Literature

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...

Keyword Year

Modeling of HPLC methods using QbD principles in HPLC

Imre Molnár, Hans-Jürgen Rieger, Robert Kormány
Advances in Chromatography, Eli Grushka, Nelu Grinberg , (CRC Press, Boca Raton, FL, 2016), 53, Chapter 8, 331–350

Keywords: Method Modeling, Mulitfactorial Modeling, Robustness Modeling, Modeling Protein Separations, Quality by Design, QbD, DryLab,

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http://doi.org/10.1201/9781315370385-9

HPLC method modeling is becoming a powerful tool to be used in the communication about method quality in HPLC between different labs, different companies, and between companies and regulatory agencies. The understanding of simple rules of peak movements will facilitate the development of new drugs, which are badly needed for smaller patient populations. The new features of HPLC modeling software, such as 3D resolution map, the modeled robustness testing, a practicable method transfer, or a method knowledge management offer a closed loop of all information about the birth and practical use of a method, and it further suggests the use of such software solutions in regulated laboratories to make analyst's life easier-especially in the pharmaceutical industry.

Modeling of HPLC methods using QbD principles in HPLC.


Method development for the separation of monoclonal antibody charge variants in cation exchange chromatography, Part I: Salt gradient approach

Sz.Fekete, A.Beck, J.Fekete, D.Guillarme
J Pharm Biomed Anal., 102, 33-44 (2015)

Keywords: Ion exchange, Salt gradient, Monoclonal antibody, Method development, Cetuximab

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http://doi.org/10.1016/j.jpba.2014.08.035

Ion exchange chromatography (IEX) is a historical technique widely used for the detailed characterization of therapeutic proteins and can be considered as a reference and powerful technique for the qualitative and quantitative evaluation of charge variants. When applying salt gradient IEX approach for mono-clonal antibodies (mAbs) characterization, this approach is described as time-consuming to develop and product-specific. The goal of this study was to tackle these two bottle-necks. The optimization was performed by computer simulation using DryLab modeling software and a custom made model.

By modeling the retention of several commercial mAbs and their variants in IEX, we proved that the mobile phase temperature was not relevant for tuning selectivity, while optimal salt gradient program can be easily found based on only two initial gradients of different slopes. Last but not least, the dependence of retention vs. pH being polynomial, three initial runs at different pH were required to optimize mobile phase pH. Finally, only 9 h of initial experiments were necessary to simultaneously optimize salt gradient profile and pH in IEX. The data can then be treated with commercial modeling software to find out the optimal conditions to be used, and accuracy of retention times prediction was excellent (less than 1% variation between predicted and experimental values).

Second, we also proved that generic IEX conditions can be applied for the characterization of mAbs possessing a wide range of pI, from 6.7 to 9.1. For this purpose, a strong cation exchange column has to be employed at a pH below 6 and using a proportion of NaCl up to 0.2 M. Under these conditions, all the mAbs were properly eluted from the column. Therefore, salt gradient CEX can be considered as a generic multi-product approach.


Method development for the separation of monoclonal antibody charge variants in cation exchange chromatography, Part II: pH gradient approach

Sz.Fekete, A.Beck, J.Fekete, D.Guillarme
J Pharm Biomed Anal., 102, 282-289 (2015)

Keywords: Ion exchange, Monoclonal antibody, pH gradient, Method development, Cetuximab

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http://doi.org/10.1016/j.jpba.2014.09.032

The cation exhange pH gradient approach was evaluated for the characterization of 10 model monoclonal antibodies including panitumumab, natalizumab, cetuximab, bevacizumab, trastuzumab, rituximab, palivizumab, adalimumab, denosumab and ofatumumab.

This work shows that retention and resolution can be modelled in cation exchange pH gradient mode, based on only four initial runs (i.e. two gradient times and two mobile phase temperature). Only 6 h were required for a complete method optimization when using a 100 mm × 4.6 mm strong cation exchange column. Optimization was performed by computer simulation using DryLab modeling software. The accuracy of predictions was excellent, with an average difference between predicted and experimental retention times of about 1%.

The 10 model antibodies were successfully eluted in both pH and salt gradient modes, proving that both modes of elution can be considered as multi-product charge sensitive separation methods. For most of the compounds, the variants were better resolved in the salt gradient mode and the peak capacities were also higher in the salt gradient approach. These observations confirm that pH gradient approach may be of lower interest than salt gradient cation exchange chromatography for antibody characterization.


Establishing column batch repeatability according to Quality by Design (QbD) principles using modeling software

Norbert Rácz, Róbert Kormány, Jenő Fekete, Imre Molnár
J Pharm Biomed Anal., 108, 10 April, 1–10 (2015), DOI: 10.1016/j.jpba.2015.01.037

Keywords: DOE, DryLab, QbD, Robustness, UPLC-column comparison

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Twelve columns of same brand name but different batches were compared. 3D design of experiment modeled by DryLab was used to compare column selectivity and performance. 3D resolution space allows establishing better method robustness before validation. A multivariable design space (MODR) allows flexible routine work with columns. This procedure allows easy column replacement to retain method robustness.


Multifactorial design principles applied for the simultaneous separation of local anesthetics using chromatography modeling software

C.Chamseddin, T.Jira
Anal. Methods, 6, 6702-6710 (2014)

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This study describes the development of liquid chromatographic methods for the simultaneous separation of some of the most popular local anesthetics in pharmaceutical preparations and medical praxis (benzocaine, bupivacaine, chloroprocaine lidocaine, oxybuprocaine, prilocaine, procaine, propipocaine and tetracaine) based on a systematic approach using experimental design methodology in which one or more factors are changed at the same time. The strategy employs a chromatography modeling software for the simultaneous optimization of critical chromatographic parameters, which are gradient time tG, temperature T and the ternary composition of the organic eluent B.

DryLab is one of the most established software for chromatography modeling, which allows for modeling of chromatographic separations based on input data from two or more experimental runs. The use of DryLab for HPLC modeling to facilitate methods development was well documented in the last 27 years. In this time a continuous development occurred to the software which enabled it to cope more with the ongoing technological progress. On the other hand, a number of published studies exist that deal with the use of DryLab in different chromatographic modes and wide application ranges. DryLab is applied to solve different analytical problems in pharmaceutical analysis, which deal mostly with the separation of active pharmaceutical ingredients (APIs) in the presence of their impurities and/or their degradation products. In the field of phytochemical analysis many applications on complex plant extracts are also available. Moreover, DryLab has been successfully applied to optimize the separation of different groups of environmental pollutants, peptides and proteins and metabolites.


Comparison of liquid chromatography and supercritical fluidchromatography coupled to compact single quadrupole massspectrometer for targeted in vitro metabolism assay

D.Spaggiari et. al
Journal of Chromatography A, 1371, 244–256 (2014)

Keywords: MS-supported automated method development, In vitro metabolism, Cocktail approach, UHPLC–MS, UHPSFC–MS, Compact single quadrupole

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http://dx.doi.org/10.1016/j.chroma.2014.10.055

Supercritical fluidchromatography (SFC) was for the first time applied in the context of an in vitro metabolism study. LC and SFC method development procedures were assisted with single quadrupole detector, optimization was performed by computer simulation using DryLab modeling software. Baseline separation of 16 compounds was achieved in both LC and SFC. LOQs of 2–100 ng/mL and 2–200 ng/mL were achieved in LC–MS and SFC–MS, respectively. The compact single quadrupole was successfully used for in vitro metabolism study.


DryLab® optimised two-dimensional high performance liquid chromatography for differentiation of ephedrine and pseudoephedrine based methamphetamine samples

Luke M. Andrighetto; Paul G. Stevenson; James R. Pearson; Luke C. Henderson; Xavier A. Conlan
Forensic Science International, 244, 302-305 (2014)

Keywords: DryLab, Multidimensional high performance liquid chromatography, Ephedrine, Pseudoephedrine, Methamphetamine

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http://dx.doi.org/10.1016/j.forsciint.2014.09.0...

In-silico optimised two-dimensional high performance liquid chromatographic (2D-HPLC) separations of a model methamphetamine seizure sample are described, where an excellentmatch between simulated and real separations was observed. DryLab optimisation reduced 2D-HPLC development time significantly. Targeted separation of model compounds was completed with significantly reduced method development time. This separation was completed in the heart-cutting mode of 2D-HPLC where C18 columns were used in both dimensions taking advantage of the selectivity difference of methanol and acetonitrile as the mobile phases. This method development protocol is most significant when optimising the separation of chemically similar chemical compounds as it eliminates potentially hours of trial and error injections to identify the optimised experimental conditions. After only four screening injections the gradient profile for both 2D-HPLC dimensions could be optimised via simulations, ensuring the baseline resolution of diastereomers (ephedrine and pseudoephedrine) in 9.7 min. Depending on which diastereomer is present the potential synthetic pathway can be categorised.

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