Literature

So far, more than 260 peer reviewed papers have been published on the application of DryLab – a complete list of which you can find here.

DryLab draws on the philosophy described in the three most famous Solvophobic Theory papers IIIIII of Csaba Horváth, which were developed in the years 1975-1977 at Yale University (see also literature by Dr. Imre Molnár).

Read more about the Fundamentals of DryLab and its History.

Keyword Year

Fast high performance liquid chromatography separations for proteomic applications using Fused-Core® silica particles

Stephanie A. Schuster, Barry E. Bo, Brian M. Wagner, Joseph J. Kirkland
J. Chromatography A, 1228, 232-41 (2012)

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http://doi.org/10.1016/j.chroma.2011.07.082

DryLab® was used with excellent results with superficially porous particles (Fused-Core®) which were designed with 160 Å pores. These particles show superior kinetics (lower resistance to mass transfer), allowing fast separations of peptides and small proteins (molecular weights of 15,000). The high efficiency and relatively low back pressure of these 2.7 μm Fused-Core particles has been maintained so that separations can be performed with conventional HPLC instruments.11 synthetic peptides (50 ng each) Fig. 12 show an excellent comparison of DryLab® predicted chromatogram to experimental ones. Chromatographic optimizations were conducted using DryLab® from the Molnár-Institute for Applied Chromatography. Longer columns can be used for higher resolution of complex mixtures of peptides, such as proteolytic digests. Highly reproducible separations of peptides at elevated temperatures with low pH mobile phases are maintained as a result of a stable bonded stationary phase. The utility of such highly stable materials is exemplified by separations of problematic amyloid peptides at low pH (TFA mobile phase) at an operational temperature of 100 °C.


Practical Application of Quality by Design Principles to The Development of an HPLC Assay Method for an API and Impurities

Kate E. Monks, Imre Molnár, Hans-Jürgen Rieger, F. Vogel
The Column, 8, 10, 2-9 (2012), http://www.chromatographyonline.com/practical-application-quality-design-principles-development-hplc-assay-method-api-and-impurities

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A method for the assay of an active pharmaceutical ingredient (API) and five known and unknown impurities was developed in accordance with Quality by Design (QbD) principles and using DryLab as a modeling software. Highly influential separation parameters were simultaneously and systematically studied so that the quality of the HPLC method could be understood, controlled and ensured. Consequently, during routine analysis out of specification (OOS) results can be corrected more effectively.


Analysis of recombinant monoclonal antibodies by RPLC: Toward a generic method development approach

Szabolcs Fekete, Serge Rudaz, Jenő Fekete, Davy Guillarme
J. Pharm. Biomed. Anal., 70, 158-68 (2012)

Keywords: Monoclonal antibodies, Core–shell, UHPLC, DryLab, Method development, Optimization software

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http://dx.doi.org/10.1016/j.jpba.2012.06.021

Monoclonal antibodies (mAbs) are an emerging class of therapeutic agents that have recently gained importance. To attain acceptable kinetic performance with mAbs in reversed phase liquid chromatography, there is a need to work with the latest generation of wide-pore sub-2 µm fully porous or core-shell particles stationary phases and the DryLab selectivity modeling software. In addition, temperature in the range 60-90 °C was found to be mandatory to limit adsorption phenomenon of mAbs and their fragments.  A generic method development strategy was proposed to account for the selectivity, efficiency, recovery, and the possible thermal Degradation using DryLab.  This study also demonstrated that the gradient steepness and temperature cannot be optimized using van't Hoff type linear models. Similarly, the common linear solvent strength model also generated some error in predicting the retention times. In contrast, when quadratic models were employed, the prediction accuracy of retention times was found to be excellent (relative error between 0.5 and 1%) using a reasonable number of experiments (9 or 6 experiments for optimization of gradient time and temperature, which requires between 6 and 8 h). Two separations of mAbs fragments were performed to demonstrate the reliability of the quadratic approach.


Baclofen ester and carbamate prodrug candidates: A simultaneous chromatographic assay, resolution optimized with DryLab®

Rasha Hanafi, Salwa Mosad, Khaled Abouzid, Raimund Nieß, Hilde Spahn-Langguth
Journal of Pharmaceutical and Biomedical Analysis, 56, 569–576 (2011)

Keywords: RP-HPLC, DryLab®, Baclofen, Prodrugs, Physicochemical properties

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http://dx.doi.org/10.1016/j.jpba.2011.06.023

Baclofen exhibits insufficient CNS-availability when dosed systemically. Hence, prodrug candi-

dates (methyl, ethyl, 1-propyl, 2-propyl and butyl 4-(tert-butoxycarbonyl amino)-3-(4-chlorophenyl)

butanoate) were synthesized aiming at CNS-levels appropriate for the treatment of spastic disorders.

The characterization of some biopharmaceutically highly relevant physicochemical properties (LogP

and aqueous solubility) and the evaluation of biophase levels represent one important component of

the project. The overall research aim was to generate an HPLC optimized method using DryLab®, a sim-

ulation software for the optimization of a RP-HPLC method, which was optimized using a simulation

software (DryLab®), for the simultaneous determination of baclofen and ten synthesized prodrug candidates. The chromatographic resolution predicted and obtained via the simulation is Rs >1.5 for all baclofen derivatives, as well as, with parent baclofen. The method was used to assay the prodrugs and determine their purities, solubility and lipophilicity parameters. The designed analytical method also permits the tracking of the new prodrug candidates' hydrolysis in vitro and in vivo. The determined physicochemical properties indicate for some of the compounds that they might be suitable for CNS-targeting which was exemplified by the detection of significant baclofen levels in rat brain tissues following an i.p. dose of ethyl carbamate (vs. ethyl ester, for which only traces of baclofen were detected).


Combined use of algorithms for peak picking, peak tracking and retention modelling to optimize the chromatographic conditions for liquid chromatography-mass spectrometry analysis of fluocinolone acetonide and its degradation products

M.J. Fredriksson, P. Petersson, B.-O. Axelsson, D. Bylund
Analytica Chimica Acta, 704 (1-2), 180-188 (2011)

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http://doi.org/10.1016/j.aca.2011.07.047

A strategy for rapid optimization of liquid chromatography column temperature and gradient shape is presented. The optimization as such is based on the well established retention and peak width models implemented in software like e.g. DryLab and LC simulator. The novel part of the strategy is a highly automated processing algorithm for detection and tracking of chromatographic peaks in noisy liquid chromatography-mass spectrometry (LC-MS) data. The strategy is presented and visualized by the optimization of the separation of two degradants present in ultraviolet (UV) exposed fluocinolone acetonide. It should be stressed, however, that it can be utilized for LC-MS analysis of any sample and application where several runs are conducted on the same sample. In the application presented, 30 components that were difficult or impossible to detect in the UV data could be automatically detected and tracked in the MS data by using the proposed strategy. The number of correctly tracked components was above 95%. Using the parameters from the reconstructed data sets to the model gave good agreement between predicted and observed retention times at optimal conditions. The area of the smallest tracked component was estimated to 0.08% compared to the main component, a level relevant for the characterization of impurities in the pharmaceutical industry.


Determination of stilbene derivatives in Burgundy red wines by ultra-high-pressure liquid chromatography

Agnes Fekete et. al
Analytical Bioanalytical Chemistry, 401 (5), 1517-25 (2011)

The polyphenols, for example stilbenes and flavonoids, are an important family of compounds present in grapes and wine. For the first time, eight natural stilbenes (trans-resveratrol, trans-piceid, cis-piceid, trans-astringin, trans-piceatannol, (+)-trans-Ɛ-viniferin, pallidol, and hopeaphenol), isolated and purified from Vitis vinifera, were simultaneously analysed by UHPLC coupled with photodiode-array detection. Separation of the stilbenes was optimized with the assistance of Quality-by-Design commercial software DryLab. Four different reversed-phase columns packed with 1.5-1.7 µm particles were tested and compared for their retention behaviour and separation efficiency. 

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