retention versus spH for aniline from 10 to 50 v/v% ... Similar parameters have been determined for this family of compounds for methanol/water mixtures [80] Using these parameters for each family of compounds for a particular type of organic, the as...
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Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 4C) pdf

Tài liệu HPLC for Pharmaceutical Scientists 2007 (Part 4C) pdf
... the Pharmaceutical Industry Since a great majority of drugs include basic functional groups, HPLC behavior of basic compounds has attracted significant interest [183] Therefore, reversed-phase HPLC ... retention of very polar basic species is also very important for pharmaceutical applications For example, Voglibose (VGB) is very hydrophilic; therefore in RPLC even under high aqueous conditions using ... the RP HPLC We hope that it will be useful for practical chromatographers in their efforts to develop efficient and selective separation methods, and we also hope that it will be encouraging for...
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