Implementation of QbD Approach to the Development of Chromatographic Methods for the Determination of Complete Impurity Profile of Substance on the Preclinical and Clinical Step of Drug Discovery Studies

The purpose of this work was to demonstrate the use of the AQbD with the DOE approach to the methodical step-by-step development of a UHPLC method for the quantitative determination of the impurity profile of new CPL409116 substance (JAK/ROCK inhibitor) on the preclinical and clinical step of drug discovery studies. The critical method parameters (CMPs) have been tested extensively: the kind of stationary phase (8 different columns), pH of the aqueous mobile phase (2.6, 3.2, 4.0, 6.8), and start (20-25%) and stop (85-90%) percentage of organic mobile phase (ACN). The critical method attributes (CMAs) are the resolution between the peaks (>= 2.0) and peak symmetry of analytes (>= 0.8 and <= 1.8). In the screening step, the effects of different levels of CMPs on the CMAs were evaluated based on a full fractional design 2(2). The robustness tests were established from the knowledge space of the screening step and performed by application fractional factorial design 2((4-1)). Method operable design region (MODR) was generated. The probability of meeting the specifications for the CMAs was calculated by Monte-Carlo simulations. In relation to literature such a complete AQbD approach including screening, optimization, and validation steps for the development of a new method for the quantitative determination of the full profile of nine impurities of an innovative pharmaceutical substance with the structure-based pre-development pointed out the novelty of our work. The final working conditions were as follows: column Zorbax Eclipse Plus C18, aqueous mobile phase 10 mM +/- 1 mM aqueous solution of HCOOH, pH 2.6, 20% +/- 1% of ACN at the start and 85% +/- 1% of ACN at the end of the gradient, and column temperature 30 degrees C +/- 2 degrees C. The method was validated in compliance with ICH guideline Q2(R1). The optimized method is specified, linear, precise, and robust. LOQ is on the reporting threshold level of 0.05% and LOD at 0.02% for all impurities.