A convergent synthesis of the immunosuppressant FTY720 employing aqueous Wittig chemistry

Synthesis, characterization and control of eight process related and two genotoxic fingolimod impurities by a validated RP-UPLC method

An HPLC method has been described in European and United States Pharmacopoeias (Ph. Eur. and USP) for determination of nine organic impurities (imp A-I) in fingolimod hydrochloride, a synthetic sphingosine-1-phosphate receptor modulator. The manufacturing process of fingolimod hydrochloride consists of multi-step chemical synthesis wherein controls of precursors, intermediates and process steps should be done to assure the final quality of drug substance. We synthesized and isolated eight process related impurities (FINI imp A-H) of fingolimod, different than the pharmacopoeial impurities. One unknown process-related impurity was found in key-intermediate (FINI) and was identified by LC-MS. Characterization of all impurities were done by using spectroscopic techniques (¹ H & ¹³ C NMR, FTIR, MS), and the mechanistic pathways to the formation of these impurities were also discussed. Two of these impurities were evaluated as potential genotoxic impurities due to their alerting structures and alkylating properties (alkyl sulfonates and alkyl halides, class 3, ICH M7). We also developed and validated a RP-UPLC method in line with ICH Q2 guidelines for control these impurities (FINI imp A-H) and to assure the pharmacopoeial quality drug substance.

Synthesis and evaluation of fluorinated fingolimod (FTY720) analogues for sphingosine-1-phosphate receptor molecular imaging by positron emission tomography

Sphingosine-1-phosphate (S1P) is a lysophospholipid that evokes a variety of biological responses via stimulation of a set of cognate G-protein coupled receptors (GPCRs): S1P1-S1P5. S1P and its receptors (S1PRs) play important roles in the immune, cardiovascular, and central nervous systems and have also been implicated in carcinogenesis. Recently, the S1P analogue Fingolimod (FTY720) has been approved for the treatment of patients with relapsing multiple sclerosis. This work presents the synthesis of various fluorinated structural analogues of FTY720, their in vitro and in vivo biological testing, and their development and application as [(18)F]radiotracers for the study of S1PR biodistribution and imaging in mice using small-animal positron emission tomography (PET).