Analysis of in-process control and cleaning samples plays a critical role in pharmaceutical development to control the quality of active pharmaceutical ingredient (API). Currently, conventional HPLC equipped with 4.6mm id columns are widely used for such applications and suffer high consumption of organic solvents in mobile phase. Capillary HPLC is an alternative analytical technology and consumes only about 1% of mobile phase used by conventional HPLC. However, capillary HPLC is known to have the drawback of low sensitivity and accuracy, limiting its application.

Recently, a new model of capillary HPLC has been developed with improved sensitivity and accuracy. Its performance has been close to that of conventional HPLC. Improved capillary HPLC has been successfully applied to the analysis of in-process control and cleaning samples in pharmaceutical development. It is very promising in terms of green chromatography for pharmaceutical industry.