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

Renewal of an old European Pharmacopoeia method for Terazosin using modeling with mass spectrometric peak tracking

R. Kormány, I. Molnár, J. Fekete
J Pharm Biomed Anal., 135, 20 Februar, 8–15 (2017)

Keywords: Terazosin, Design of experiments, Quality by design, DryLab, HPLC, UHPLC, QDa detector, Method development, Method modeling

PDF
http://doi.org/10.1016/j.jpba.2016.11.050

An older method for terazosin was reworked in order to reduce the analysis time from 90 min (2 × 45 min) to below 5 min. The method in European Pharmacopoeia (Ph.Eur.) investigates the specified impurities separately. The reason of the different methods is that the retention of two impurities is not adequate in reversed phase, not even with 100% water. Therefore ion-pair-chromatography has to be applied and since that two impurities absorb at low UV-wavelength they had to be analyzed by different method than the other specified impurities. In our new method we could improve the retention with pH elevation using a new type of stationary phases available for high pH applications. Also a detection wavelength could be selected that is appropriate for the detection and quantification of all impurities.

The method development is the bottleneck of liquid chromatography even today, when more and more fast chromatographic systems are used. Expert knowledge with intelligent programs is available to reduce the time of method development and offer extra information about the robustness of the separation. Design of Experiments (DoE) for simultaneous optimization of gradient time (tG), temperature (T) and ternary eluent composition (tC) requires 12 experiments. A good alternative way to identify a certain peak in different chromatograms is the molecular mass of the compound, due to its high specificity. Liquid Chromatography–Mass Spectrometry (LC–MS) is now a routine technique and increasingly available in laboratories. In our experiment for the resolution- and retention modeling the DryLab4 method development software (Version 4.2) was used. In recent versions of the software the use of (m/z)-MS-data is possible along the UV-peak-area-tracking technology. The modelled and measured chromatograms showed excellent correlations. The average retention time deviations were ca. 0.5 s and there was no difference between the predicted and measured Rs,crit −values.


Optimization of non-linear gradient in hydrophobic interaction chromatography for the analytical characterization of antibody-drug conjugates

B. Bobály, G. M. Randazzo, S. Rudaz, D. Guillarme, Sz. Fekete
J. Chromatogr. A, 1481, 20 January, 82-91 (2017)

Keywords: Hydrophobic interaction chromatography, Antibody-drug-conjugate, Method development, Retention modeling, Non-linear gradient, DryLab, Method modeling

PDF
http://doi.org/10.1016/j.chroma.2016.12.047

The goal of this work was to evaluate the potential of non-linear gradients in hydrophobic interaction chromatography (HIC), to improve the separation between the different homologous species (drug-to-antibody, DAR) of commercial antibody-drug conjugates (ADC). The selectivities between Brentuximab Vedotin species were measured using three different gradient profiles, namely linear, power function based and logarithmic ones. The logarithmic gradient provides the most equidistant retention distribution for the DAR species and offers the best overall separation of cysteine linked ADC in HIC. Another important advantage of the logarithmic gradient, is its peak focusing effect for the DAR0 species, which is particularly useful to improve the quantitation limit of DAR0.

Finally, the logarithmic behavior of DAR species of ADC in HIC was modelled using two different approaches, based on i) the linear solvent strength theory (LSS) and two scouting linear gradients and ii) a new derived equation and two logarithmic scouting gradients. In both cases, the retention predictions were excellent and systematically below 3% compared to the experimental values.

 


Analysis of recombinant monoclonal antibodies in hydrophilic interaction chromatography: A generic method development approach

B. Bobály, V. D’Atri, A. Beck, D. Guillarme, Sz. Fekete
J Pharm Biomed Anal., 145, 25 October, 24-32 (2017)

Keywords: HILIC, Method development, Monoclonal antibody, Recovery, Dry Lab

PDF
http://doi.org/10.1016/j.jpba.2017.06.016

Hydrophilic interaction liquid chromatography (HILIC) is a well-established technique for the separation and analysis of small polar compounds. A recently introduced widepore stationary phase expanded HILIC applications to larger molecules, such as therapeutic proteins. In this paper, we present some generic HILIC conditions adapted for a wide range of FDA and EMA approved recombinant monoclonal antibody (mAb) species and for an antibody-drug conjugate (ADC). Seven approved mAbs possessing various isoelectric point (pI) and hydrophobicity as well as a cysteine conjugated ADC were used in this study. Samples were digested by IdeS enzyme and digests were further fragmented by chemical reduction. The resulting fragments were separated by HILIC. The main benefit of HILIC was the separation of polar variants (glycovariants) in a reasonable analysis time at the protein level, which is not feasible with other chromatographic modes. Three samples were selected and chromatographic conditions were further optimized to maximize resolution. A commercial software was used to build up retention models. Experimental and predicted chromatograms showed good agreement and the average error of retention time prediction was less than 2%. Recovery of various species and sample stability under the applied conditions were also discussed.


A workflow for column interchangeability in liquid chromatography using modeling software and quality-by-design principles.

R. Kormány, K. Tamás, D. Guillarme, Sz. Fekete
J Pharm Biomed Anal., 146, 30 November, 220-225 (2017)

Keywords: Column interchangeability, Design of experiments, DryLab, Method development, Quality by design, UHPLC

PDF
http://doi.org/10.1016/j.jpba.2017.08.032

Highlights:

  • We developed UHPLC method strategy for investigation of column interchangeability using modeling software.
  • The selected four stationary phases have some obvious differences in terms of surface area, coverage, carbon load and endcapping, but three of them could provide baseline separation in the same design space.
  • At the end, by using DryLab LC modeling software, it was found that two of the four columns share the same working point and are robust around this condition.
  • The predicted results were in good agreement with the experimental ones.

 


Quality by design approach: Regulatory need.

J. N. Sangshetti, M. Deshpande, Z. Zaheer, D. B. Shinde, R. Arote
Arabian Journal of Chemistry, Volume 10, Supplement 2, May, S3412-S3425 (2017)

Keywords: Quality by design (QbD), USFDA, Analytical techniques, Design of experiment, Risk assessment

PDF
http://doi.org/10.1016/j.arabjc.2014.01.025

Abstract

In this era of competition quality has been given prime magnitude; failure to meet such quality allied goals produces massive shift of company in share of market. In this context pharmaceutical industry is utmost regulated industry as it is governed by authoritative regulatory bodies. “Quality could be planned and most of quality deficit arises in the way process is planned and developed”, this thought of well known quality expert Joseph Moses Juran gives foundation to the concept of quality by design (QbD). USFDA launched a pilot programme in 2005 to permit participating firms a prospect to submit chemistry, manufacturing, and controls (CMC) of NDA information representing application of QbD. Now USFDA is accelerating QbD drive by making warning to generic manufacturers from January 2013. QbD has its perspectives to contribute the drug design, development, and manufacture of high-quality drug products. In the present review basic consideration of the QbD approach, its historical background, and regulatory needs are discussed. In detail explanation of elements of QbD i.e. method intent, design of experiment, and risk assessment is given. Application of QbD to pharmaceutical and biopharmaceutical processes, development and unit operation associated with it are briefly mentioned. Detail account of QbD to analytical technique is explained thoroughly by referencing examples. Commerially available chromatography optimization software, DryLab was used to perform computer simulations.


Current challenges and future prospects in chromatographic method development for pharmaceutical research

F. T. Mattrey et. al
J Pharm Biomed Anal., 95, October, 36-46 (2017)

Keywords: Liquid chromatography, Supercritical fluid chromatography, Method development workflow, Method screening, Analytical method modeling, Quality-by-design, Allotrope Foundation, Pharmaceutical analysis

PDF
http://doi.org/10.1016/j.trac.2017.07.021

Highlights:

  • New trends in chromatographic method development.
  • Recent developments in chromatographic screening, modeling and knowledge management.
  • Evolution of strategies for pharmaceutical method development in SFC and HPLC.
  • DryLab was the first software for the modeling and simulation of reversed phase HPLC separations.
  • The future outlook for improved method development algorithms and intelligent systems.
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