Stress testing of linaclotide: Development of a validated stability-indicating RP-HPLC method

Linaclotide, a first-in-class guanylate cyclase-C agonist, was recently approved by US Food and Drug Administration (FDA) as a promising pharmacotherapy for the management of constipation-predominant irritable bowel syndrome (IBS). In this communication, we present a novel stability-indicating reverse-phase high-performance liquid chromatography (RP-HPLC) method for the quantitative determination of linaclotide along with its degradation products. During the International Conference on Harmonization (ICH) prescribed stress study, linaclotide was found susceptible to degrade under hydrolytic (acid and base) and oxidative (peroxide) conditions. The separation of the degradants from the analyte was achieved on a Zorbax Eclipse XDB C 8 Column (250 mm × 4.6 mm, 5 μm) using 0.01 N potassium dihydrogen orthophosphate buffer and acetonitrile (80:20 v / v ) as mobile phase at a flow rate of 1.00 mL min −1 at column temperature of 40 °C. The detection of the column effluents was realized on a photodiode array detector set at 220 nm. Under the above optimal condition, the method was validated with respect to specificity, linearity, range, precision, robustness, and sensitivity in compliance to the regulatory requirements.