pf-610355 pf-610355 pf-610355 (also known as pf-00610355 or pf-610,355) is an inhalable ultra-long-acting β2 adrenoreceptor agonist (ultra-laba) that was investigated as a treatment of asthma and copd by pfizer. it utilizes a sulfonamide agonist headgroup, that confers high levels of intrinsic crystallinity that could relate to the acidic sulfonamide motif supporting a zwitterionic form in the solid state. optimization of pharmacokinetic properties minimized systemic exposure following inhalation and reduced systemically-mediated adverse events. its in vivo duration on action confirmed its potential for once-daily use in humans. pf-610355clinical dataroutes ofadministrationinhalationatc codenonelegal statuslegal status development terminated identifiers iupac name n--2-phenyl}ethyl]amino}-2-methylpropyl)phenyl]acetamide cas number862541-45-5pubchem cid11505444chemspider9680243 yuniizh5smu97ajchemblchembl1240967 ychemical and physical dataformulac34h39n3o6smolar mass617.76 g·mol−1 the investigation and development of pf-610355 were discontinued in 2011, likely for strategic and regulatory reasons.