Enantioselective polar-organic mode high-performance liquid chromatographic separation of lifitegrast on immobilized polysaccharide stationary phase and its application to pH-dependent chiral interconversion studies.

(S)-Lifitegrast (LFT) is the novel integrin antagonist, approved by the Food and drug administration, to treat signs and symptoms of dry eye disease. Synthesis of racemic LFT, preparative and analytical enantiomer separation, and chiral interconversion studies are lacking in the literature. Hence, in our study, synthesis of LFT racemate, chiral preparative purification procedure of enantiomer, and comprehensive analytical advancements are focused on rapid enantioselective separation and pH-dependent chiral interconversion studies. The synthesis of LFT racemate employed 2-amino-3-(3-(methylsulfonyl)phenyl)propanoic acid hydrochloride and 2-(benzofuran-6-carbonyl)-5,7-dichloro-1,2,3,4-tetrahydroisoquinoline-6-carbonyl chloride as starting materials. (R)-LFT was isolated from the racemate by preparative chiral HPLC and characterized using Q-TOF, FT-IR, NMR spectroscopy, and chiral HPLC. The purity of (R)-LFT was determined to have an enantiomeric excess of 99.12%. A precise, accurate, rapid HPLC-DAD enantioselective analytical method has been developed on Chiralpak IC [tris(3,5-dichloro phenyl carbamate) immobilized on cellulose] using water and methanol as mobile phase. The chiral interconversion study reveals 0.22% and 0.21% of interconversion of (S)-LFT into (R)-LFT at 80°C in pH 7.4 and 9.5 buffers, respectively, on the 24th day. An alternative route to enantioselective synthesis of LFT enantiomers by chromatographic separation is proposed. The validated enantioselective HPLC method will help to test the regular quality control samples.

Advances and challenges in the pharmacokinetics and bioanalysis of chiral drugs.

Enantioselective analytical approaches are essential for monitoring pharmacokinetics and acquiring accurate data to better understand the role of stereochemistry in pharmacokinetics. Enantioselectivity significantly impacts the pharmacokinetics of chiral drugs, especially in metabolic profile, leading to toxicity of enantiomer. Consequently, there is a need to study the pharmacokinetics of enantiomerically pure drugs and racemates as they differ in affinity with enzymes and proteins. Combining the best enantioseparation conditions with the specified biological matrix and the intended purpose of the analysis is a challenging task. This review discusses the importance of chirality in stereoselective pharmacokinetics with more relevant examples, various enantioselective analytical techniques, and stationary phases employed. Challenges such as lack of universal chiral columns, biological inversion of the isomers, and others have been discussed. Further presented the recent advances in the screening of chiral drugs and innovative improvements in the analytical approaches for chiral molecule analysis such as supercritical fluid chromatography, simulated moving bed chromatography, and other techniques are discussed.