The main objective in all optimization procedures is to define the most appropriate conditions for rapid, sensitive, precise, and reproducible analysis, as economically as possible. Experimental design and DryLab optimization software have been used to optimize a liquid chromatographic method for separation of lercanidipine and its three impurities. In both methods of optimization the acetonitrile content and pH of the mobile phase were factors extracted for analysis, resolution of a critical pair was output in both cases. Data obtained from both optimization methods were compared and appropriate conclusions were extracted with the objective of gaining a complete view of chromatographic behavior. Detailed description was obtained by use of a three-dimensional graph and DryLab maps.

A stepwise method development strategy was employed in developing a robust HPLC method to resolve several closely eluting process impurities associated with a novel diabetes compound. The strategy consisted of rapid column screening, optimization of mobile phase compositions and separation temperature, DryLab modelling, and experimental verification of optimized separation conditions. The column evaluation process involved screening of a series of 20 columns varying in bonding chemistry using four sets of mobile phases composed of water, ACN and/or MeOH at three different pH’s. The screening process resulted in identifying two promising columns: XBridge Shield RP18 and SunFire C18. The effects of organic modifiers and separation temperatures were then evaluated to narrow down the chromatographic separation parameters. DryLab® was used to predict optimized gradient profile and separation temperature. Finally, the DryLab® predictions were verified experimentally. The study demonstrates that factors such as stationary phase composition, organic modifiers, pH and separation temperature have profound and often complex effects on chromatographic conditions. Therefore, it is critical to adopt a rational strategy as demonstrated here to evaluate the interplay of these factors, there by greatly enhancing method development efficiency.

The development of gradient methods in HPLC is a difficult task. The transfer of the methods requires deep understanding the process in the column and the factors, which are required for a safe operation in the routine lab. The talk will discuss the aspects, how to make reliable methods using computerized design in the development.

This paper describes a strategy for the development of chromatographic methods for drug candidates based upon the use of simple MS-compatible mobile phases and optimization of the chromatographic selectivity through variations of the stationary phase and mobile phase pH. The strategy employs an automated column selection system and a series of HPLC columns, varying in hydrophobicity and silanol activity, in combination with DryLab software to develop chromatographic methods for the separation of mixtures of bupivacaine and its metabolites, acidic, basic, and neutral compounds, and atenolol, nitrendipine, and their degradation products.

An optimization strategy for ternary solvent-strength gradient elution RP chromatography is described in which a 2-dimensional model of gradient time (2 levels) against ternary proportions of organic modifiers (4 levels) was constructed. Modelling was performed using Drylab. From the resolution surface the optimum ratio of organic modifiers could be selected. Excellent retention time and acceptable peak width and resolution simulations were obtained. The separation could be further optimized from the same input data by using a standard one-dimensional model in order to optimize for gradient slope, duration and shape. Excellent retention time and acceptable peak width and resolution simulations were obtained (< 1, 2 and 6% error respectively).