Literature

So far, more than 270 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

Rapid UHPLC Method Development for Omeprazole Analysis in a Quality-by-Design Framework and Transfer to HPLC Using Chromatographic Modeling

A. Schmidt, M. Stanic
LCGC North America, 32, 2, 126-148 (2014)

Keywords: UHPLC, DryLab, QbD, Design Space, Method Development, Method Modeling, Method Transfer, Omeprazole, Impurities

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The aim of this study was to apply quality-by-design principles to build in a more scientific and risk-based multifactorial strategy in the development of an ultrahigh-pressure liquid chromatography (UHPLC) method for omeprazole and its related impurities.

The work presents a quality-by-design–based method development strategy for a method that tests the purity of omeprazole. The scientific and risk-based multifactorial method development strategy uses visual chro- matographic modeling as a fast and easy-to-use development tool. To speed up the method development process, all experiments are performed on a UHPLC system. The final method is successfully transferred to HPLC conditions. Predicted and experimental retention times are verified to confirm accuracy of the model.


UHPLC Method Development and Modelling in the Framework of Quality by Design

I. Molnár, H.-J. Rieger, A. Schmidt, J. Fekete, R. Kormány
The Column, 10, 6, 16-21 (2014)

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http://www.chromatographyonline.com/view/uhplc-...

The goals in ultrahigh-pressure liquid chromatography (UHPLC) method development are to first find the best separation, second find the best column, and third find the most robust method in a multifactorial Design Space. Trial and error methods are not sufficient anymore and solid science based on Quality by Design (QbD) principles is required.


Reliability of simulated robustness testing in fast liquid chromatography, using state-of-the-art column technology, instrumentation and modelling software

R. Kormány, J. Fekete, D. Guillarme, Sz. Fekete
Journal of Pharmaceutical and Biomedical Analysis, 89, 67-75 (2014)

Keywords: Robustness, UHPLC, DryLab, Method development, Modeling software, Column interchangeability

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http://dx.doi.org/10.1016/j.jpba.2013.10.029

The goal of this study was to evaluate the accuracy of simulated robustness testing using commercial mod- elling software (DryLab) and state-of-the-art stationary phases. For this purpose, a mixture of amlodipine and its seven related impurities was analyzed on short narrow bore columns (50 × 2.1 mm, packed with sub-2  m particles) providing short analysis times. The performance of commercial modelling software for robustness testing was systematically compared to experimental measurements and DoE based pre- dictions. We have demonstrated that the reliability of predictions was good, since the predicted retention times and resolutions were in good agreement with the experimental ones at the edges of the design space. In average, the retention time relative errors were <1.0%, while the predicted critical resolution errors were comprised between 6.9 and 17.2%. Because the simulated robustness testing requires signif- icantly less experimental work than the DoE based predictions, we think that robustness could now be investigated in the early stage of method development.

Moreover, the column interchangeability, which is also an important part of robustness testing, was investigated considering five different C8 and C18 columns packed with sub-2  m particles. Again, thanks to modelling software, we proved that the separation was feasible on all columns within the same analysis time (less than 4 min), by proper adjustments of variables.


Reliability of computer-assisted method transfer between several column dimensions packed with 1.3–5 µm core–shell particles and between various instruments

R. Kormány, J. Fekete, D. Guillarme, Sz. Fekete
Journal of Pharmaceutical and Biomedical Analysis, 94, 188–195 (2014)

Keywords: Method transfer, Method development, DryLab, Modeling software, Core–shell particles

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http://dx.doi.org/10.1016/j.jpba.2014.01.037

In this contribution, the possibility to automatically transfer RPLC methods between different column dimensions and instruments was evaluated using commercial modelling software. The method transfer reliability was tested with loratadine and its 7 related pharmacopeial impurities. In this study, state- of-the-art columns packed with superficially porous particles of 5, 2.6, 1.7 and 1.3 µm particles were exclusively employed. A fast baseline separation of loratadine and related impurities (Rs,min = 2.49) was achieved under the best analytical conditions (i.e. column of 50 mm × 2.1 mm, 1.3 µm, 10–90% ACN in 5 min, T = 40 ◦ C, pH = 3, F = 0.5 ml/min). This optimal method was successfully tested on columns packed with other particle sizes, namely 1.7 and 2.6 µm, to reduce pressure drop. The selectivities and retentions remained identical, while the peak widths were logically wider, leading to a reduction of peak capacity from 203 to 181 and 159 on the 1.3, 1.7 and 2.6 µm particles, respectively. On the minimum, the reso- lution was equal to 1.54 on the 50 mm × 2.1 mm, 2.6 µm stationary phase. Next to this, the method was transferred to columns of different lengths, inner diameters and particle sizes (100 mm × 3 mm, 2.6 m or 150 mm × 4.6 mm, 5 µm). These columns were used on other LC instruments possessing larger dwell volumes. The modelling software employed for developing the original method was able to calculate the new gradient conditions to be used. The accuracy of prediction was excellent, as the average retention time errors between predicted and observed chromatograms were −0.11% and 0.45% when transferring the method to 100 mm × 3 mm and 150 mm × 4.6 mm columns, respectively. This work proves the use- fulness and validity of HPLC modelling software for transferring methods between different instruments, column dimensions and/or flow rates. 
 


Quality by Design in Pharmaceutical Analysis Using Computer Simulation with UHPLC

R. Kormány, I. Molnár, J. Fekete
LCGC North America, 32, 5, 354–363 (2014)

http://www.chromatographyonline.com/view/qualit...

In this study, the quality-by-design principle is applied instead of trial-and-error in the development of a liquid chromatography method. With few measurements, the appropriate stationary phase and chromatographic conditions such as the composition of mobile phase, gradient time, temperature, and pH can be determined. A mixture of an active pharmaceutical ingredient and its 13 impurities was analyzed on a short narrow-bore column (50 mm × 2.1 mm, packed with sub-2-µm particles) providing short analysis times. The performance of commercial modeling software for robustness testing was systematically compared to experimental measurements and design-of-experiment–based predictions.


In silico robustness testing of a compendial HPLC purity method by using of a multidimensional design space build by chromatography modeling — Case study pramipexole

A. H. Schmidt, M. Stanic, I. Molnár
J. Pharm. Biomed. Anal., 91, 97-107 (2014)

Keywords: HPLC method development, Quality by Design, Design Space, Robustness in routine quality control, Pramipexole

PDF
http://dx.doi.org/10.1016/j.jpba.2013.12.023

Highlights:

  • Innovative QbD-based approach for robustness testing of a compendial HPLC method.
  • A Design Space was constructed to study the robustness in silico.
  • Required peak resolution of 2.0 could not be reached in all experiments.
  • After adjusting the gradient time the requirements were fulfilled.
  • A separate “Eluent Design Space” study was performed.

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