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

Validation of Robust Chromatography Methods Using Computer-Assisted Method Development for Quality Control, I.

Imre Molnár
LCGC, 9, 12, 800 (1996)


Initial experiments in high-performance liquid chromatographic method development I. Use of a starting gradient run

L.R. Snyder, J.W. Dolan
J. Chromatogr. A, 721, 1, 3–14 (1996), DOI: 10.1016/0021-9673(95)00770-9

Keywords: Method development, Gradient elution, Mobile-phase composition, Anxiolytics, Pesticides, Benzenes, Phenazines, Triazines, Polynuclear aromatic hydrocarbons

http://www.sciencedirect.com/science/article/pi...

A single gradient elution run with water (A) to acetonitrile (B) as mobile phase can be used to estimate preferred conditions for subsequent method development experiments based on RP-HPLC. For a broad range of sample types, that includes both very hydrophilic and hydrophobic compounds, it was found that isocratic retention is given by log k ≈ log kw −4.2ϕ, where ϕ = 0.01 %B. An initial gradient run allows values of log kw to be estimated for each compound in the sample, which then permits compound retention to be approximated as a function of either isocratic or gradient experimental conditions.

The use of an initial gradient run in this way provides a rational basis for the subsequent development of a final HPLC method. The present approach is based on a wide range of sample types and different reversed-phase columns; for this reason it is expected to be reasonably general and accurate. 


Initial experiments in high-performance liquid chromatographic method development II. Recommended approach and conditions for isocratic separation

J.A. Lewis, L.R. Snyder, J.W. Dolan
J. Chromatogr. A, 721, 1, 15–29 (1996), DOI: 10.1016/0021-9673(95)00771-7

Keywords: Method development, Isocratic elution, Mobile-phase composition, Nitroxylenes, Nitrotoluenes, Chloroanilines, Ethylanilines, Toluene, Benzyl cyanide, p-Cresol

http://www.sciencedirect.com/science/article/pi...

Initial method development experiments for both neutral and ionic samples are best carried out with reversed-phase high-performance liquid chromatography (HPLC) using acetonitrile-methanol-buffer mobile phases. The preceding paper (Part I) suggests the use of an acetonitrile-buffer gradient to start method development. In this paper, optimum conditions for this first separation are discussed. Sequential method development experiments plus computer simulations are then used to obtain a final HPLC method. In this connection, we have examined how many experiments are required for reliable predictions of ternary-solvent retention. Three experiments are sufficient to predict isoeluotropic retention for methanol-acetonitrile-buffer ternaries where solvent strength does not vary, but five experiments are required for ternaries that contain tetrahydrofuran.


New Approaches to HPLC Method Development

L.R. Snyder
Today's Chemist at Work, 5, 1, 29 (1996)


High-performance liquid chromatographic separation of the impurities in a pharmaceutical raw material with the aid of computer simulation

H.W. Bilke, I. Molnar, Ch. Gernet
J. Chromatogr. A, 729, (1), 189–195 (1996), DOI:10.1016/0021-9673(95)01185-4

Keywords: Pharmaceutical analysis, Computer simulation, Retention prediction

PDF

A complex pharmaceutical raw material was characterized by means of reversed-phase gradient elution. By varying gradient steepness and mobile-phase pH, it was possible to optimize band spacing so as to separate 16 impurities or degradation products from the drug substance. Computer simulation was useful in interpreting these complex chromatograms and determining the maximum number of peaks that could be separated in this way. A marginal separation of all 17 sample components could be obtained, but the resulting method was quite pH-sensitive and therefore not very rugged. As an alternative, a rugged method was developed that separates the drug substance from all other sample components. The present study also describes how present computer simulation software for isocratic separation can be used to predict resolution for gradient elution runs as a function of pH.


Optimization of additive compounds

DryLab-Team
DryLab 4 Example files (LC-Additive.dlproj) (1995)

Keywords: Coumarin, Potassium sorbate, Ascorbic acid, Sodium benzoate, vanillin, ethylvanillin, methylparaben, ethylparaben, sodium saccharin

Isocratic optimization of coumarin, potassium sorbate, ascorbic acid, sodium benzoate, vanillin, ethylvanillin, methylparaben, ethylparaben, sodium saccharin

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