Recent application of analytical methods to phase I and phase II drugs development: a review.

Drug development is a time-consuming and costly process. It is usually divided into four phases, although it is not always possible to draw a sharp line between the various stages. In phase I and II there are many molecules investigate and it is necessary to analyze all of them in a short period of time, with lower costs, and with high-throughput assay. During phase I relevant chemical-physical parameters like the acid dissociation constant, lipophilicity, solubility and stability must be analyzed. Classic techniques such as 'shake-flask' can be used, but instrumental analytical methods such as HPLC may be helpful to improve and enhance the productivity and reproducibility of the results. During phase II the activity of a drug and factors that may have an influence on it, like metabolic profile and transformations, impurities and plasma biding proteins, must be considered. In this field, recent hyphenated analytical methods, such as LC-MS/MS, GC-MS/MS or more complex couplings, can provide more complete information. The aim of this review is to report the processes required for the validation of drug efficacy with reference to the description of 'classic' and modern techniques used.